ORDER CIX. URTICACEJi. 501 



long petioles. Flowers monoBcious, in clustered corymb?. Stamens 

 usually 3. — @. July. Wet grounds, 6 — 12 inches. 



2. U. u'rens, (L.) Stem erect, quadrangular, hairy, hispid. Leavrn 

 opposite, elliptic, 3-nerved, or partly 5-nerved, coarsely toothed, with 

 white stings. Spikes glomerate, by pairs. Flowers clustered. — Q. 

 June — July. Cultivated grounds. Stinging Nettle. 



3. U. CHAMiEDROi'DES, (Pursli.) Stem erect, glabrous. Leaves oppo- 

 site, ovate, hairy beneath, with white stings on the upper surface. 

 Flowers in axillary clusters, the upper ones fertile, the lower sterile. 

 Perianth hairy. — 0. Feb. — March. Southern Geo. 4 — 6 inches. 



4. U. Dioi'cA, (L.) Stern erect, branching, hispid. Leaves cordate, 

 ovate-lanceolate, coarsely serrate. Flowers dioecious, in clustered, pa- 

 niculate spikes; spikes 2 from each axil, covered with stingy. — If. 

 June — Aug. Waste places. 2 — 3 feet. Large Stinging Nettle. 



5. U. proce'ra, (Muhl.) Stem erect, pubescent, quadrangular. Leaves 

 ovate-lanceolate, serrate, on fringed petioles. Flowers dioecious, in com- 

 pact, clustered spikes. — If. July — Aug. Wet soilg. 3 — 4 feet. 



6. U. capita'ta, (L.) Stent erect, furrowed, quadrangular. Leaves 

 alternate, cordate-ovate, acuminate, serrate, 3-nerved. Flowers in ses- 

 sile clusters. Spikes solitary, lateral, and axillary. — If. June — July. 

 Damp soils. 4 — 5 feet. 



7. U. divarica'ta, (L.) Ste7n erect, branching, covered with stings. 

 Leaves alternate, ovate, acuminate, smooth, serrate, on long, ciliate pe- 

 tioles. Panicles axillary, solitary, divaricately branched. — 2^. July — 

 Aug. Damp rocky situations. 2 — 3 feet. 



8. U. Canaden'sis, (L.) Stetn erect, branching, hispid, with stings. 

 Leaves alternate, cordate-ovate, acuminate, hispid. Floicersin axilhiry 

 panicles; the lower ones sterile, the upper fertile. — U. July — Aug. 

 Wet soils. Mountains. 2 — 3 feet. 



Genus II.— BCEHME'RIA. Jacq. 19—4. 

 (In honor of Boehmer, a German botenist.) 



Monoecious or dioecious. Sterile florets ; perianth 4-parted. 

 Stamens 4. Fertile florets ; perianth none. Sti/le 1. Nut 

 compressed. 



1. B. cylin'drica, (L.) Stem obtusely 4-angled, glabrous. Leaves 

 opposite, ovate-oblong, acuminate, dentate, smooLh. Flowers d'u:ec\ou'». 

 Sterile spikes clustered, interrupted; fertile ones cylindrical. — If. 

 June — Aug. Wet grounds. 2 — 3 feet. 



2. B. lateriflo'ra, (Mich.) Stem smooth, with opposite branches. 

 Leaves alternate, ovate-lanceolate, acuminate, serrate, scabrous, on long 

 petioles, jp'/owrs in lateral and axillary clusters. — If. July. Shady 

 woods. 



The Cannabis sativa, the common hemp, altliough an exotic, has escaped from 

 cultivation, and often lines the road-side. 



Genus III.— PARIETA'RIA Tourn. 19—4. 

 (From paries, a wall, the usual place of its growth.) 



Flowers monoecious or polygamous, surrounded by a niauy- 

 cleft involucre. Perfect florets ; perianth 4-ok'ft. Stamens 4. 



