EMPETRACE.E. (CROWBERRY FAMILY.) 487 



* * Petioles terete; bracts not silky ; stamens 12 -GO. 



3. P. heterophylla, L. (Downy Poplau.) Tree 40 - 80° high ; leaves 

 ovate with a soiiicwliat truiu-ate or cordate base, obtuse, crcnate, white-woolly 

 wlicu young, at length nearly smooth, except on tlie elevated veins beneath; 

 fertile catkins few-flowered; capsules -i' long, equalling the pedicels. — Bor- 

 ders of river swamps, Conn, to Ga., and iu the west from S. Ind. and HI. to 

 Ark. and W. La. 



§ 2. Stifles 2-4, irith dilated lobes; capsules large, often thick, subglobose to 

 vratc-oblon(j,2-4-ralre(l : bracts mostly glabrous ; seeds I -2'' long. 



4. P. balsamifera, L. (Balsam Poplar. Tacamaiiac.) Tree 50- 

 75° high, the large buds varnished with a copious fragrant resin ; leaves 

 ovate-lanceolate , graduallij tapering and pointed, finely crenate, smooth on both 

 sides, whitish and reticulately veined beneath, on terete petioles i - 2' long ; 

 scales dilated, slightly hairy ; stamens 20-30; capsule ovate, 2-valved. — Bor- 

 ders of rivers and swamps, N. New Eng. to Mich, and Minn., and far north 

 and westward. — Var. cAndicaxs, Gray. (Balm of Gilead.) Leaves broader 

 and more or less heart-shaped ; petiole commonly hairy. Common in cultiva- 

 tion, but rare or unkncjwu in a wild state. 



5. P. monilifera, Ait. (Cotton-wood. Necklace Poplar.) Tree 

 75-150° higli ; leaves broadly deltoid, with numerous crenate serratures and 

 narrow very acute acumination, sometimes ovate, rarely cordate, on elongated 

 flattened petioles; scales lacerate-friuged, not hairy; stamens 60 or more; cap- 

 sules on slender pedicels (4 - 5" long) in long catkins, oblong-ovate, 3 -A-valved. 

 (Incl. P. angulata. Ait.) — Borders of streams, western N. Eng. to Fla., west 

 to the Rocky Mts. 



Order 105. E3IPETRACEiE. (Crowberry Family.) 



Low shrubby evergreens^ icith the foliage, aspect, and compound pollen oj 

 Heaths, and the drupaceous fruit of Arctostaphylos, but the divided or 

 laciniate stigmas, etc., of some EJuphorbiacea? ; — probably only an apet- 

 alous and poly,L:;amous or dioecious degenerate form of Ericaceae, — com- 

 prising three genera, two of which occur within the limits of this work, 

 and the third farther south. 



1. Einpetrum. Flowers scattered and sohtjiry in the axils. Sepals 3, somewhat petal- 

 like. 

 - Corema. Flowers collected in terminal heads. Calyx none. 



1. EMPETRUM, Tourn. Crowbkrrv. 



Flowers polygamous, .scattered and solitary in the axils of tlie leaves (incon- 

 spicuous), scaly-bracteil. Calyx of 3 spreading and somewhat petal-like sepals. 

 Stamens 3. Style very short ; stigma 6 - 9-rayed. Fruit a berry-Hke drupe, 

 with 6-9 seed-like nutlets, each containing an erect anatropous seed. Embryo 

 terete, in the axis of copious albumen, with a slender inferior radicle and very 

 small cotyledons. (An ancient name, from iv, upon, and irerpos, a rock.) 



1. E. nigrum, L. (Black Crowberry.) Procumbent and spreading ; 

 leaves linear-oblong, scattered ; fruit black. — Newf., Mount Desert and 



