588 LOASACEAE (lOASA FAMILY) 



LOASACEAE (Loasa Family) 



Herbs, with a rough or stinging piihesrence, no stipules, the calyx-tube adher- 

 ent to a 1-celled ovary with 2 or 8 parietal placentae ; — represented here only by 

 the genus 



1. MENTZELIA [Plumier] L. 



Calyx-tube cylindrical or club-shaped ; the limb 5-parted, persistent. Petals 

 5 or 10, regular, spreading, flat, convolute in the bud, deciduous. Stamens in- 

 serted with the petals on the throat of the calyx. Styles 8, more or less united 

 into 1 ; stigmas terndnal, minute. Cap.sule at length dry and opening at the 

 summit. Seeds flat, anatropous. — Stems erect. Leaves alternate, very adhe- 

 sive by the barbed pubescence. (Dedicated to C. Mentzel, an early German 

 botanist.) 



1. M. oligosperma Nutt. (Stick Leaf.) Much branched, 3-9 dm. high; 

 leaves ovate and oblong, cut-toothed or angled, often petioled ; Jloioers yellow, 

 Lo-2 cm. broad, opening in sunshine ; pet(ds 5, wedge-oblong, pointed ; stamens 

 20 or more ; capsule small, aijout 9-seeded. — Limestone hills and banks, 111. to 

 Kan. and Col., s. to Tex. May-Aug. 



2. M. decapetala (Pursh) Urban & Gilg. Larger in all its parts ; leaves 

 elongate-lanceolate, sharply and coarsely dentate ; floivers white or pale yellow, 

 7-12 cm. broad, opening in the evening ; petals 10, lanceolate ; stamens abun- 

 dant ; seeds numerous. — Kocky hillsides and dry prairies, n. w la. to Sask., 

 Tex. , and westw. July-Sept. 



CACTACEAE (Cactus Family) 



Fleshy and thickened mostly leafless plants, globular or columnar and^ many- 

 angled, or flattened and jointed, usually with prickles. Flowers solitary, sessile ; 

 the sepals and petals numerous, imbricated in several rows, the bases adherent 

 to the 1-celled ovary. Stamens numerous, inserted on the inside of the tube or 

 cup formed by the union of the sepals and petals. Style 1 ; stigmas numerous. 



1. Mamlllaria. Globose or ovoid plants, covered with spine-bearing tubercles. Flowers from 



between the tubercles. Ovary naked ; berry succulent. 



2. Opuntia. Branching or jointed plants ; the joints flattened or cylindrical. 



1. MAMILLARIA Haw. 



Flowers about as long as wide, the tube campanulate or funnel-shaped. 

 Ovary often hidden between the bases of the tubercles, naked, the succulent 

 berry exserted. Seeds yellowish-brown to black, crnstaceous. — Globose or 

 ovoid plants, covered with spine-bearing cylindrical, ovoid, or conical tubercles, 

 the flowers from distinct woolly or bristly areoles at their base. (Name from 

 mamilla, a nijiple, referring to the tubercles.) 



1. M. vivipara (Nutt.) Haw. Single or tufted, 2,5-12 cm. high, the almost 

 terete tubercles bearing bundles of 5-8 reddish-brown spines (2 cm. long or less) 

 surrounded by 15-20 grayish ones in a single series, all straight and rigid ; flovj- 

 erx rfd or purple, with fringed sepals and lance-.subulate petals ; berries ovoid, 

 green; seeds pitted, light brown. (Cactus Nutt.) — Granite ledges, w. Minn. 

 (Moyer), and on prairies and dry plains to Alb. and Cal. 



2. M. missouriensis Sweet, var. caespit5sa (Kngelm.) Wats. vSmaller, stems 

 globose, clu.stered, the tubercles with fewer (10-20) weaker ash-colored spines; 

 flowers yellov), 2.5-5 cm. broad ; beri'y subglobo.se, scarlet; seeds few, pitted, 

 black. {Cactus missouriensis, var. similis Coult.) — Dry prairies, e. Kan. to 

 'I'ex., and westw. 



