URTICACEAE. 



Vol. I. 



4. Urtica chamaedryoides Pursh. 

 Weak Nettle. Fig. 1559. 



Urtica chamaedryoides Pursh, Fl. Am. Sept. 113. 

 1814. 



Annual, sparingly stinging-bristly but other- 

 wise nearly or quite glabrous, stem very 

 slender, weak, ascending, simple or branched, 

 6'-3° long. Leaves slender-petioled, thin, 

 crenate-dentate, the lower broadly ovate or 

 orbicular, obtuse at the apex and usually cor- 

 date at the base, i'-ii' wide, the upper ovate 

 or lanceolate, acute or acuminate at the apex, 

 rounded or narrowed at the base, the upper- 

 most very small ; stipules lanceolate-subulate ; 

 flower-clusters small, glomerate, shorter than 

 the petioles ; flowers androgynous. 



In thickets, Kentucky to Arkansas, south to 

 Georgia and Texas. April-Aug. 



2. URTICASTRUM Fabr. Enum. 

 204. 1759- 

 [Laportea Gaud, in Freyc. Voy. Bot. 498. 1826.] 

 Perennial herbs, armed with stinging hairs, the leaves broad, alternate, serrate, petioled, 

 the flowers monoecious or dioecious, sessile in loose axillary compound cymes. Staminate 

 flowers in our species with 5 imbricated sepals, 5 stamens and a rudimentary ovary. Pistil- 

 late flowers with 4 unequal sepals, the outer 1 or 2 minute, an oblique or nearly straight com- 

 pressed ovary and a subulate slender persistent style; ovule erect. Achene very oblique, 

 flat, reflexed. Seed-coat membranous. Endosperm scanty or wanting. [Latin, star nettle.] 

 About 25 species, mostly of tropical distribution, only the following, the generic type, North 

 American. 



i. Urticastrum divaricatum (L.) Kuntze. 

 Wood or Canada Nettle. Fig. 1560. 



Urtica divaricata L. Sp. PI. 985. 1753. 



Urtica canadensis L. Sp. PI. 985. 1753- 



Laportea canadensis Gaud, in Freyc. Voy. Bot. 498. 1826. 



U. divaricatum Kuntze, Rev. Gen. PL 635. 1891. 



Stem rather stout, erect or ascending, ii°-4° tall. 

 Leaves thin, ovate, long-petioled, acuminate or acute 

 at the apex, sharply serrate, 3-nerved and pinnately 

 veined, glabrous or with some stinging hairs, 3'-%' 

 long, a'-s' wide; petioles very slender, ii-5' long; 

 stipule solitary, small, lanceolate, 2-cleft, commonly 

 deciduous ; flower-clusters large and loose, often 

 longer than the petioles, the lower staminate, the 

 upper pistillate, divergent, 2'-6' broad in fruit; ulti- 

 mate branches of the fruiting clusters flat, cuneate, 

 emarginate ; achene twice as long as the calyx, gla- 

 brous, lb" long. 



In rich woods, Nova Scotia to Ontario and North Da- 

 kota, south to Florida and Kansas. Ascends to 3000 ft. in 

 the Adirondacks. July-Aug. Albany-hemp. 



3. PILEA Lindl. Coll. pi. 4. 1821. 

 [AnfcEA Raf. Ann. Nat. 179. Hyponym. 1815.] 

 Annual or perennial, glabrous or pubescent stingless herbs, with opposite petioled 

 mostly 3-nerved leaves, connate stipules, and small numerous monoecious or dioecious flow- 

 ers in axillary cymose or glomerate clusters. Staminate flowers mostly 4-parted (sometimes 

 2- or 3-parted) and with a rudimentary ovary. Pistillate flowers 3-parted, the segments, in 

 most species unequal, each subtending a staminodium in the form of a concave scale; ovary 

 straight; stigma sessile, penicillate. Achene compressed, ovate or suborbicular. Seed-coat 

 thin. Endosperm scanty or noner [Name referring to the larger sepal of the type species 

 which is something like a cap.] 



About 200 species, chiefly in the tropics, most abundant in tropical America. Besides the follow- 

 ing, another occurs in the southern United States. Type species : Pilea muscdsa Lindl. 



