92 SELECTED WESTEBN FLORA 



LVI. LOASACE^ (LoASA Family). 



Erect or cKmbing herbs armed with hooked or stinging hairs, with 

 alternate or opposite exstipulate leaves and regular perfect flowers 

 either solitary or clustered. Calyx 4r-5-cleft, its tube adhering to 

 the ovary; petals as many or twice as many as the divisions in the 

 ovary; stamens numerous, in clusters opposite the petals, inserted 

 with the petals; style entire or 2-3-lobed, ovary 1-celled, with 2 or 

 3 parietal placentae, and crowned with the persistent calyx teeth. 



1. MEWTZELIA. Bahtonia. 



Calyx 5-lobed; petals 5 or 10, spreading, deciduous; stamens 20 

 or more; styles 3, somewhat united; capsule few-seeded. Erect 

 herbs with alternate leaves and showy terminal flowers. 



,1. M. decapetala, (Pursh.) TJi-ban and Gilg. 



Stout, 1-2 ft. high, rough-pubescent ; leaves ovate to lanceolate, sinuate- 

 pinnatifid, the upper sessile, the lower petioled; flowers mostly soUtary, 

 yellowish white, opening in the evening. (M. ornata, T. and G.) Clay 

 banks, S. Alta. 



LVII. CACTACE^ (Cactus Family). 



Mostly leafless plants, the thickened fleshy stems usually covered 

 with prickles. Flowers sessile and solitary; sepals and petals 

 numerous, adhering to the tube formed by the union of petals and 

 sepals; ovary 1-celIed; style 1; stigmas many. 



1. MAMILLARIA. 



Globose or ovoid, covered with spine-bearing tubercles with the 

 flowers springing from woolly or bristly projections between the 

 tubercles. 



1. M. -vivlpara, (Nutt.) Haw. 



, Single or in clumps; tubercles with 5-8 brownish spines surrounded by 

 12-20 gray ones, often dark on the tips; flowers reddish or purplish with 

 fringed petals; berry ovoid, succulent. Dry sand hills, S. W. Man. and west- 

 ward to S. Alta." 



2. OPtTNTIA. Prickly Pear. 



Sepals and petals not united; stems in joints, flattened, with very 

 small, awl-shaped, deciduous leaves and clusters of bristles or spines 

 in the axils. 



