286 BRASSICACEAE 



nearly as long, the stem leaves smaller and sessile ; racemes densely flowered ; pedicels about 2 

 mm. long ; sepals 5-6 mm. long, stellate-tomentose ; petals much exceeding the sepals, white or 

 purplish ; pods notched both above and below, the thickened margin tomentose, the suborbicular 

 cells 6-8 mm. broad. 



Sandy soils in the deserts, Lower Sonoran Zone; Mohave and Colorado Deserts, southern California, and 

 in adjacent Nevada, Arizona, and Mexico. Type locality: California. March-May. Also called Spectacle Pod. 



Dithyrea californica var. maritima Davidson ex A. Gray, Syn. Fl. N. Amer. I 1 : 123. 1895. Leaves 

 thicker, distinctly fleshy, mostly suborbicular, shallowiy sinuate or entire, more densely canescent. Coast sand 

 dunes from San Luis Obispo to Los Angeles County, California. 



33. PHYSARIA A. Gray, Gen. 111. 1 : 162. 1848. 



Stellate-pubescent, cespitose perennials, with a taproot. Flowers racemose, perfect, 

 yellow. Petals spatulate. Stamens 6. Silicles dehiscent, inflated, didymous or obcom- 

 pressed; styles slender. Seeds several in each cell, not margined; cotyledons accumbent. 

 [Name Greek, meaning a bellows, from the resemblance of the inflated pod.] 



A genus of four species, natives of western North America. Type species, Physaria didymocarpa A. Gray. 



Pod much inflated at maturity, deeply cordate at base and apex. 1. P. didymocarpa. 

 Pod obcompressed, only slightly inflated, not cordate at base. 



Style 5-6 mm. long; pod rather narrowed at base. 2. P. Geyeri. 



Style 2-3 mm. long; pod rounded to slightly cordate at base. 3. P. oregona, 



1. Physaria didymocarpa (Hook.) A. Gray. Double Bladder-pod. Fig. 2049. 



Vesicaria didymocarpa Hook. Fl. Bor. Amer. 1 : 49. pi. 16. 1830. 

 Physaria didymocarpa A. Gray, Gen. 111. 1 : 162. 1848. 

 Physaria alpestris Suksdorf, W. Amer. Sci. 15: 58. 1906. 



Stems numerous, decumbent or erect, 3-15 cm. long. Basal leaves 1-8 cm. long, broadly ob- 



ovate, entire or repand-toothed, finely and densely stellate-pubescent, narrowed to a margined 



petiole; petals 8-14 mm. long, spatulate; style 5-7 mm. long; pod 7-15 mm. broad, deeply cordate 



at the base, the upper sinus acute, narrow. 



Sandy and rocky soils, Sonoran and Transition Zones; Saskatchewan and Alberta to eastern Oregon, 

 Nevada, Utah, and Colorado. Type locality: "Growing in deep sand upon the Rocky Mountains, between lat. 52° 

 and 57°." May-Aug. 



Physaria didymocarpa var. Newberryi (A. Gray) M. E. Jones, Proc. Calif. Acad. II. 5: 624. 1895. 



Style 3-4 mm. long. Usually at lower elevations than the species. Southern Utah, Nevada, and adjacent 

 California, east to New Mexico. 



2. Physaria Geyeri (Hook.) A. Gray. Geyer's Double Bladder-pod. Fig. 2050. 



Vesicaria Geyeri Hook. Lond. Journ. Bot. 6: 70. pi. 5. 1847. 

 Physaria Geyeri A. Gray, Gen. 111. 1 : 162. 1848. 



Plants whitish with a densely stellate tomentum, the stems ascending or decumbent, 5—15 

 cm. long. Basal leaves 2-5 cm. long, obovate to nearly orbicular, narrowed to a margined peti- 

 ole, repand-toothed or entire ; racemes rather dense ; petioles 8-12 mm. long, spatulate ; pods 

 broadly and shallowiy obcordate, narrowed toward the base, 12-16 mm. wide. 



Dry hillsides, especially in volcanic soils, Arid Transition Zone; eastern Washington to Montana and 

 Wyoming. Type locality: "Sunny sandy declivities or elevated volcanic places, Upper Spokane River," Wash- 

 ington. May— Aug. 



3. Physaria oregona S. Wats. Oregon Double Bladder-pod. Fig. 2051. 



Physaria oregona S. Wats. Proc. Amer. Acad. 17: 363. 1882. 



Plants canescent, the stellate pubescence not so white or dense as in the preceding species, 

 the stems ascending or decumbent, 10-15 cm. long. Basal leaves ovate, obtuse or rounded, 

 15-20 mm. long, narrowed to a slender petiole 3-5 cm. long ; pedicels mostly upwardly curved, 

 1 cm. long or more ; sepals ovate-lanceolate to oblong-lanceolate, 5 mm. long, well exceeding the 

 pale yellow petals ; pod 12-16 mm. broad, rounded or very shallowiy cordate at base ; valves 

 somewhat inflated, but narrowed dorsally to a keel; style about 1.5 mm. long. 



Gravelly soils, Arid Transition and Sonoran Zones; southeastern Washington and northeastern Oregon. 

 Type locality: "Gulches on Pine Creek, near Snake River, Union County, Oregon." May-Aug. 



34. LESQUERELLA S. Wats. Proc. Amer. Acad. 23: 249. 1888. 



Low annual or perennial herbs, with stellate pubescence, simple leaves, and racemose 

 mainly yellow flowers. Sepals oblong to elliptical, shorter than the entire petals. Stamens 

 6; anthers sagittate. Style slender; stigma entire or nearly so. Pod generally inflated, 

 subglobose or oblong ; valves nerveless, dehiscent ; septum suborbicular, nerved from the 

 apex nearly to the middle. Seeds several to many in each cell, flattened, marginless or 

 narrowly winged. [Name in honor of Leo Lesquereux, 1805-1889, Swiss and American 

 botanist.] 



A genus of about 35 species, natives of North America, and mainly the western United States. Type spe- 

 cies, Lesquerella occidentalis S. Wats. 



