52 CRUCIFER^E. PHYSARIA. 



PSILOXEMA. 



L. Donglasli Watson 1. c. 118. Canescent throughout with fine ap- 

 pressed pubescence : stems usually simple, from a simple caudex : leaves 

 ovate to oblanceolate or linear mostly entire : petals spatulate, 3-4 lines 

 long: pods obovate,'very obtuse, erect on spreading pedicels; cells 2- 

 ovuled. On the mountains of eastern Oregon and Washington. 



* * * Pods didymous with narrow nerveless partition. 



12 PHYSARIA Gray Gen. 111. i, 162. 



Low stellately canescent perennial herbs with mostly entire 

 leaves and yellow flowers. Petals spatulate to oblong, entire. 

 Filaments filiform. Anthers sagittate. Pods didymous : witli 

 a short narrow partition : cells inflated, nearly globular, mein- 

 branaceous, nerveless, several-seeded. Seeds not winged. Coty- 

 ledons accumbent. 



* Cells of the pods much inflated and longer than the partition. 



P. didymocarpa Gray 1. c. Very canescent, and lepidote with dense 

 white stellate pubescence : radical leaves petiolate, with roundish toothed 

 angled or entire blade, or oblanceolate ant! more or less sinuately-toothed 

 below: cauline leaves mostly entire, spatnlate; racemes dense : pedicels 

 becoming 6-7 lines long spreading or ascending : sepals lanceolate, shorter 

 than the rather pale yellow petals : pods strongly didymous, rather deeply 

 notched above entire or more or less cordate at base, becoming 6-8 lines 

 broad; valves subglobose, with no demarcation between the dorsal and 

 lateral surfaces ; walls papery. Eastern Oregon to Brit. Columbia and 

 Nevada. 



* * Cells more or less compressed and but little exceeding the 

 partition. 



P. Geyeri Gray 1. c. Whitish with dense stellate tomentum : radical 

 leaves with short, broadly ovate, entire, obtusely pointed blade narrowed 

 below to long channeled petioles; cauline leaves small, spatulate: racemes 

 rather dense, 1-2 inches long: pedicels spreading or curved, ascending, 3 

 lines long: pods small for the genus, broadly and shallowly obcordate, 

 narrowed towards the base ; cells 2)^-3 lines long at dehiscence ; partition 

 ovate much exceeded by the persistent style. Sandy soil and volcanic 

 ashes, upper Spokane valley, Washington. 



P. Oregona Watson Pr^c. Am. Acad. xvii, 363. Canescent: stems 

 several from the large woody root, 4-6 inches high : leaves oblanceolate- 

 spatulate, the lower few-toothed below ; the upper entire : pods obcom- 

 pressed 5-10 lines broad, round-reniform ; the narrowiy linear partition 3- 

 4 lines long ; the flattened obtusely rounded cells 3-4 seeded : style very 

 short. Gulches, Union county, Oregon. Cusick. 



* * * * Pods orbicular or nearly so. Filaments often dilated or 

 appendaged near the base. 



14 PSILONEMA C. A. Meyer in Ledeb. Fl. Alt. iii, 50. 



Low stellate-pubescent herbs with mostly simple leaves and 

 rather small flowers in slender racemes. Sepals equal. Petals 

 white or yellow, cuneate. Filaments unappendaged. Pods 

 oval or orbicular, compressed with convex nerveless valves, 2- 

 celled, with 2 seeds in each cell. Cotyledons accumbent. 



P. calycinum C. A. Meyer Bull. Acad. St. Pet. vii, 132. Stellate pub- 

 escent: stems branching from near the base, the branches mostly simple, 

 decumbant at base 6-1 2 inches long: leaves entire, linear-spatulate 6-12 



