412 ITRTICACE^E. (NETTLE FAMILY.) 



with a single erect orthotropous ovule. Stigma simple or tufted. Ache- 

 nium commonly enclosed in the dry persistent calyx. Embryo straight, 

 in the axis of fleshy albumen. 



Synopsis. 



* Plants armed with stinging hairs. 



1. URTICA. Stamens 4. Stigma tufted. Achenium straight. 



2. LAPORTEA. Stamens 5. Stigma subulate. Achenium oblique. 



* * Plants destitute of stinging hairs. 



- Flowers in cymose clusters. 



3. PILEA. Clusters naked. Calyx-lobes unequal. Leaves opposite. 



4. PARIETARIA. Clusters involucrate. Calyx-lobes equal. Leaves alternate. 



i- -t- Flowers in spiked clusters. 

 6- BCEHMERIA. Stigmas subulate, leaves opposite or alternate. 



1. ITRTICA, Tourn. NETTLE. 



Flowers monoecious or dioecious. Calyx of the sterile flower 4-parted. Sta- 

 mens 4, inserted around the abortive ovary. Calyx of the fertile flower 4-sepa- 

 lous, unequal ; the inner ones dilated in fruit, and enclosing the achenium. 

 Stigma sessile, tufted. Achenium straight, ovate, smooth, compressed. Herbs, 

 with stinging hairs, opposite leaves, and greenish flowers, in panicled spikes or 

 close clusters. 



* Flowers in panicled or simple spikes, 



1. IT. gracilis, Ait. Stem tall, 4-angled, smoothish, slender ; leaves long- 

 petioled, ovate-lanceolate, coarsely serrate, acute, rounded at the base, 3-5- 

 nerved, smoothish, the petioles bristly ; spikes very slender, loosely panicled. 

 (U. procera, Willd.) Low ground in the upper districts, and northward. July 

 and Aug. 1|. Stem 3 - 4 high, mostly simple. Leaves thin, 4' -6' long. 



2. U. dioica, L. Hispid throughout; stem 4-angled, pubescent above, 

 branching ; leaves rather short-petioled, ovate, cordate, acuminate, coarsely ser- 

 rate, pubescent beneath ; spikes much branched ; flowers often dioecious. 

 Waste places. In Carolina, Pursh. Introduced. June -Aug. 1J. Stem 2- 

 3 high. Leaves 3' -4' long, thicker than in No. 1, and flowers larger. 



3. IT. capitata, Willd. Stem 4-angled, roughish ; leaves large, long- 

 petioled, rough, oblong-ovate, slightly cordate, coarsely serrate, 3-nerved ; those 

 on the branches alternate ; spike solitary, leafy at the summit. Wet shaded 

 places, North and South Carolina, Curtis, Elliott. July and Aug. Stem 3 - 

 5 high. 



# * Flowers in simple clusters shorter than the petioles. 



4. TJ. urens, L. Stem 4-angled, hairy ; leaves ovate, coarsely serrate, 

 5-nerved, hairy ; clusters by pairs in each axil, loose, peduncled. Damp soil. 

 Introduced. Dec. -Feb. (I) Stem 1 high. 



5. IT. Chamsedryoides, Pursh. Stem smooth ; leaves small, nearly ses- 

 sile, ovate, coarsely serrate, hairy beneath, hairy and bristly above; clusters 

 nearly sessile, globose, dense ; calyx hairy. St. Simon's Island, Georgia, 

 Elliott. Feb. and March. Stem 4' - 6' high. 



