FLOKA OF THE DISTRICT OF COLUMBIA. 215 



2. PROSEBPINACA L. 



1. Proserpinaca palustris L. Mermaid-weed. 



Shallow water; along the Potomac and near Bladensburg; infrequent. June- 

 July. Widely distributed in N. Amer. 



114. ARALIACEAE. Ginseng Family. 



Hedera helix L., English ivy, native of Eur, and common in cultivation, has occa- 

 sionally spread to roadsides or woods. 



Leaves whorled or opposite; leaflets usually 3 or 5 1. PANAX. 



Leaves alternate; leaflets numerous 2. ABALIA, 



1. PANAX L. 



Leaflets all slender-stalked, broadly obovate or oval, taper-pointed; roots long and 

 thick 1. P. quinquefolium. 



Leaflets, at least the lateral ones, sessile, mostly oblanceolate to oblong, obtuse or 

 acutish; roots globose 2. P. trlfolium. 



1. Panax quinquefolium L. Ginseng. 

 Rich woods; rare. July-Aug. Eastern N. Amer. (Aralia quinquefolia Decaisne & 



Planch.) 



The roots are much used in China for their supposed medicinal virtues, and the 

 plants are cultivated in the United States to obtain the roots for export. 



2. Panax trlfolium L. Groundnut. 

 Moist woods and thickets; occasional. Apr.-May. Eastern N. Amer. (Aralia 



trifolia Decaisne.) 



2. ABALIA L. 



Plants shrubby, armed with stout spines; leaflets thick, pale beneath 1. A. splnosa. 



Plants herbaceous, unarmed ; leaflets thin, green. 



Umbels of flowers numerous, in racemes or panicles; stems branched. 2. A. racemosa. 



Umbels of flowers 2-7, arranged in an umbel; stems simple 3. A. nudicaulls. 



1. Aralia spmosa L. Angelica tree. 

 Moist woods; infrequent. Aug.-Sept. Eastern U. S. 



Stems simple or branched, usually 3-5 meters high. Sometimes known as HerculeB' 

 club. 



2. Aralia racemosa L. Spikenard. 

 Rich woods; infrequent. July-Aug. Eastern N. Amer. 



The roots are used in medicine. 



3. Aralia nudicaulis L. Wild sarsaparilla. 

 Moist woods; frequent. May. Eastern N. Amer., westward to the Rocky Mte. 

 The roots are used as a substitute for the official sarsaparilla. 



115. APIACEAE. Parsley Family. 



Besides the genera listed below, the following plants of European origin have been 

 collected in our region, most of them as mere waifs: Bupleurum rotundifolium L. 

 (Washington, 1889, Coville); Carum carui L. t caraway (waste ground along the river 

 front, 1899, Steele, two plants found); Foeniculum vulgare Hill, fennel (reported by 

 Steele); Scandix pecten-veneris L. (waste ground, 1898, Steele); Seseli libanotis Koch 

 (Maryland Agricultural College, 1905, J. B. S. Norton, one plant found). 



Stem and basal leaves simple, not lobed. Flowers white or yellowish. 



Leaves linear or linear-oblong, at least some of them spine- toothed; flowers in 



dense heads 1. EBYNGIUM. 



Leaves rounded, not spine-toothed; flowers in umbels 15. HYDROCOTYLE. 



