56S 



LOASACEAE. 



Vol. II. 



3. Nuttallia decapetala (Pursh) Greene. 

 Prairie-lily. Showy Mentzelia. Fig. 2980. 



Bartonia decapetala Pursh, in Bot. Mag. pi. 1487. 1812. 

 Bartonia ornata Pursh, Fl. Am. Sept. 327. 1814. 

 Mentzelia ornata T. & G. Fl. N. A. i : 534. 1840. 

 Mentzelia decapetala Urban & Gilg, in Engl. & Prantl, 



Nat. Pfl. Fam. 3 : Abt. 6a, III. 1894. 

 A^. decapetala Greene, Leaflets I ; 210. 1906. 



Roughish-pubescent, stout, seldom over 2° high. 

 Leaves oval, lanceolate or oblong, acute or acumi- 

 nate at the apex, sinuate-pinnatifid, 2'-6' long, the 

 upper sessile, the lower petioled ; flowers mostly soli- 

 tary and terminal, yellowish white, 3'-5' broad, open- 

 ing in the evening; petals about twice as long as 

 the lanceolate calyx-lobes ; calyx-tube usually bracted ; 

 filaments all filiform, very numerous (200-300) ; cap- 

 sule oblong, ii'-2' long, s"-6" thick; seeds numerous, 

 margined, not winged. 



Plains, Iowa to North Dakota, Saskatchewan, Mon- 

 tana, Nebraska and Texas. Gunebo-lily. June-Sept. 



Nuttallia laevicaiilis (Dougl.) Greene {.Mentzelia 

 laevicanlis (Dougl.) T. & G.] reported from Nebraska, 

 and admitted into our first edition, is not definitely 

 known within our area. 



Family 93. CACTACEAE Lindl. Nat. Syst. Ed. 2, 53. 1836. 



Cactus Family. 



Fleshy plants, with flattened terete ridged or tubercled, continuous or jointed 

 stems, leafless, or with small leaves (only the tropical genera, Pereskia and Percs- 

 kiopsis, with large flat leaves), generally abundantly spiny, the spines developed 

 from cushions of hairs or bristles (areolae). Flowers mostly solitary, sessile, ter- 

 minal or lateral,- perfect, regular, showy. Calyx-tube adnate to the ovary, its 

 limb many-lobed or with distinct sepals. Petals numerous, imbricated in several 

 rows, mostly distinct. Stamens numerous, inserted on the throat of the calyx. 

 Filaments filiform; anthers small. Ovary i-celled; ovules numerous, anatropous, 

 borne on several parietal placentae. Style terminal, elongated ; stigmas numerous. 

 Fruit a berry, mostly fleshy, sometimes nearly dry. Seeds smooth, or tubercled, 

 arillate, the testa usually crustaceous or bony ; endosperm little, or copious. 



About 40 genera and looo species, all natives of America, except some species of the epiphytic 

 genus Rhipsalis in tropical Asia and Africa. 



Stems subglobose, oval, ovoid or cylindric, tubercled. ribbed or angled ; no proper leaves. 

 Flowers borne on the tubercles or ribs, at or near the areolae. 



Flowers borne close to fully developed clusters of spines. i. Echinocereus. 



Flowers borne close to areolae, from which the spines subsequently develope 2. Pediocactus. 

 Flowers borne between the tubercles, distant from the areolae. 3. Coryphantha. 



Plants jointed, the joints flattened, or cylindric ; leaves present, terete and mostly early deciduous. 



4. Opuntia. 



I. ECHINOCEREUS Engelm. Wisliz. Tour North. Mex. 91. 1848. 



'Stems ovoid, cylindric or oval, ribbed, or tubercled, the ribs or rows of tubercles usually 

 straight, mostly vertical; leaves none. Spine-bearing areolae on the ribs or tubercles. Flowers 

 borne on the ribs or tubercles, at or near the areolae, close to fully developed clusters of 

 spines. Calyx-tube with spine-bearing areolae, or scaly, prolonged beyond the ovary. Fruit 

 spiny. [Greek, hedgehog-Ceretis.] 



About 65 species, natives of America. Besides the following, some 30 others occur in the 

 southwestern United States. Type species: Echinocereus viridifldrus Engelm. 



Flowers greenish, about i' broad ; fruit 5"-6" long. 

 Flowers rose-purple, 2'-3' broad; fruit 9"-io" long. 



1. E. viridifiorus. 



2. E. caespitosus. 



