EMPETRACE^. (CROWBERRY FAMILY.) 487 



* * Petioles terete ; bracts not silky ; stamens 12-60. 



3. P. heterophylla, L. (Doavxy Poplar.) Tree 40 - 80° higli ; leaves 

 ovate witli a sonu'what truucate ur cordate base, obtuse, creuate, white-woollv 

 wheu youug, at length nearly smooth, except on tlie elevated veins beneath; 

 fertile catkins few-flowered; capsules 5' long, equalling the pedicels. — Bor- 

 ders of river swamps, Conn, to Ga., and in the west from S. lud. and 111. to 

 Ark. and AY. La. 



§ 2. Styles 2 - 4, with dilated lobes ; capsules large, ojien thick, subglobose t6 

 ovate-oblong, 2 — 4:-irdi'ed : bracts mostly glabrous ; seeds \~2'' long. 



4. P. balsaraifera, L. (Balsam Poplar. Tacamahac.) Tree 50- 

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

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

 sides, whitish and reticulately veined beneath, on terete petioles ^-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. candicans. Gray. (Balm of Gilead.) Leaves broader 

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

 tion, but rare or unknown in a wild state. 



5. P. naonilifera, Ait, (Cotton-wood. Necklace Poplar.) Tret 

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

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

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

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

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

 to the Rocky Mts. 



Order 105. EMPETRACE^. (Crowberry Family.) 



Low shrubby evergreens, with the foliage, aspect, and compound pollen oj 

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

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

 alous and polygamous or dioecious degenerate form of Ericaceae, — com- 

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

 and the third farther south. 



1. Empetrum. Flowers scattered and solitary in the axils. Sepals 3, somewhat petal- 

 like. 

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



1. EMPETRUM, Tourn. Crowberry. 



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

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

 fetamens 3. Style A^ery short ; stigma 6 - 9-rayed. Fruit a berry -like drupe, 

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

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

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



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

 leaves linear-oljlung, scattered ; fruit black. — Newf.. ^Nlount Desert and 



