52 ARACEAE. 



Scirpus atrovirens Muhl. Similar to S. microcarpus; stems taller, often 

 100-150 cm. high; panicle much denser; spikelets dark greenish-brown, ovoid 

 to cylindric, 3-8 mm. long, in heads of 10-30; scales acuminate; akene oblong- 

 obovoid, sharply pointed. Waitsburg, Horner. 



69. HEMICARPHA. 



Mostly annual, low tufted plants; stems and leaves erect or 

 spreading, almost filiform; spikelets terete, terminal, clustered or 

 solitary, subtended by a 1-3-leaved involucre; scales in a spiral, 

 deciduous, all subtending perfect flowers; perianth of a single 

 hyaline bract between the flower and the rachilla; bristles none; 

 stamens 1-3; style 2-cleft, deciduous, not swollen at the base; 

 akene oblong, turgid or lenticular. 



Hemicarpha aristulata (Coville) A. Nelson. Tufted, glabrous, the nu- 

 merous stems 5-8 cm. tall, erect or spreading; leaves narrow, involute, the 

 recurved blades 1-3 cm. long, as long as or longer than the sheaths; spikelets 

 ovoid, obtuse, solitary or two in a cluster, 2-4 mm. long; involucral bracts 3, 

 the uppermost 1-3 cm. long, the others much shorter; scales 1-1.5 mm. long, 

 broadly obovate, the abruptly-acuminate recurved apex as long as the body; 

 akene oblong, ovate or obovate, 0.5 mm. long, with a short beak, the surface 

 very minutely and regularly hexagonal-reticulate and rugose; styles shorter 

 than the akene, 2-cleft half-way to the base; hyaline bract triangular-ovate. 

 Very rare on the banks of Snake River at Almota. The species has the habit 

 of H. subsquarrosa Nees, but the heads of H. occidentalis Gray. 



Family 17. ARACEAE. Arum Family. 



Plants with acrid or pungent juice and simple or compound 

 leaves; flowers crowded on a spadix, perfect, monoecious or 

 dioecious; spathe present or none; perianth of 4-6 sepals or 

 none; fruit usually a 1-4-celled 1-seeded berry. 



70. LYSICHITON. 



Acaulescent swamp herbs with large leaves from a thick 

 horizontal rootstock; spathe sheathing at base, with or without 

 a broad colored lamina, at first enveloping the cylindrical spadix 

 which later becomes long-exserted on a stout peduncle; flowers 

 perfect, crowded, covering the spadix; perianth 4-lobed ; stamens 

 4, opposite the perianth-segments; ovary 2-celled, 2-ovuled; 

 fruit fleshy, somewhat immersed in the rachis and coalescent. 



Lysichiton camtschatcense (L.) Schott. Yellow Skunk Cabbage. Leaves 

 large, 30-90 cm. long, oblong, acute or acutish, narrowed at base into a short 

 margined petiole; spathe golden-yellow, the blade oblong, acute, narrowed into 

 a sheathing petiole; peduncle stout, 20-30 cm. long; spadix cylindric, in fruit 

 5-12 cm. long. In swamps, the brilliant malodorous flowers appearing before 

 the leaves. 



