SANTALACEAE (SANDALWOOD FAMILY) 77 



A". Perennial; herbage with stinging hairs; leaves opposite, coarsely serrulate; 



stipules present; flowers not involucrate. URTICA (p. 77) 



AA. Annual; herbage without stinging hairs; leaves alternate, entire; stipules 



none; flowers involucrate by leafy bracts. PARIETARIA l,p. 77) 



URTICA (Nettle) 



Herbs, tall. Stem 4-angled. Flowers small; clusters paired, racemes 

 or spikes or heads. Perianth 4-parted. Staminate flowers with 4 stamens 

 and a rudimentary ovary. — (L. urere = to bum ; referring to the sensa- 

 tion produced by the stinging hairs.) The stinging hairs produce intense 

 itching. 



A. Leaves soft-pubescent on both sides; staminate flower-clusters nearly equaling 



the leaves. E. U. holosericea (hairy nettle) 



AA. Leaves glabrous above or nearly so, sparsely pubescent beneath; staminate 



flower-clusters hardly exceeding the petiole. 



B. Inner perianth-segments rather widest below their middle, iu fruit shorter than 



the akene; akene i-i.s mm. long. W- C. E. U. lyallil (common nettle) 



BB. Inner perianth-segments rather widest above their middle, in fruit about 3 



times as long as the akene; akene 0.5-0.7 mm. long. W. C. E. U. breweri 



PARIETARIA (Pellitory) 



Herbs, low, diffuse or tufted. Flowers polygamous; clusters headlike, 

 involucrate by leafy bracts. Perianth of staminate flowers 4-parted or of 

 3-4 distinct segments. Perianth of pistillate and perfect flowers tubular 

 or campanulate, 4-lobed. — In dry open places. (L. paries = a wall ; 

 because some species prefer to grow on old walls.) 



A. Leaves oblong-lanceolate; involucre 2-3 times as long as the flowers. E. 



P. pennsylvanica 

 AA. Leaves ovate; involucre about equaling the flowers. W. E. P. debilis 



SANTALACEAE (Sandalwood Family) 



Herbs, sometimes root parasites. Leaves entire. Flowers per- 

 fect, mostly greenish. Perianth adnate to base of ovary or to disk. 

 Stamens as many as the perianth lobes and opposite them. Ovary 

 i-celled; placenta central; style o-i. Fruit a drupe. Seed i. 

 — Only the following genus. 



COMANDRA (Comandra) 



Perennial, erect, glabrous, mostly parasitic on the roots of other plants. 

 Leaves alternate, almost sessile. Flower clusters cymose, bractless. Per- 

 ianth campanulate, 4-s-lobed. Anthers attached to the calyx lobes each 

 by a tuft of hair. — (Gk. }tomn = hair, andros = a man or male ; referring 

 to the anther hairs.) 



