Mentzelia. LOASACE.E. 2o5 



Order XL. LOASACE.2E. 



Herbaceous plants with either stinging or jointed and rough-barbed hairs, no 

 stipules, calyx-tube adnate to a 1-celled ovary, parietal placentae, or sometimes a 

 solitary suspended ovule, a single style, and anatropous seeds with a straight em- 

 bryo, mostly with little or no albumen. Stamens usually very numerous, rarely 

 few and definite, some of the outer occasionally petaloid or intermediate between 

 stamens and petals. Flowers perfect, often showy. 



An American order (with one African exception), of about 100 species, many in ornamental 

 cultivation, especially species of Loasa and Blwmcribachia of S. America (which twine ami sting), 

 ami of our first two genera. Of no other economical importance. 



1. Mentzelia. Stamens many, inserted below the petals. Style 3-cleft at the apex. Seeds 



few to many, on 3 parietal placenta?. 



2. Eucnide. Stamens many, adnate to the united bases of the petals and deciduous with them 



in a ring. Style 5-eleft. Seeds minute, very numerous, covering 5 expanded placentae. 



3. Petalonyx. Stamens 5. Style entire. Seed solitary. 



1. MENTZELIA, Linn. 



Calyx-tubo cylindrical to ovoid or turbinate ; the limb 5-lobed, persistent. Petals 



5 or 10. Stamens numerous, inserted below the petals on the throat of the calyx 



and not adnate to them : filaments free or in clusters opposite the petals, filiform, 



or the outer more or less dilated or sometimes petaloid and barren. Ovary truncate 



at the summit, 1-celled : style 3-cleft, the lobes often twisted : ovules pendulous or 



horizontal, few to many in one or two rows on the three linear parietal placenta'. 



Capsule short-oblong to cylindrical, few - many-seeded, opening by valves or usually 



irregularly at the truncate apex. Seeds fiat or angled. — Annual or biennial herbs, 



erect, more or less rough with rigid tenacious barbed hairs, the stems becoming 



white and sliming; leaves alternate, mostly coarsely toothed or pinnatilid ; flowers 



cymose or solitary, sessdo or nearly so, orange, golden yellow, yellowish, or white. 



About 30 species, nearly all confined to western North and South America ; forming several well- 

 marked subgenera. Confined, like the other genera, to dry hillsides and valleys. 



§ 1. Seeds feiv, pendulous, oblong (1 to 2 lines long), somewhat flattened, not winged, 

 minutely flexuous-slriate longitudinally: petals 5, not large: filaments all 

 filiform: leaves petioled, serrately toothed. — Eustentzelia. 



M, asff.ua, I, inn. Annual, slender : leaves hastately S-lobcd, on slender petioles : flowers 

 axillary, Bessilo : petals about 3 linos long, bu1 little exceeding the calyx-lobes : capsule narrow lv 

 lincar-clavate, an inch long, — A tropical pecies reaching to Lower California {Xantus), Sonora 

 ( Thurh r), and Arizona (JRothrock), and to ne looked for in Southeastern California, This is the 



only species of true .l/> u\, fin that approaches the borders of the Slate. 



§ 2. Seeds pendulous, few to rather many, small, in 1 to :! rows, irregularly ■< 



or s'lMi ir/rit enlticiil, nni /ringed, opaque, minutely tuberculate : flowers in ter- 

 minal cymes, mostly small: calyx-limb 5-parted: petals 5 : filaments all fili- 

 form or tlie 5 outer more or Ass dilated: capsuL linear: leaves sessile, flat, 

 sinuately toothed or pinnatifid: annuals. — Tkachyphytum, Torr. & Gray. 

 ( Trachyphytum, Xutt.) 



1. M. albicaulis, Dougl. Slender, .} to 1 foot high or more: leaves linear 

 lanceolate, pinnatifid with numerous narrow lobes, the upper leaves broader and 

 often lulled or toothed al base only: flowers mostly approximate mar the ends of 

 the branches : calyx-lobes l.l to 2 linos long, a little shorter than the spatulate or 

 obovate petals: lilaments not dilated: capsule lincar-clavate, 6 t>> '.• linos long: 

 seeds numerous, rather strongl) tuberculate, Irregularl) angled »i'li ol rgins, 



