Mentzelia. LOASACE^E. 235 



ORDER tXL. LOASACE.S3. 



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 Blumcnbachia of S. America (which twine and sting), 

 and 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 placentaj. 



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



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



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



1. MENTZELIA, Linn. 



Calyx-tube 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 placentae. 

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

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

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

 white and shining ; leaves alternate, mostly coarsely toothed or pinnatifid ; flowers 

 cymose or solitary, sessile 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 diy hillsides and valleys. 



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

 minutely fiexuous-striate longitudinally : petals 5, not large : filaments all 

 filiform : leaves petioled, serrately toothed. EUMEXTZELIA. 



M. ASPKRA, Linn. Annual, slender : leaves hastately 3-lobed, on slender petioles : flowers 

 axillary, sessile : petals about 3 lines long, but little exceeding the calyx-lobes : capsule narrowly 

 linear-clavate, an inch long. A tropical species reaching to Lower California (Xantux), Sonora 

 (Thurber), and Arizona (Rothrock), and to be looked for in Southeastern California. This is the 

 only species of true Menzelia that approaches the borders of the State. 



2. Seeds pendulous, few to rather many, small, in 1 to 3 rows, irregularly angled 

 or somewhat cubical, not winged, opaque, minutely tuberculate : flowers in ter- 

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

 form or the 5 outer more or less dilated : capsule linear : leaves sessile, flat, 

 simiately tootJied or pinnatifid : annuals. TRACHYPHYTUM, Torr. & Gray. 

 (Trachyphytum, Nutt.) 



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

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

 often lobed or toothed at base only : flowers mostly approximate near the ends of 

 the branches : calyx-lobes 1 i to 2 lines long, a little shorter than the spatulate or 

 obovate petals : filaments not dilated : capsule linear-clavate, 6 to 9 lines long : 

 seeds numerous, rather strongly tuberculate, irregularly angled with obtuse margins, 



