29O CALIFORNIA ACADEMY OF SCIENCES. 



30. Gaura coccinea Nutt., Gen. i, 249. 



Type locality: " Declivities of bare, gravelly hills from 

 the Maha village to the Mandans." 



This species common on the plains around Denver was 

 collected along the sandy flats of the San Juan River 

 under the cottonwood trees. It is about 5 dm. in height, 

 branched from the base with stems simple up to the in- 

 florescence ; flowering stems elongating much beyond any 

 specimens heretofore seen, 15-18 cm. long; the whole 

 plant is almost glabrous. 



31. Mentzelia pterosperma n. sp. 



Annual, low, 10 to 20 cm. high, branching divaricately; 

 stem white, shreddy, covered with fine and coarse, barbed 

 hairs; lower leaves petioled, spatulate, often orbicular, 

 sinuate-dentate or rarely entire, 15 or 20 mm. long with- 

 out petiole, which is sometimes 10 mm. long; upper leaves 

 sessile, broad at base, 3 cm. long, 2 cm. wide, but not 

 uniform in shape or size; flowers on bracted peduncles 

 at the ends of the branches; divisions of calyx triangu- 

 lar-acuminate, half as long as the petals, almost glabrous 

 on the inner surface; petals lanceolate, 15 mm. long, 4 

 mm. wide, obtuse; outer stamens petaloid, anthers mi- 

 nutely scabrous; pods urnshaped, becoming chartaceous, 

 splitting irregularly, 15 mm. long, 10 mm. wide at the 

 top; seed 4 mm. in diameter, with a broad circular wing 

 equalling or surpassing in width the ovate body of the 

 seed, which is closely covered with minute white dots. 



The whole plant is hoary with stiff barbed pubescence; 

 the seeds in their shape and snowy whiteness remind me 

 of the hats worn by the Sisters of St. Vincent de Paul. 



Description drawn from specimens collected at Grand 

 Junction, Colorado; Moab, Utah, in 1892, and on Willow 

 Creek, July 14, 1895. Type in the Herbarium of the 

 California Academy of Sciences. 



