588 LOASACEAE (LOASA FAMILY) 



LOASACEAE (LOASA FAMILY) 



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

 ent to a l-celled ovary with 2 or 3 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 3, more or less united 

 into 1 ; stigmas terminal, minute. Capsule 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. oligosp6rma Nutt. (STICK LEAF.) Much branched, 3-0 dm. high; 

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

 1.5-2 cm. broad, opening in sunshine ; petals 5, wedge-oblong, pointed ; stamens 

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

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



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

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

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

 dant ; seeds numerous. Rocky 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 l-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. Mamillaria. 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, crustaceous. 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 nipple, 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 ; flow- 

 ers red 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. missourinsis Sweet, var. caespitdsa (Engelm.) Wats. Smaller, stems 

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

 flowers yellow, 2.5-5 cm. broad; berry subglobose, scarlet; seeds few, pitted, 

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

 Tex., and westw. 



