New York Metropolitan Flora

Genus: Populus

By Steven D. Glenn

Not peer reviewed

Last Modified 03/11/2013

Back to Salicaceae

Nomenclature

Populus L., Sp. Pl. 2: 1034. 1753. Gen. Pl., ed. 5, 456. 1754. LECTOTYPE: Populus alba L. designated by Britton & Brown (1913).

Tremula Dumort., Bijdr. Natuurk. Wetensch. 1: 46. 1826. TYPE: Tremula vulgaris Opiz (=Populus tremula L.).

Octima Raf., Alsogr. Amer. 42. 1838. TYPE: Octima canescens Raf. (Populus canescens (Aiton) Sm.).

Monilistus Raf., Alsogr. Amer. 42. 1838. TYPE: Monilistus monilifera Raf.

Aigeiros Tidestr., Elys. Marian., Ferns 2: 15. 1910. TYPE: Unknown.

Key to the species of Populus

1. Leaves white-tomentose beneath...2
1. Leaves glabrous or nearly so (densely white-tomentose on young leaves of P. balsamifera and P. grandidentata)...3

2. Leaves lobed; lower surface densely tomentose...Populus alba
2. Leaves entire or dentate; lower surface more sparsely tomentose...Populus ×canescens

3. Petioles terete...4
3. Petioles strongly laterally compressed...5

4. Leaf outline slightly convex toward the blunt or rounded tip; pedicels 2-8 mm long...Populus heterophylla
4. Leaf outline slightly concave toward the very acute to short acuminate tip; pedicels less than 2 mm long...Populus balsamifera

5. Leaves strongly deltoid or diamond-shaped; leaf margin with firm, colorless border thicker than the adjacent major veinlets; stamens more than 14; scales of aments glabrous, fringed with many thread-like segments...6
5. Leaves orbicular to reniform or obscurely deltoid; leaf margins often without colorless border; stamens less than 13; scales of aments pilose, fringes with only 3-7 linear or narrowly lanceolate segments...8

6. Glands prominent at junction of blade and petiole; leaf blade deltoid...7
6. Glands absent at junction of blade and petiole; leaf blade diamond-shaped...Populus nigra

7. Blades of early leaves light green above; leaf margins very coarsely dentate, the largest teeth 2-6 mm deep, ciliate...Populus deltoides
7. Blades of early leaves dark green above; leaf margins coarsely dentate, the largest teeth 1-2 mm deep, not ciliate...Populus ×jackii

8. Leaf margins closely crenate-serrate; buds and new growth glabrous...Populus tremuloides
8. Leaf margins closely undulate dentate; buds and new growth tomentose...Populus grandidentata

List of Populus Species

References to Populus

  • Anonymous 1996. Historic tree merits extraordinary measures. Arbor Age 16: 32-3.
  • Archibold, O. W.; Wilson, M. R. 1978. Spatial pattern and population dynamics of Populus tremuloides in a Saskatchewan aspen grove. Canad. Field-Naturalist 92: 369-74.
  • Ballach, H. J. 1997. Suitability and use of poplars as bioindicators: A new concept. Environ. Sci. Pollution Res. Int. 4: 37-45.
  • Barnes, B. V. 1978. Pollen abortion in Betula and Populus (section Leuce). Michigan Bot. 17(4): 167-72.
  • Barnes, B. V. 1969. Natural variation and delineation of clones of Populus tremuloides and P. grandidentata in northern lower Michigan. Silvae Genet. 18: 130-42.
  • Barnes, B. V. 1966. The clonal growth habit of American aspens. Ecology 47: 439-47.
  • Barnes, B. V. 1959. Natural variation and clonal development of Populus tremuloides and P. grandidentata in northern lower Michigan. Ph.D. Dissertation Univ. Michigan, Ann Arbor334 p.
  • Barnes, B. V. 1961. Hybrid aspens in the Lower Peninsula of Michigan. Rhodora 63: 311-24.
  • Barnes, B. V.; Pregitzer, K. S. 1985. Occurrence of hybrids between bigtooth and trembling aspen in Michigan. Canad. J. Bot. 63: 1888-90.
  • Barrett, J. W. et.al. 1993. Mitochondrial DNA variation and genetic relationships of Populus species. Genome 36: 87-93.
  • Bate, G. C.; Canvin, D. T. 1971. The effect of some environmental factors on the growth of young aspen trees (Populus tremuloides) in controlled environments. Canad. J. Bot. 49: 1443-53.
  • Berrang, P.; Karnosky, D. F.; Bennett, J. P. 1991. Natural selection for ozone tolerance in Populus tremuloides: an evaluation of nationwide trends. Canad. J. Forest Res. 21: 1091-7.
  • Berry, E. W. 1917. Notes on the history of the willows and poplars. Pl. World 20: 16-28.
  • Bertenshaw, J. L. 1965. The clonal structure of selected aspen stands in northern Lower Michigan. M.S. Thesis Univ. Michigan, Ann Arbor, Mich.,
  • Bessey, C. E. 1904. The number and weight of cottonwood seeds. Science 20: 118-119.
  • Bialobok, S. (eds.) (1973): 1973. The poplars (Populus L.). U.S. National Technical Information Service, Springfield, VA. (Translated from Polish, 1976.)
  • Blackburn, K. B.; Heslop-Harrison, J. W. 1924. A preliminary account of the chromosomes and chromosome behavior in the Salicaceae. Ann. Bot. (London) 38: 361-378.
  • Boom, B. K. 1957. Populus canadensis Moench versus Populus euramericana Guinier. Acta Bot. Neerl. 6: 54-59.
  • Bradshaw, H. D.; Stettler, R. F. 1995. Molecular genetics of growth and development in Populus. 4. Mapping QTLs with large effects on growth, form, and phenology in a forest tree. Genetics 139: 963-73.
  • Britton, Nathaniel L. 1886. Leaf-forms of Populus grandidentata. Bull. Torrey Bot. Club 13: 89-91.
  • Britton, Nathaniel L. 1887. Note on the flowers of Populus heterophylla L. Bull. Torrey Bot. Club 14: 114-5.
  • Brown, J. K.; Debyle, N. V. 1987. Fire damage, mortality, and suckering in aspen. Canad. J. Forest Res. 17(9): 1100-9.
  • Buckman, R. E.; Blankenship, L. H. 1965. Repeated spring prescribed burning reduces abundance and vigor of aspen root suckering. J. Forest. 63(1): 23-5.
  • Carey, J. H. 1994. Populus grandidentata. Fire Effects Information System, [Online]. ()
  • Charrette, P. 1990. The effect of photoperiod on apical growth cessation in tamarack (Larix laricina) and balsam poplar (Populus balsamifera) provenances from northern Ontario. M.S. Thesis Lakehead Univ., Thunder Bay, Ontario80 p.
  • Cheliak, W. M.; Dancik, B. P. 1982. Genetic diversity of natural populations of a clone-forming tree Populus tremuloides. Canad. J. Genet. Cytol. 24(5): 611-6.
  • Chester, E. W.; Wofford, B. E.; McKinney, L. E.; Campbell, D. 1996. Rare and noteworthy vascular plants from the Fort Campbell Military Reservation, Kentucky and Tennessee. Sida 17: 269-274.
  • Churchill, G. B.; John, H. H.; Duncan, D. P.; Hodson, A. C. 1964. Long-term effects of defoliation of aspen by the forest tent caterpillar. Ecology 45: 630-3.
  • Clark, C. S.; Weber, J. A.; Lee, E. H.; Hogsett, W. E. 1996. Reductions in gas exchange of Populus tremuloides caused by leaf aging and ozone exposure. Canad. J. Forest Res. 26: 1384-91. (French summary)
  • Clarke, B. B.; Brennan, E. 1980. Evidence for cadmium and ozone interaction on Populus tremuloides. J. Arboric. 6(5): 130-4.
  • Clausen, T. P. et.al. 1989. Chemical model for short-term induction in quaking aspen (Populus tremuloides) foliage against herbivores. J. Chem. Ecol. 15: 2335-46.
  • Collingwood, G. H. 1941. Aspen. Amer. Forests 47: 528-9.
  • Collinson, M. E. 1992. The early fossil history of the Salicaceae. Proc. Roy. Soc. London Ser. B Biol. Sci. 98: 155-167.
  • Comtois, P.; Simon, J. P.; Payette, S. 1986. Clonal constitution and sex ratio in northern populations of balsam poplar Populus balsamifera. Holarctic Ecology 9: 251-260.
  • Connolly, B. A. 2008. Six new vascular plant taxa for Connecticut. Rhodora 110: 354-358.
  • Connolly, V.; Eckenwalder, J. E. 1983. Hybridization between white poplar and native aspens in southern Ontario. Amer. J. Bot. 70(5)(suppl.): 110. (Abstract)
  • Cottam, W. P. 1966. Quaking aspen.
  • Covington, W. W. 1975. Altitudinal variation of chlorophyll concentration and reflectance of the bark of Populus tremuloides. Ecology 56: 715-20.
  • Cripps, C. L. 1992. Aspen mycorrhizae: ecology, synthesis, and growth studies. M.S. Thesis Virginia Polytechnic Institute, Blacksburg, VA,
  • Critchfield, W. B. 1960. Leaf dimorphism in Populus trichocarpa. Amer. J. Bot. 47: 699-711.
  • Curtis, J. D.; Lersten, N. R. 1974. Morphology, seasonal variation and function of resin glands on buds and leaves of Populus deltoides. Amer. J. Bot. 61: 835-845.
  • Curtis, J. D.; Lersten, N. R. 1978. Heterophylly in Populus grandidentata (Salicaceae) with emphasis on resin glands and extrafloral nectaries. Amer. J. Bot. 65(9): 1003-10.
  • D'Ovidio, R.; Mugnozza, G. S.; Tanzarella, O. A. 1991. RDNA cloning and rapid hybrid identification in populus spp. (Salicaceae). Pl. Syst. Evol. 177: 165-74.
  • Daigle, B. I.; Simpson, J. D. 2009. Collecting and processing Salicaceae seeds. Native Plants J. 10: 48-51.
  • Davis, J. D.; Evert, R. F. 1968. Seasonal development of the secondary phloem in Populus tremuloides. Bot. Gaz. 129(1): 1-8.
  • Day, M. W.; Vogel, F. H. 1944. Silviculture and utilization of balsam poplar. J. Forest. 42(7): 512-4.
  • Day, R. A. et.al. 2003. Propagation protocol for bareroot bigtooth and quaking aspen using seeds. Native Plants J. 4: 125-128.
  • Dayanandan, S. et.al. 1998. Isolation and characterization of microsatellites in trembling aspen (Populus tremuloides). Theor. Appl. Genet. 96: 950-956.
  • Dean, M. A.; Letner, C. A.; Eley, J. H. 1993. Effect of autumn foliar senescence on chlorophyll a:b ratio and respiratory enzymes of Populus tremuloides. Bull. Torrey Bot. Club 120: 269-74.
  • Debyle, N. V. 1964. Detection of intraclonal aspen root connections by tracers and excavation. Forest Sci. 8: 403-10.
  • DenHeyer, J.; Seymoir, N. 1978. Aspen and balsam poplar seed collection and storage. Tree Pl. Notes 29: 35.
  • Denneler, B; Bergeron, Y.; Begin, Y. 1999. An attempt to explain the distribution of the tree species composing the riparian forests of Lake Duparquet, southern boreal region of Quebec, Canada. Canad. J. Bot. 77: 1744-1755.
  • Dewit, L.; Reid, D. M. 1992. Branch abscission in balsam poplar (Populus bassamifera): characterization of the phenomenon and the influence of wind. Int. J. Plant Sci. 153(4): 556-64.
  • Dickmann, D. I. 1971. Photosynthesis and respiration by developing leaves of cottonwood (Populus deltoides Bartr.). Bot. Gaz. 132: 253-259.
  • Donnelly, J. R. 1974. Seasonal changes on photosynthate transport within elongating shoots of Populus grandidentata. Canad. J. Bot. 52(12): 2547-59.
  • Drew, A. P.; Bazzaz, F. A. 1979. Response of stomatal resistance and photosynthesis to night temperature in Populus deltoides. Oecologia 41: 89-98.
  • Drew, A. P.; Bazzaz, F. A. 1978. Variation in distribution of assimilate among plant parts in three populations of Populus deltoides. Silvae Genet. 27: 189-93.
  • Dudek, D. M. et.al. 1998. Tree growth responses of Populus deltoides and Juglans nigra to streamflow and climate in a bottomland hardwood forest in central Ohio. Amer. Midl. Naturalist 140: 233-244.
  • Eckenwalder, J. E. 1977. North American cottonwoods (Populus, Salicaceae) of sections Abaso and Aigeiros. J. Arnold Arbor. 58: 193-208.
  • Eckenwalder, J. E. 1984. Natural intersectional hybridization between North American species of Populus (Salicaceae) in sections Aigeiros and Tacamahaca. II. Taxonomy. Canad. J. Bot. 62: 325-35.
  • Einspahr, D. W.; Benson, M. K. 1967. Geographic variation of quaking aspen in Wisconsin and upper Michigan. Silvae Genet. 16: 106-112.
  • Einspahr, D. W.; Winton, L. L. 1977. The genetics of quaking aspen.
  • Engstrom, A. 1948. Growing cottonwood from seed. J. Forest. 46: 130-2.
  • Erlanson, E. W.; Hermann, F. J. 1927. The morphology and cytology of perfect flowers in Populus tremuloides Michx. Pap. Michigan Acad. Sci. 8: 97-113.
  • Falinski, J. B. 1980. Changes in the sex- and age-ration in populations of pioneer dioecious woody species (Juniperus, Populus, Salix) in connection with the course of vegetation succession in abandoned farmlands. Ekologia Polska 28: 327-65.
  • Farmer, M. M. 1977. Variation and identification of hybrid and backcross populations of Populus grandidentata and P. tremuloides. M.S. Thesis Univ. Michigan, Ann Arbor, MI,
  • Farmer, R. E. 1993. Latitudinal variation in height and phenology of balsam poplar. Silvae Genet. 42: 148-53.
  • Farmer, R. E. 1966. Variation in time of flowering and seed dispersal of eastern cottonwood in the lower Mississippi Valley. Forest Sci. 12: 343-7.
  • Farmer, R. E. 1964. Sex ratio and sex-related characters in eastern cottonwood. Silvae Genet. 13: 116-8.
  • Farmer, R. E. 1970. Variation and inheritance of eastern cottonwood growth and wood properties under two soil moisture regimes. Silvae Genet. 19: 5-8.
  • Farmer, R. E.; Bonner, F. T. 1967. Germination and initial growth of eastern cottonwood as influenced by moisture stress, temperature, and storage. Bot. Gaz. 128(3-4): 211-5.
  • Farmer, R. E.; Reinholt, R. W. 1985. Genetic variation in dormancy relations of balsam poplar along a latitudinal transect in northwestern Ontario. Silvae Genet. 35: 38-42.
  • Farwell, O. A. 1919. Necessary changes in botanical nomenclature. Rhodora 21: 101-103.
  • Faust, M. E. 1936. Germination of Populus grandidentata and P. tremuloides, with particular reference to oxygen consumption. Bot. Gaz. 97: 808-21.
  • Fechner, G. H. 1972. Development of the pistillate flower of Populus tremuloides following controlled pollination. Canad. J. Bot. 50(12): 2503-9.
  • Fechner, G. H.; Burr, K. E.; Myers, J. F. 1981. Effects of storage, temperature, and moisture stress on seed germination and early seedling development of trembling aspen. Canad. J. Forest Res. 11: 718-722.
  • Fisher, M. J. 1928. The morphology and anatomy of the flowers of the Salicaceae II. Amer. J. Bot. 15: 372-394.
  • Fisher, M. J. 1923. The anatomy of the flower of the Salicaceae. Ph.D. Dissertation Cornell Univ., Ithaca, NY165 p.
  • Fisher, M. J. 1928. The morphology and anatomy of the flowers of the Salicaceae I. Amer. J. Bot. 15: 307-326.
  • Flora of North America Editorial Committee. 2010. Flora of North America. Volume 7. Magnoliophyta: Salicaceae to Brassicaceae. Oxford Univ. Press, New York. , 797 pages. (ISBN 9780195318227)
  • Fordyce, J. A.; Ehrle, E. B.; Thompson, P. W. 1996. The big trees of Michigan: 15. Populus deltoides Marsh. Michigan Bot. 35: 54-6.
  • Foster, B. L.; Gross, K. L. 1999. Temporal and spatial patterns of woody plant establishment in Michigan old fields. Amer. Midl. Naturalist 142: 229-243.
  • Foster, G. S. 1986. Provenance variation of eastern cottonwood in the lower Mississippi Valley. Silvae Genet. 35: 32-8.
  • Frey, B. R. et.al. 2003. An analysis of sucker regeneration of trembling aspen. Canad. J. Forest Res. 33: 1169-1179.
  • Friend, M. M. 1981. Genetic variation in juvenile traits of eastern cottonwood from the southern United States. M.S. Thesis Mississippi State Univ.117 p.
  • Fuller, G. D. 1912. Germination and growth of the cottonwood upon the sand dunes of Lake Michigan near Chicago. Trans. Illinois State Acad. Sci. 5: 137-143.
  • Gagnon, Z. E.; Karnosky, D. F.; Dickson, R. E.; Isebrands, J. G. 1992. Effect of ozone on chlorophyll content in Populus tremuloides. Amer. J. Bot. 79: 107.
  • Gambill, W. G. 1977. America's vagabond tree. Amer. Horticulturist 56(5): 18-20,44.
  • Gates, F. C. 1930. Aspen associations in northern lower Michigan. Bot. Gaz. 90: 233-59.
  • Gebre, G. M.; Kuhns, M. R. 1991. Seasonal and clonal variations in drought tolerance of Populus deltoides. Canad. J. Forest Res. 21: 910-6.
  • Gendel's, T. V.; Budantsev, L. Y. 1991. The study of variability of blade form in Populus deltoides (Salicaceae) using a numerical index. Bot. Zhurn. (Moscow & Lenengrad) 76(5): 747-52. (In Russian)
  • Gerard, W. R. 1880. Note on Populus balsamifera L., var. candicans Gray. Bull. Torrey Bot. Club 7: 57.
  • Goffinet, M. C.; Larson, P. R. 1981. Structural changes in Populus deltoides terminal buds and in the vascular transition zone of the stems during dormancy induction. Amer. J. Bot. 68(1): 118-29.
  • Gol'-Traf, E. I. 1982. Study of wood of some representatives of the genus Populus Salicaceae using scanning electron microscopy. Bot. Zhurn. St. Petersburg 67: 1070-1073. (In Russian)
  • Graf, J. 1921. Beitrage zur Kenntnis der Gattung Populus. Ber. Deutsch. Bot. Ges. 39: 193-194.
  • Graham, S. A.; Harrison, R. P.; Westell, C. E. 1963. Aspens. Univ. Michigan Press, Ann Arbor.
  • Grant, M. C.; Mitton, J. B. 1979. Elevational gradients in adult sex ratios and sexual differentiation in vegetative growth rates of Populus tremuloides Michx. Evolution 33: 914-8.
  • Greene, D. F. et.al. 1999. A review of the regeneration dynamics of North American boreal forest tree species. Canad. J. Forest Res. 29: 824-839.
  • Guilloy, F. H. et.al. 2002. Dispersal, germination, and survival of Populus nigra L. (Salicaceae) in changing hydrologic conditions. Wetlands 22: 478-488.
  • Hacke, U.; Sauter, J. J. 1996. Drought-induced xylem dysfunction in petioles, branches, and roots of Populus balsamifera L. and Alnus glutinosa (L.) Gaertn. Pl. Physiol. (Rockville) 111: 413-417.
  • Hackskaylo, E.; Vozzo, J. A. 1971. Mycorrhizae of Populus in the United States.
  • Hamzeh, M. et.al. 2007. Asymmetrical natural hybridization between Populus deltoides and P. balsamifera (Salicaceae). Canad. J. Bot. 85: 1227-1232.
  • Hamzeh, M.; Dayanandan, S. 2004. Phylogeny of Populus (Salicaceae) based on nucleotide sequences of chloroplast TRNT-TRNF region and nuclear RDNA. Amer. J. Bot. 91: 1398-1408.
  • Hamzeh, M.; Perinet, P.; Dayanandan, S. 2006. Genetic relationships among species of Populus (Salicaceae) based on nuclear genomic data. J. Torrey Bot. Soc. 133: 519-527.
  • Hardin, E. D. 1984. Variation in seed weight, number per capsule, and germination in Populus deltoides Bartr. trees in southeastern Ohio. Amer. Midl. Naturalist 112: 29-34. (See also Hardin, E.D. Ph.D. Ohio Univ., Athens, OH. 1982.)
  • Hardin, E. D. 1983. Patterns in floodplain herbaceous vegetation and some aspects of the population biology of Populus deltoides on the Hocking River, Ohio. Ph.D. Dissertation Ohio State Univ., Columbus, OH279 p.
  • Harris, H. T. 1990. Populus balsamea. ()
  • Hastings, G. T. 1918. Some abnormal poplar flowers. Torreya 18: 16-20.
  • Heizmann, D.; Shull, C. A. 1944. The inflorescences of the cotton-wood poplar. Chicago Naturalist 7: 26-29.
  • Henry, R. M.; Barnes, B. V. 1977. Comparative reproductive ability of bigtooth and trembling aspen and their hybrid. Canad. J. Bot. 55: 3093-8.
  • Hitch, A. D. 1913. The Balm of Gilead tree (located at Balmville, Orange County). Tree Talk 1: 8.
  • Holden, R. 1912. Reduction and reversion in the North American Salicales. Ann. Bot. 26: 165-173.
  • Holifield, J. L. 1989. Populus deltoides. ()
  • Hood, J. D. 1967. Patterns of vegetation and distribution of Populus deltoides Marsh., within the Hocking River flood plain. M.S. Thesis Ohio Univ., Athens, OH143 p.
  • Hosner, J. F. 1959. Survival, root, and shoot growth of six bottomland tree species following flooding. J. Forest. 57: 927-8.
  • Hosner, J. F. 1958. The effects of complete inundation upon seedlings of six bottomland tree species. Ecology 39: 371-3.
  • Houtzagers, G. 1951. The poplars deltoides, tremuloides, and grandidentata in their natural habitat.
  • Howard, J. L. 1996. Populus tremuloides. Fire Effects Information System, [Online].
  • Hu, C. C.; Crovello, T. J.; Sokal, R. R. 1985. The numerical taxonomy of some species of Populus based only on vegetative characters. Taxon 34(2): 197-206.
  • Hyun, J. O.; Rajora, O. P.; Zsuffa, L. 1987. Genetic variation in trembling aspen in Ontario based on isozyme studies. Canad. J. Forest Res. 17: 1134-8.
  • Hyun, J. O.; Rajora, O. P.; Zsuffa, L. 1987. Inheritance and linkage of isozymes in Populus tremuloides. Genome 29: 384-8.
  • Isebrands, J. G.; Larson, P. R. 1977. Vascular anatomy of the nodal region in Populus deltoides Bartr. Amer. J. Bot. 64: 1066-77.
  • Isebrands, J. G.; Larson, P. R. 1977. Organisation and ontogeny of the vascular system in the petiole of eastern cottonwood. Amer. J. Bot. 64(1): 65-77.
  • Ivkovich, M. 1996. Genetic variation of wood properties in balsam poplar (Populus balsamifera L.). Silvae Genet. 45: 119-124.
  • James, T. D. W.; Smith, D. W. 1978. Seasonal changes in the caloric value of the leaves and twigs of Populus tremuloides. Canad. J. Bot. 56(15): 1804-5.
  • James, T. D. W.; Smith, D. W. 1978. Seasonal changes in the major ash constituents of leaves and some woody components of trembling aspen and red osier dogwood. Canad. J. Bot. 56(15): 1798-803.
  • Jelinkova, H. et.al. 2009. Molecular and dendrochronological analysis of natural root grafting in Populus tremuloides (Salicaceae). Amer. J. Bot. 96: 1500-1505.
  • Jelinski, D. W.; Cheliak, W. M. 1992. Genetic diversity and spatial subdivision of Populus tremuloides (Salicaceae) in a heterogeneous landscape. Amer. J. Bot. 79: 728-36.
  • Jobidon, R.; Thibault, J. R. 1981. Allelopathic effects of balsam poplar on green alder germination. Bull. Torrey Bot. Club 108: 413-8.
  • Jogia, M. K. et.al. 1989. An antifeedant in balsam poplar inhibits browsing by snowshoe hares. Oecologia 79: 189-192.
  • Johnson, L. P. V. 1946. Effect of humidity on the longevity of Populus and Ulmus seeds in storage. Canad. J. Res., Sect. C, Bot. Sci. 24: 298-302.
  • Jokela, J. J.; Mohn, C. A. 1976. Geographic variation in eastern cottonwood. In: Proceedings of the symposium on eastern cottonwood and related species, 28 Sept.-2 Oct. 1976, Greenv. Louisiana State Univ., Baton Rouge, LA. , 109-25 pages.
  • Julkunen-Tiitto, R. 1986. A chemotaxonomic survey of phenolics in leaves of northern Salicaceae species. Phytochemistry 25: 663-668.
  • Jurik, T. W. 1986. Temporal and spatial patterns of specific leaf weight in successional northern hardwood tree species. Amer. J. Bot. 73(8): 1083-92.
  • Jurik, T. W.; Weber, J. A.; Gates, D. M. 1984. Short-term effects of CO2 on gas exchange of leaves of bigtooth aspen (Populus grandidentata) in the field. Pl. Physiol. (Lancaster) 75: 1022-6.
  • Kaeiser, M. 1955. Fiber size in Populus deltoides Marsh. in relation to lean of trunk and position in trunk. Bull. Torrey Bot. Club 82: 57-61.
  • Karels, T. J.; Boonstra, R. 2003. Reducing solar heat gain during winter: The role of white bark in northern deciduous trees. Arctic 56: 164-178.
  • Karnosky, D. F. 1976. Threshold levels for foliar injury to Populus tremuloides by sulfur dioxide and ozone. Canad. J. Forest Res. 6: 166-9.
  • Karnosky, D. F.; Gagnon, Z. E.; Reed, D. D.; Witter, J. A. 1992. Growth and biomass allocation of sympatric and asympatric Populus tremuloides clones in response to seasonal ozone exposures. Canad. J. Forest Res. 22: 1785-8.
  • Karrenberg, S.; Suter, M. 2003. Phenotypic trade-offs in the sexual reproduction of Salicaceae from flood plains. Amer. J. Bot. 90: 749-754. (5)
  • Kaufert, F. 1937. Factors influencing the formation of periderm in aspen. Amer. J. Bot. 24: 24-30.
  • Kaul, R. B. 1995. Reproductive structure and organogenesis in a cottonwood, Populus deltoides (Salicaceae). Int. J. Plant Sci. 156(2): 172-80.
  • Kelliher, F. M.; Tauer, C. G. 1980. Stomatal resistance and growth of drought-stressed eastern cottonwood from a wet and dry site. Silvae Genet. 29: 166-71.
  • Kennedy, H. E. 1985. Cottonwood (Populus deltoides Bartr. ex Marsh. and P. trichocarpa Torr. & Gray).
  • Klopfenstein, N. B. et.al. 1997. Micropropagation, genetic engineering, and molecular biology of Populus.
  • Kneeshaw, D. D.; Bergeron, Y. 1996. Ecological factors affecting the abundance of advanced regeneration in Quebec's southwestern boreal forest. Canad. J. Forest Res. 26: 888-98. (French summary)
  • Kubiske, M. E. et al. et.al. 1997. Populus tremuloides photosythesis and crown architecture in response to elevated CO2 and soil N availability. Oecologia 110: 328-36.
  • Kull, O. et al. et.al. 1996. Photosynthetic responses of aspen clones to simultaneous exposures of ozone and CO2. Canad. J. Forest Res. 26: 639-48. (French summary)
  • Lamont, E. 1992. Swamp cottonwood grove threatened. Long Island Botanical Society Newsletter 2: 4.
  • Larson, P. R.; Fisher, D. G. 1983. Xylary union between elongating lateral branches and the main stem in Populus deltoides. Canad. J. Bot. 61: 1040-51.
  • Larson, P. R.; Gordon, J. C. 1969. Leaf development, photosynthesis, and C14 distribution in Populus deltoides seedlings. Amer. J. Bot. 56: 1058-66.
  • Larson, P. R.; Isebrands, J. G. 1978. Functional significance of the nodal constricted zone in Populus deltoides. Canad. J. Bot. 56(7): 801-4.
  • Lavertu, D.; Mauffette, Y.; Bergeron, Y. 1994. Effects of stand age and litter removal on the regeneration of Populus tremuloides. J. Veg. Sci. 5: 561-8.
  • Lawrey, J. D. 1977. Trace metal accumulation by plant species from a coal strip-mining area in Ohio. Bull. Torrey Bot. Club 104: 368-375.
  • Legionnet, A. et.al. 1997. Sexual and asexual reproduction in natural stands of Populus nigra. Botanica Acta 110: 257-263.
  • Leskinen, E.; Alstrom-Rapaport, C. 1999. Molecular phylogeny of Salicaceae and closely related Flacourtiaceae: evidence from 5.8S, ITS 1 and ITS 2 of the rDNA. Pl. Syst. Evol. 215: 209-227.
  • Lester, D. T. 1963. Variation in sex expression in Populus tremuloides Michx. Silvae Genet. 12: 141-80.
  • Lester, D. T. 1963. Floral initiation and development in quaking aspen. Forest Sci. 9: 323-9.
  • Li, K.; Huang, M.; Wang, M.; Chen, D.; He, Z. 1996. Study on DNA polymorphisms and phylogenetics of Populus: Aigeiros, Tacamahaca, and Leuce section. J. Nanjing Forest. Univ. 20(1): 6-11. (In Chinese, English summary)
  • Li, W. D. et.al. 1995. The secretory stigmas in Populus: Development, cytochemistry, ultrastructure and their relation to intersectional incompatibility. Acta Bot. Sin. 37: 514-521.
  • Lindroth, R. L.; Hwang, S. Y. 1996. Clonal variation in foliar chemistry of quaking aspen (Populus tremuloides Michx.). Biochem. Syst. Ecol. 24: 357-64.
  • Lindroth, R. L.; Kinney, K. K.; Platz, C. L. 1993. Responses of deciduous trees to elevated atmospheric CO2: productivity, phytochemistry, and insect performance. Ecology 74: 763-77.
  • Liu, Z.; Furnier, G. R. 1993. Comparison of allozyme, RFLP, and RAPD markers for revealing genetic variation within and between trembling aspen and bigtooth aspen. Theor. Appl. Genet. 87: 97-105.
  • Loach, K. 1970. Shade tolerance in tree seedlings. II. Growth analysis of plants raised under artificial shade. New Phyt. 69: 273-86.
  • Loach, K. 1967. Shade tolerance in tree seedlings. I. Leaf photosynthesis and respiration in plants raised under artificial shade. New Phyt. 66: 607-21.
  • Lund, S. T.; Furnier, G. R.; Mohn, C. A. 1992. Isozyme variation in quaking aspen in Minnesota. Canad. J. Forest Res. 22: 521-4.
  • Maini, J. S.; Coupland, R. T. 1964. Anomalous floral organization in Populus tremuloides. Canad. J. Bot. 42: 835-9.
  • Mansfield, J. L. et.al. 1999. Genotypic variation for condensed tannin production in trembling aspen (Populus tremuloides, Salicaceae) under elevated CO2 and in high- and low-fertility soil. Amer. J. Bot. 86: 1154-1159.
  • Marcet, E. 1961. Uber die geographische variabilitat blatt-morphologischer merkmale bei Populus deltoides Bartr. Silvae Genet. 10: 161-177. (In German)
  • Marks, P. L. 1975. On the relation between extension growth and successional status of deciduous trees of the northeastern United States. Bull. Torrey Bot. Club 102: 172-7.
  • Marty, T. L. 1984. Population variability and genetic diversity of eastern cottonwood (Populus deltoides Bartr.). M.S. Thesis Univ. Wisconsin, Madison64 p.
  • Matzke, E. B. 1936. The effect of street lights in delaying leaf-fall in certain trees. Amer. J. Bot. 23: 446-52.
  • McCormac, J. S. 1993. Swamp cottonwood, Populus heterophylla, in Ohio. Michigan Bot. 32: 35-9.
  • McGee, A. B.; Schmierbach, M. R.; Bazzaz, F. A. 1981. Photosynthesis and growth in populations of Populus deltoides from contrasting habitats. Amer. Midl. Naturalist 105: 305-11.
  • McKnight, J. S. 1971. Cottonwood (Populus species).
  • McMaster, R. T. 2003. Populus heterophylla (swamp cottonwood) conservation and research plan for New England.
  • Mehrhoff, L. J. 1985. Notes on the flora of Connecticut -I. The Salicaceae of Connecticut. Newsletter Conn. Bot. Soc. 13(March): 9-12.
  • Meikle, R. D. 1984. Willows and poplars of Great Britian and Ireland. Botanical Society of the British Isles, London. , 198 pages. (Despite title, covers many species found in the northeastern USA)
  • Meirmans, P. G. et.al. 2010. Complex patterns of hybridization between exotic and native North American poplar species. Amer. J. Bot. 97: 1688-1697.
  • Miller, G. L. 1977. Early plant succession on a dredging spoils island in the Seneca River of upstate New York. Bull. Torrey Bot. Club 104: 386-391. (58 spp.)
  • Mitton, J. B.; Grant, M. C. 1980. Observations on the ecology and evolution of quacking aspen, Populus tremuloides, in the Colorado Front Range. Amer. J. Bot. 67: 202-9.
  • Mitton, J. B.; Grant, M. C. 1996. Genetic variation and the natural history of quaking aspen. The ways in which aspen reproduces underlie its great geographic range, high levels of genetic variability, and persistence. Bioscience 46(1): 25-31.
  • Morley, P. M.; Balatinecz, J. J. 1993. Poplar utilization in Canada: past, present and future. Forest. Chron. 69: 46-52.
  • Morris, D. M.; Farmer, R. E. 1985. Species interactions in seedling populations of Populus tremuloides and Populus balsmifera: effects of density and species ratios. Canad. J. Forest Res. 15: 593-5.
  • Moss, E. H. 1938. Longevity of seed and establishment of seedlings in species of Populus. Bot. Gaz. 99: 529-42.
  • Nagaraj, M. 1952. Floral morphology of Populus deltoides and P. tremuloides. Bot. Gaz. 114: 222-243.
  • Newhouse, M. E.; Madgwick, H. A. I. 1968. Comparative seedling growth of four hardwood species. Forest Sci. 14: 27-30.
  • Nimkar, A. U. et.al. 2002. Three decades of research on properties and utilization of Populus deltoides: A review. Indian Forester 128: 1254-1261.
  • Palik, B.J.; Pregitzer, K. S. 1995. Varibility in early height growth rate of forest trees: implications for retrospective studies of stand dynamics. Canad. J. Forest Res. 25: 767-76. (French summary)
  • Pauley, S. S. 1949. Forest-tree genetics research: Populus L. Econ. Bot. 3: 299-330.
  • Pauley, S. S. 1948. Sex and vigor in Populus. Science 108: 302-3.
  • Pauley, S. S. 1956. Natural hybridization of the aspens.
  • Pauley, S. S.; Perry, T. O. 1954. Ecotypic variation of the photoperiodic response in Populus. J. Arnold Arbor. 35: 167-88.
  • Pautov, A. A. 1992. The structure and growth of petiole in annual shoot metameres of {Populus alba L. (Salicaceae) with long and short internodes. Vest. Leningrad Univ., Biol. 1992: 105-106. (In Russian)
  • Pautov, A. A. et.al. 2002. Leaf epidermis microrelief in Populus (Salicaceae). Bot. Zhurn. St. Petersburg 87: 63-71. (In Russian)
  • Pautov, A. A. et.al. 2003. On similarity of the leaf epidermis structure in representatives of Flacourtiaceae and Salicaceae. Bot. Zhurn. St. Petersburg 88: 84-87. (In Russian)
  • Pearson, L. C.; Lawrence, D. B. 1958. Photosynthesis in aspen bark. Amer. J. Bot. 45: 383-7.
  • Pearson, L. C.; Lawrence, D. B. 1960. Photosynthesis in aspen bark during winter months. Proc. Minnesota Acad. Sci. 25-26: 101-7.
  • Peltzer, D. A.; Wilson, S. D. 2006. Hailstorm damage promotes aspen invasion into grassland. Canad. J. Bot. 84: 1142-1147.
  • Penfold, C. S. 1991. Genetic variation in traits affecting the water relations of balsam poplar along a latitudinal transect in northwestern Ontario. M.S. Thesis Lakehead Univ., Thunder Bay, Ontario62 p.
  • Perala, D. A.; Carpenter, E. M. 1985. Aspen (Populus tremuloides Michx. and P. grandidentata Michx.).
  • Peto, F. H. 1938. Cytology of poplar species and natural hybrids. Canad. J. Res., Sect. C, Bot. Sci. 16: 445-55.
  • Pollard, D. F. W. 1970. The effect of rapidly changing light on the rate of photosynthesis in largetooth aspen (Populus grandidentata). Canad. J. Bot. 48: 823-9.
  • Prachar, R. E.; Samuel, D. E. 1988. Influence of white-tailed deer browsing on mortality and growth of regenerating aspen. Trans. NE Sec. Wildlife Soc. 45: 27-36.
  • Pregitzer, K. S. et.al. 2002. Fine root architecture of nine North American trees. Ecol. Monogr. 72: 293-309.
  • Pregitzer, K. S.; Barnes, B. V. 1980. Flowering phenology of Populus tremuloides and P. grandidentata and the potential for hybridization. Canad. J. Forest Res. 10(2): 218-23.
  • Puettmann, K. J.; Reich, P. B. 1995. The differential sensitivity of red pine and quaking aspen to competition. Canad. J. Forest Res. 25(11): 1731-7.
  • Rajora, O. P. 1989. Pollen competition among Populus deltoides Marsh., P. nigra L. and P. maximowiczii Henry in fertilizing P. deltoides ovules and siring its seed crop. Sexual Pl. Reprod. 2(2): 90-6.
  • Rajora, O. P. 1990. Genetics of allozymes in Populus deltoides Marsh., P. nigra and P. maximowiczii Henry. J. Heredity 81: 301-8.
  • Rajora, O. P.; Dancik, B. P. 1992. Chlorplast inheritance in Populus. Theor. Appl. Genet. 84: 280-5.
  • Rajora, O. P.; Dancik, B. P. 1992. Genetic characterization and relationships of Populus alba, Populus tremula, and Populus x canescens and their clones. Theor. Appl. Genet. 84: 291-298.
  • Rajora, O. P.; Zsuffa, L.; Dancik, B. P. 1991. Allozyme and leaf morphological variation of eastern cottonwood at the northern limits of its range in Ontario. Forest Sci. 37: 688-702.
  • Regehr, D. L.; Bazzaz, F. A.; Boggess, W. R. 1974. Photosynthesis, transpiration, and leaf conductance of Populus deltoides in relation to flooding and drought. Photosynthetica 9: 52-61.
  • Richards, J. H.; Larson, P. R. 1981. Morphology and development of Populus deltoides branches in different environments. Bot. Gaz. 142: 382-393.
  • Rockwood, D. L. 1968. Variation within eastern cottonwood along the course of the Mississippi River. M.S. Thesis Univ. Illinois, Urbana50 p.
  • Roden, J. S.; Pearcy, R. W. 1993. Effect of leaf flutter on the light environment of poplars. Oecologia 93: 201-7.
  • Roden, J. S.; Pearcy, R. W. 1993. Photosynthetic gas exchange response of poplars to steady-state and dynamic light environments. Oecologia 93(2): 208-14.
  • Rogstad, S. H.; Nybom, H.; Schall, B. A. 1991. The tetrapod DNA fingerprinting M13 repeat probe reveals genetic diversity and clonal growth in quaking aspen (Populus tremuloides, Salicaceae). Pl. Syst. Evol. 175: 115-23.
  • Ronald, W. G. 1982. Intersectional hybridization of Populus sections Leuce-Aigeiros and Leuce-Tacamahaca. Silvae Genet. 31: 94-9.
  • Ronald, W. G.; Lenz, L. M.; Cumming, W. A. 1973. Biosystematics of the genus Populus L. I. Distribution and morphology of native Manitoba species and variants. Canad. J. Bot. 51(12): 2431-42.
  • Ronald, W. G.; Lenz, L. M.; Cumming, W. A. 1973. Biosystematics of the genus Populus L. II. Chemotaxonomy, phenology, fertility, and segregates of native Manitoba species and variants. Canad. J. Bot. 51(12): 2443-50.
  • Rouleau, E. 1948. Two new names in Populus. Rhodora 50(597): 233-6. (See correction in Rhodora 51(607):149-150. 1949.)
  • Rouleau, E. 1946. Populus balsamifera of Linnaeus not a nomen ambiguum. Rhodora 48: 103-10.
  • Rowland, D. L. et.al. 2002. A rare occurrence of seed formation on male branches of the dioecious tree, Populus deltoides. Amer. Midl. Naturalist 147: 185-187.
  • Russin, W. A.; Evert, R. F. 1984. Studies on the leaf of Populus deltoides (Salicaceae): Morphology and anatomy. Amer. J. Bot. 71(10): 1398-415.
  • Sakai, A. K.; Sharik, T. L. 1988. Clonal growth of male and female bigtooth aspen (Populus grandidentata). Ecology 69: 2031-3.
  • Sala, F.; Wang, G.; Castiglione, S.; Bisoffi, S. 1998. RAPD fingerprinting as a tool for taxonomic studies in the genus Populus. In: Molecular tools for screening biodiversity: plants and animals. Chapman & Hall, London. , 449-55 pages.
  • Sanchez, N. et.al. 1998. RAPD markers for the identification of Populus species. Silvae Genet. 47: 67-71.
  • Sandberg, D. 1951. The regeneration of quaking aspen by root suckering. M.S. Thesis Univ. Minnesota, Minneapolis, Minn.,
  • Santamour, F. S. 1956. Hermaphroditism in Populus.
  • Sargent, C. S. 1919. Notes on North American trees, V. J. Arnold Arbor. 1: 61-5.
  • Sawidis, T. et.al. 1995. A study of air pollution with heavy metals in Thessaloniki City (Greece) using trees as biological indicators. Arch. Environ. Contam. Toxicol. 28: 118-124.
  • Schier, G. A. 1973. Origin and development of aspen root suckers. Canad. J. Forest Res. 3: 45-53.
  • Schnekenburger, F.; Farmer, R. E. 1989. Genetic variation in growth of balsam poplar under 16- and 8-hour photosythetic periods. Forest Sci. 35: 903-19.
  • Schramm, J. R. 1966. Plant colonization studies on black wastes from anthracite mining in Pennsylvania. Trans. Amer. Philos. Soc. 56: 1-194.
  • Schreiner, E. J. 1970. Genetics of eastern cottonwood.
  • Searcy, K. B.; Ascher, R. 2001. The first record of Populus heterophylla (swamp cottenwood, Salicaceae) in Massachusetts. Rhodora 103: 224-226.
  • Segelquist, C. A.; Scott, M. L.; Auble, G. T. 1993. Establishment of Populus deltoides under simulated alluvial groundwater declines. Amer. Midl. Naturalist 130: 274-85.
  • Sentsov, M. F. et.al. 1995. Anatomical structure of bud scales in some species of the genus Populus L. Rastitel'nye Resursy 31: 89-93. (In Russian)
  • Shafroth, P. B.; Auble, G. T.; Scott, M. L. 1995. Germination and establishment of the native plains cottonwood (Populus deltoides Marshall subsp. monilifera) and the exotic Russian-olive (Elaeagnus angustifolia L.). Conserv. Biol. 9(5): 1169-75.
  • Slabaugh, P. E. 1958. Silvical characteristics of bigtooth aspen (Populus grandidentata).
  • Smith, E. C. 1943. A study of cytology and speciation in the genus Populus L. J. Arnold Arbor. 24: 275-305.
  • Smith, E. C.; Nichols, C. 1941. Species hybrids in forest trees. J. Arnold Arbor. 22: 443-54.
  • Smith, R. L. 1988. Phylogenetics of Populus L. (Salicaceae) based on restriction site fragment analysis of cpDNA. M.S. Thesis Univ. Wisconsin, Madison115 p.
  • Smith, R. L.; Sytsma, K. J. 1990. Evolution of Populus nigra (sect. Aigeiros): introgressive hybridization and the chloroplast contribution of Populus alba (sect. Populus). Amer. J. Bot. 77(9): 1176-87.
  • Sokal, R. R.; Crovello, T. J.; Unnasch, R. S. 1986. Geographic variation of vegetative characters of Populus deltoides. Syst. Bot. 11: 419-32.
  • Spies, T. A.; Barnes, B. V. 1981. A morphological analysis of Populus alba, P. grandidentata and their natural hybrids in southeastern Michigan. Silvae Genet. 39(2-3): 102-6.
  • Spies, T. A.; Barnes, B. V. 1982. Natural hybridization between Populus alba and the native aspens in southeastern Michigan. Canad. J. Forest Res. 12: 653-60.
  • Spurr, S. H.; Barnes, B. V. 1980. Forest Ecology. ed. Wiley, New York.
  • Squires, E. R.; Klosterman, J. E. 1981. Spatial patterning and competition in an aspen-white pine successional system. Amer. J. Bot. 68(6): 790-4.
  • Steneker, G. A. 1974. Factors affecting the suckering of trembling aspen. Forest. Chron. 50: 32-4.
  • Stettler, R. F.; Bradshaw, H. D.; Heilman, P. E.; Hinckley, T. M. (eds.) (1996): 1996. Biology of Populus and its implications for management and conservation. NRC Research Press, Ottawa, Ontario, Canada. , 539 pages. (NRC No. 40337; ISBN 0660165066)
  • Stoehr, M. U.; Singh, R. S. 1993. Restriction map and polymorphisms of nuclear ribosomal genes of Populus balsamifera. Tree Physiology 12: 419-425.
  • Strain, B. R.; Johnson, P. L. 1963. Cortical photosynthesis and growth in Populus tremuloides. Ecology 44: 581-4.
  • Tang, Z. 1988. Geographic variation and genetic parameters for growth and stem form of five-year-old eastern cottonwood from the southern United States. M.S. Thesis Mississippi State Univ., MS77 p.
  • Tappeiner, J. C. 1982. Aspen root systems and suckering in red pine stands. Amer. Midl. Naturalist 107: 408-10.
  • Taylor, J. L. 2001. Populus deltoides. Fire Effects Information System, [Online].
  • Tew, R. K. 1970. Seasonal variation in the nutrient content of aspen foliage. J. Wildl. Managem. 34: 475-8.
  • Thiebaut, M. 2000. A foliar morphometric approach to the study of Salicaceae. Bot. Rev. 66: 423-439.
  • Tidestrom, I. 1911. Populus virginiana Fouger. Rhodora 13: 195-199.
  • Tidestrom, I. 1914. Notes on the flora of Maryland and Virginia II. Rhodora 16: 201-209.
  • Tirmenstein, D. A. 1988. Populus tremuloides. ()
  • Tobiessen, P.; Kana, T. M. 1974. Drought-stress avoidance in three pioneer tree species. Ecology 55(3): 667-70.
  • Tormo, M. R. 1996. Pollen production in anemophilous trees. Grana 35: 38-46.
  • Tyree, M. T.; Cheung, Y. N. S.; MacGregor, M. E.; Talbot, A. J. B. 1978. The characteristics of seasonal and ontogenetic changes in the tissue-water relations of Acer, Populus, Tsuga, and Picea. Canad. J. Bot. 56(6): 635-47.
  • Verry, E. S.; Timmons, D. R. 1976. Elements in leaves of a trembling aspen clone by crown position and season. Canad. J. Forest Res. 6: 436-40.
  • Villar, M.; Gaget, M.; Dumas, C. 1986. Sexual reproduction biology in Populus, compatability and incompatability. In: Biotechnology and ecology of pollen. Springer-Verlag, Berlin. ,
  • Volin, J. C.; Tjoelker, M. G.; Oleksyn, J.; Reich, P. B. 1993. Light environment alters response to ozone stress in seedlings of Acer saccharum Mrsh. and hybrid Populus L. II. Diagnostic gas exchange and leaf chemistry. New Phyt. 124: 637-46.
  • Vozzo, J. A.; Hacskaylo, E. 1974. Endo- and ectomycorrhizal associations in five Populus species. Bull. Torrey Bot. Club 101: 182-6.
  • Wagner, W. H. 1970. The Barnes hybrid aspen, Populus x barnesii, hybr. nov. a nomenclatural case in point. Michigan Bot. 9: 53-4. (P. tremuloides x P. grandidentata)
  • Wall, R. E. 1971. Variation in decay in aspen stands as affected by their clonal growth pattern. Canad. J. Forest Res. 1: 141-6.
  • Wang, D.; Karnosky, D. F.; Bormann, F. H. 1986. Effects of ambient ozone on the productivity of Populus tremuloides Michx. grown under field conditions. Canad. J. Forest Res. 16: 47-55.
  • Watson, S. R. 1990. Frost hardiness of balsam poplar (Populus balsamifera L.) during the spring dehardening period. M.S. Thesis Lakehead Univ., Thunder Bay, Ontario125 p.
  • Wildman, H. G.; Parkinson, D. 1981. Seasonal changes in water-soluble carbohydrates of Populus tremuloides leaves. Canad. J. Bot. 59: 862-9.
  • Willing, R. R.; Pryor, L. D. 1976. Interspecific hybridization in poplars. Theor. Appl. Genet. 47: 141-51.
  • Willms, Jennifer et.al. 1998. Branch growth of riparian cottonwoods: a hydrologically sensitive dendrochronological tool. Trees 12: 215-223.
  • Wolken, J. M. et.al. 2010. Differences in initial root development and soil conditions affect establishment of trembling aspen and balsam poplar seedlings. Botany 88: 275-285.
  • Wood, C. D. 1994. A most dangerous tree: the Lombardy Poplar in landscape gardening. Arnoldia (Jamaica Plain) 54: 24-30.
  • Woolward, F. H. 1907. The germination of poplars. J. Bot. 45: 417-9.
  • Wright, J. W. 1952. Pollen dispersion of some forest trees.
  • Wright, J. W. 1953. Pollen dispersion studies: some practical applications. J. Forest. 51: 114-8.
  • Wu, R. L. et.al. 2000. An integrated genetic map of Populus deltoides based on amplified fragment length polymorphisms. Theor. Appl. Genet. 100: 1249-1256.
  • Ying, C. C.; Bagley, W. T. 1977. Variation in rooting capability of Populus deltoides. Silvae Genet. 26: 204-7.
  • Yu, C. Y. et al. et.al. 1990. Cladistic analysis of Populus. Bull. Bot. Res. Northeast. Forest. Inst. 10(1): 69-75. (In Chinese; English summary)
  • Yuceer, C. et.al. 2003. Shoot morphogenesis associated with flowering in Populus deltoides (Salicaceae). Amer. J. Bot. 90: 196-206.
  • Zahner, R.; Debyle, N. V. 1965. Effect of pruning the parent root on growth of aspen suckers. Ecology 46: 373-5.
  • Zasada, J. C.; Densmore, R. 1979. A trap to measure Populus and Salix seedfall. Canad. Field-Naturalist 93: 77-9.
  • Zhang, Q.; Yu, C. 1992. Study on the leaf epidermal structure of the genus Populus and its systematic significance. In: Advances in plant taxonomy in northwest China. Scientific and Technological Literature Press, Beijing. , 63-8 pages. (In Chinese; English summary)
  • Zimmermann, M. H.; Jeje, A. A. 1981. Vessel-length distribution in stems of some American woody plants. Canad. J. Bot. 59: 1882-1892.
  • Zsuffa, L. 1973. A summary review of interspecific breeding in the genus Populus.
  • van Broekhuizen, I. J. T. M. 1977. The genus Populus: taxonomy and a survey of the principal species. Dendroflora 13-14: 40-9. (In Danish; English summary)
  • van der Schoot, J. et.al. 2000. Development and characterization of microsatellite markers in black poplar (Populus nigra L.). Theor. Appl. Genet. 101: 317-322.