296 UKTICACE^I. 



2. LIPPIA, Houston. Ours low riparian herbs, bearing axillary 

 peduncled and braoted capitate spikes of small whitish flowers in char- 

 acter much like those of Verbena. Ovary 2-celled, in fruit forming 2 

 one-seeded nutlets. 



1. L. nodiflora, Michx. Erect, from creeping rootstocks, herbaceous 

 throughout Bead, rather slender: leaves oblanceolate or cuneate-spatulate, 

 serrate above: peduncles exceeding the leaves. — Muddy banks of the 

 lower Sacramento and San Joaquin. 



2. L. cnueifolia (Torr.), Steud. Woody at base and diffusely branch- 

 ing, the branches often a yard long or more, rather rigid and coarse: 

 leaves rigid, linear-cuneiform, incisely 2 — 6- toothed above the middle: 

 peduncles usually shorter than the leaves; bracts rigid, broadly cuneate, 

 abruptly acuminate. — River banks, and low subsaline plains of the 

 interior. 



Division V. APETAL^J AMENTIFER^!. 



Apetalous; mostly shrubs and trees with unisexual flowers; the stam- 

 inate always (except in the first two orders), and often the pistillate also, 

 in aments or catkins. 



Obdee lxxx. URTICACE£. 



Eepresented by very few species of two closely allied genera of herba- 

 ceous plants. 



1. URTICA, Pliny. Perennials; the quadrangular stems and other 

 parts bearing stinging bristly hairs. Leaves opposite, stipulate, serrate. 

 Flowers monoecious or dioecious, green, clustered in ament-like axillary 

 geminate racemes. Staminate fl. of 4 sepals, 4 stamens, and the cup- 

 shaped rudiment of an ovary; pistillate with 4 sepals, 2 outer spreading, 

 2 inner erect, the latter becoming membranous and enclosing the ovate 

 flattened achene. Stigma sessile, capitate, tufted. 



* Annual; inflorescence of mingled fl. of both sexes. 



1. U. ukens, Eay (1660). Slender, erect or ascending, 1—2 ft. high, 

 nearly glabrous: leaves thin, 1 — 2 in. long, ovate or ovate-oblong, very 

 coarsely and deeply toothed; stipules small, free: flower-clusters mainly 

 pistillate: fruiting sepals ovate, hispid on the margin, usually with one 

 lateral bristle: achene 1 line long. — Very common in sandy soil about 

 San Francisco, flowering all the year round. 



* * Perennials ; inflorescence unisexual. 



2. U. Cnlifornica, Greene. Stout but not tall, (2 — 3 ft. high), very 

 hispid: stipules large, narrowly oblong: leaves broadly or somewhat 



