Arabis. CRUCIFER^. *f% 



5. T. siricta (Graham) : erect, glabrous ; leaves lanceolate ; radical ones 

 pctioled, toothed ; cauline ones saijittatp, partly clasping, somewhat toothed ; 

 silifpies linear, elongated, and (like the flowers) strictly erect. Jlaok. — 

 Graham, in Edinb. 7iew phil.jour. ( 1829) /;. 7 ; Ilook. Ji. lior.-Am. l.p. 40. 



Oregon, Rocky Mountains. — (T) Habit of the preceding, but more slen- 

 der. Flowers white: petals obovate, emarginate' twice the length of the 

 calyx. Silique 2-3 inches long, rather broadly linear ; style short, much 

 narrower than the valves: stigma minute. Hook. 



6. T. patula (Graham): erect ; leaves lanceolate; radical ones petioled, 

 toothed or nearly entire, pubescent; cauline sagittate, partly clasping, gla- 

 brous (or sparingly pubescent) ; (lowers spreading ; siliques Hnear, elonga- 

 ted, much spreading. — Graham^ in Edinb. jour. I. c ; Hook. ! fl. Bor.-Am. 

 1. jp. 40. i 



Greenland and Hudson's Bay to the Rocky Mountains ! and Oregon. — @ 

 Stem 12-lS inches high, simple. Leaves an inch in length ; the radical and 

 lower cauline ones stellately hirsute. Flowers rather large, purplish or rose- 

 color. Siliques rather broadly linear, about 3 inches long, straight or a little 

 curved ; valves obtuse : stigma sessile. Seeds very distinctly 2-rowed, mar- 

 gined. 



7. T. retrofracta (Hook.): erect, canescently pubescent (or nearly gla- 

 brous) ; leaves lanceolate; radical ones petioled, toothed ; cauline sagittate, 

 partly chsping; flowers nodding; siliques linear, elongated, and (with the 

 pedicels) refracted. Hook. fl. Bor.-Am. 1. p. 41. Arabis retrofracta, Gra- 

 ham, in Edinb. jour. I. c. 



Hudson's Bay to the Rocky Mountains ; north to lat. 68°. — Flowers near- 

 ly white, or Avith a purplish tinge. — The (margined) seeds in a young state, 

 are in two rows, but in the mature fruit they are in a single series. Hook. 

 Graham. 



8. T. brachycarpa : glabrous and glaucous ; radical leaves spatulate, 

 toothed ; cauline ones linear-lanceolate, acute, sagittate and somewhat clasp- 

 ing ; siliques short, rather broadly linear; pedicels of the flowers pendulous, 

 of the fruit spreading or ascending. 



Fort Gratiot, Michigan, and Shore of Lake Superior, Dr. Pitcher! — @ 

 Stem 1-2 feet high, simple or sparingly branched above. Radical leaves pu- 

 bescent. Flowers rather large, pale purple ; the pedicels mostly bent doAvn- 

 ward. Silique about an inch long and nearly a line wide, straight or some- 

 what curved, usually spreading at right angles to the stem. Seeds mostly 

 abortive, in 2 distinct rows when young; the ripe and perfect ones nearly as 

 broad as the cell, winged on the margin. — The whole plant is sometimes of 

 a purple color. Nearly related to the preceding ; but distinguished by its 

 short siliques. 



9. T.? diffusa (Hook.): very glabrous and glaucous; stem diffusely 

 branched; radical leaves spatulate, nearly entire; cauline sagittate, slightly 

 toothed ; siliques linear, spreading, twice as long as the pedicels. Hook. ji. 

 Bor.-Am. 1. p. 41. 



Shores of the Arctic Sea. — Stems many from the same root, a span high. 

 Cauline leaves about an inch long, obtuse. Flowers small. Petals half the 

 length of the calyx, white. Silique scarcely an inch long. — Perhaps an Ara- 

 bis. Hook. 



6. ARABIS. Linn. : DC. syst. 2. p. 214. 



Silique linear, plane ; valves 1-nerved in the middle. Seeds in a single 

 series in each cell, oval or orbicular, compressed. — Flowers white, rarely rose- 

 color. 



