Populus balsamifera L. - Balsam Poplar, Black Poplar, Hackmatack, Tacamahac, Balm-of-Gilead
Common Names
Balsam Poplar, Black Poplar, Hackmatack, Tacamahac, Balm-of-GileadField Identification
Tree with simple, opposite leaves.Other uses
The use of poplars for removal and sequesterization of various heavy metals and other chemicals from contaminated soils (phytoremediation) has been explored.Nomenclature
Populus balsamifera L., Sp. Pl. 1034. 1753.
Populus tacamahacca Mill., Gard. Dict. ed. 8, P. no. 6. 1768.
Aigeiros balsamifera Lunell, Amer. Midland Nat. 4: 298. 1916.
TYPE: unknown
Rouleau, 1946Description
HABIT Perennial, deciduous, phanerophytic, tree, diclinous and dioecious, up to 30 m tall, forming a rounded crown; a lifespan 100 to 200 years old reported from out west (Fowells, 1965)(Burns & Honkala, 1990).
STEMS Main stems erect, round. Bark furrowed, smooth when young, not exfoliating, gray to dark gray. Branches erect or ascending. Twigs brown, not odoriferous, terete, 3-5 mm in diam., smooth, glabrous, eglandular. Pith brown, 5-pointed, continuous, nodal diaphragm absent. For a micro-anatomical study of the xylem (Gol'Traf, 1982 (In Russian)). For a synopsis of the root system see (Stettler et al, 1996).
BUDS Terminal and axillary present, monomorphic, scattered along stem; terminal bud ovoid, pointed, viscid; axillary buds 1 per axil, ovoid, pointed, viscid. Bud scales dark brown to brown, imbricate, glabrous, eglandular. Bud scale scars not encircling the stem. Leaf scars crescent-shaped. Vascular bundle scars 3, crescent-shaped. For a study of the anatomical structure of the bud scales see (Sentsov, 1995 (In Russian)).
LEAVES Alternate, simple, spiral, 1 per node, spaced somewhat evenly along and divergent from stem. Stipules present, caducous, lateral, free from the petiole, small, leaf-like. Leaves petiolate, petiole terete, 1.5-6 cm long, with long and unbranched white to light gray erect to spreading hairs, sparse or moderately dense, distributed throughout, eglandular. Leaf blades: abaxial surface light green (sometimes glaucous), adaxial surface green, ovate, bilaterally symmetric, 3-16 cm long, 2.5-11 cm wide, chartaceous, base cuneate to obtuse to sub-cordate, margin serrate and ciliate (margins also sometimes sun-entire and sometimes with minute glands at teeth); apex acuminate or acute. Abaxial surface glabrous or with long and unbranched erect or spreading, white or light gray, hairs, sparse or moderately dense, distributed throughout, eglandular (although often viscid and with dull-orange blotches and streaks). Adaxial surface glabrous or with long and unbranched erect or spreading, white or light gray hairs, sparsely distributed throughout, eglandular. For an overview of the secondary leaf tissues see (Stettler et al, 1996). The western phase (ssp. trichocarpa) with dimorphic early and late leaves (Critchfield, 1960).
FEMALE INFLORESCENCES Precocious, formed on last season's growth, unisexual, axillary raceme, greenish, pendant, catkin-like. Peduncle and rachis hairy. Bracts 1, subtending each flower, petiolate, adnate to pedicel, brown, apices erose and ciliate, lateral surfaces glabrous, eglandular. Pedicels 1-1.5 mm long, glabrous, eglandular.
FEMALE FLOWERS Perianth parts indistinguishable from one another, fragrance absent, Gynoecium set on perianth which is a crateriform disk composed of connate tepals (perigon). Perigon persistent, glabrous, eglandular. Carpels 2-4. Locules 1. Stigmas 2, lobed. Styles 1. Ovary superior, ovoid, glabrous, eglandular. Placentation parietal.
MALE INFLORESCENCES Precocious, formed on last season's growth, unisexual, axillary raceme, reddish-purple, pendant, catkin-like. Peduncle and rachis hairy. Bracts 1, subtending each flower, petiolate, adnate to pedicel, brown, apices erose and ciliate, lateral surfaces glabrous, eglandular. Pedicels 1-1.5 mm long, glabrous, eglandular.
MALE FLOWERS Perianth parts indistinguishable from one another, fragrance absent. Androecium set on perianth which is a crateriform disk composed of connate tepals (perigon). Perigon persistent, glabrous, eglandular. Stamens 10-50, exserted. Anthers glabrous, eglandular, dehiscing longitudinal. Filaments free, straight, glabrous, eglandular.
FRUITS Loculicidal 2-valved capsule, brown, ovoid, 5-8 mm long, glabrous, eglandular with 2-30 seeds per fruit. Age at reproductive maturity 8-10 years (Burns & Honkala, 1990).
SEEDS Minute, glabrous, eglandular; adnate tufts of "cotton" (which facilitate anemochory) composed of epidermal hairs of the placenta (Nagaraj, 1952). Endosperm completely consumed by developing embryo so that none remains in the mature seed (Nagaraj, 1952). Weight about .3 mg (Burns & Honkala, 1990).
Habitat
Alluvial bottoms, river flats, sand bars, stream banks, borders of swamps and lakes; sea level to 5,500 ft. elev. Not shade tolerant; found in all but the most wet or dry soils. (Fowells, 1965)Distribution
Circumpolar, native to northern North America and northeastern Asia.
United States -- AK, CA(ssp. trichocarpa), CO, CT, DE?, IA, ID, IL, IN, MA, MD, ME, MI, MN, MT, ND, NE?, NH, NJ, NV(ssp. trichocarpa), NY, OH, OR, PA, RI?, SD, UT, VA?, VT, WA(ssp. trichocarpa), WI, WV, WY
Canada -- AB, BC, MB, NB, NF, NS, NT, ON, PE, QC, SK, YT
New York Metropolitan Region -- Native, found in the western and northern areas of the metropolitan region.
Rarity Status
Global Heritage Rank -- G5
Connecticut -- Not listed
New Jersey -- Not listed
New York -- Not listed
Species Biology
Flowering
April - May
Pollination
Anemophily
Fruiting
May
Dispersal
Anemochory and Hydochory (Stettler et al, 1996).
Germination
It is difficult to define germination with the small seeds of Populus species; for most species; germinated seedlings should have well-developed hypocotyl hairs, regular growth, and a geotropic response. Seeds that have been dried for storage may suffer injury from rapid imbibition; aeration with humid air after storage has been used to solve this problem. The critical factor for germination is moisture. (Young & Young, 1992) The time of ripening is quite variable; a safe criterion for time of fruit collection is when a small percentage of the capsules are beginning to open. Pre-strorage drying immediately after collecting is essential for successful storage. A moisture content of 5-8% improves viability and germination of stored seed. After air drying for 4 days store in a sealed container at 41d F. The critical factor for germination is moisture. (Dirr & Heuser, 1987)
Germination immediately after dispersal on moist bare soil, viable for only a few days. (Fowells, 1965)(Burns & Honkala, 1990).
Optimum pH 6-8 (Burns & Honkala, 1990).
Long term viability can be maintained with temperatures below freezing in a dry atmosphere. (Stettler et al, 1996).
Also regenerates readily from roots suckers and stump sprouts. (Fowells, 1965)
Reportedly hybridizes with P. alba, P. deltoides, & P. nigra. (Fowells, 1965)