URTICACEAE. 



Alnus tenuifolia Nutt. Small tree, 5-10 m. tall; bark whitish even on the 

 twigs; budfl pubescent; leaves ovate or somewhat obovate, mostly obtuse, 

 rounded <>r subcordate a1 the base, with a small lobe at the end of each vein, 

 dentate-serrate, dull-green, 3-8 cm. long, sparsely pubescent on both sides, 

 J.ibnuis above; petioles stout, pubescent, 1-1.5 cm. long; fruiting 

 am. d1 a i ivate, 1-2.5 cm. long, resinous, with shorter peduncles. Along streams, 

 not r.irv. 



Family 26. ULMACEAE. Elm Family. 



Trees or shrubs; leaves alternate, simple, serrate or entire, 

 petioled, pinnately veined, with usually fugacious stipules; 

 flowers small, monoecious, dioecious, perfect or polygamous; 

 sepals 3-9, free or united; petals none; stamens as many as the 



pals and opposite them; ovary 1-celled; ovule one; fruit a 

 samara, drupe or nut. 



107. CELTIS. 



Trees or shrubs; leaves serrate or entire, pinnately veined; 

 flowers polygamous or monoecious, borne in the axils of the 

 mmsoii's leaves, the staminate clustered, the fertile solitary or in 

 2-3-flowered clusters; calyx 4-6-parted; ovary sessile; stigmas 

 2 , fruit an ovoid or globose drupe. 



Celtis douglasii Planch. Hackberry. Scraggly tree or shrub, 3-5 m. tall; 

 leaves oblique-ovate, acuminate, cuneate at the base, sharply serrate, pu- 

 bescent when young, glabrous and shiny above when mature, somewhat 

 pubescent on the veins beneath, rough, reticulated, 4-8 cm. long; petioles 

 about 1 cm. long; fruit reddish, globose, smooth, 5-7 mm. in diameter, on 

 ^!< nder peduncles, about 2 cm. long. Basaltic bluffs on Snake River; a hand- 

 some tree when grown in good soil, but under natural conditions very scraggly; 

 leaves often distorted as a result of insect attacks. 



Family 27. URTICACEAE. Nettle Family. 



Herbs (in ours); leaves alternate or opposite, simple, with or 

 without stipules; flowers small, monoecious, dioecious or polyg- 

 amous; calyx of 2-5 nearly separate sepals or cup-shaped; 

 petals none; stamens as many as the calyx-lobes and opposite 

 them; ovary 1-celled, mostly superior; ovule solitary; fruit an 

 akene; endosperm scanty or none. 



pposite, with stinging hairs. 108. Urtica, 78. 



iternatc, without stinging hairs. 109. Parietaria, 79. 



108. URTICA. Nettle. 



Annual or perennial simple or branching herbs with stinging 



■s; leaves opposite, 3-7-nerved, petioled, dentate or incised, 



With distinct stipules; flowers greenish, very small and numerous, 



