fl* 1f >.and* ^ thepediceJs, glabrous. DC. syst. 2.p. 346; Deless. ic. 2. t.
4b. ƒ. A ; Hook.Jl. Bor-Am. 1. p. 53.
Rocky Mountains lat. 52°-57°.-Flowers white. Silkies 6 lines long and
scarcely one line wide. DC,
16. D. crassifolia (Graham): scape naked or with a single lea f; calvx
and pedicels glabrous ; leaves hnear-spatulate, somewhat fleshy, ciliate with
simple hairs; petals a little exceeding the calyx; retuse; silicles ovate-elliptical,
glabrous. Graham, in Edinb.phil.jour. 1829. p. 182; Hook.' H Bor -
Am. 1. p. 54. J
a. petals white. Hook. t e .
0- petals pale yellow. Hook. l. c.
i °^ ,^ e Rocky Mountains, lat 52°-57°, Drummond ! and about
7 5 yuttd ll.-—]Scapes 1-2 inches high: flowers small. Silicles glabrous.
Book. Leaves lanceolate-lmear, entire or somewhat serrate. Nutt.
* * Perennial: stems leafy.
17. D.7 lavigata (Cham. & Schlecht.): stem leafy, simple, glabrous,
strict'; radical and inferior cauline leaves petioled, ovate, attenuate at the
base, somewhat fleshy, the margin obscurely ciliate; silicles oblong-lanceolate
glabrous, 4-6 times as long as the pedicels. Cham, f Schlecht. in Linncka,
l . p . 25; Hook.Jl. Bor.-Am. 1. p. 54.
Island of St. Lawrence, Chamisso.—Root thick, descending. Radical
leaves tew, (not in a rosulate cluster) with the petiole 1J-2 inches long.—
Stems several, 3-4 inches high in flower, elongated in fruit. Flowers white.
Silicles 7-8 lines long, and 3-4ths of a line broad : style very short. Seeds
not seen. Cham. $ Schlecht.—Hooker has placed this in his secdnd section,
including the annual and biennial species; but the authors above quoted state
it to be perennial. '
18. ^0. ramosissima (Desv.): puberulent; stems numerous ; leaves linear-
lanceolate, remotely and sharply laciniate-toothed; racemes corymbosely
paniculate; silicles lanceolate, attenuate at each end, pubescent; style one-
fourth the length of the silicle.—Desv. jour. bot. 3. p. 168; DC. syst 2 p
355; Gray ! in ann. lyc. New- York, 3. p. 224. D. arabisans, Pursh! fl. 2. p.
434. (not of Michx.) D. dentata, Hook, dp Arn.! in jour. bot. 1. p. 192
(without descr.); Hook.! ic. 1. 1. 31. Alyssum dentatum, Nutt. ! gen. 2.
On rocks, Harper’s Ferry, Virginia ! and Cliffs of Kentucky River, Short!
Apni-May.—-Rhizoma creeping, branching and throwing up tufts of stems,
which are about a span high. Pubescence simple and stellate (mostly with
4 rays). Radical leaves rosulate, crowded, with a long cuneiform base; cauline
ones sessile, almost pectinately toothed; the teeth 2-3 on each’ side.
Racemes forming a large spreading panicle : flowers white. Pedicels erect-
spreading, about as long as the somewhat contorted silicle. Seeds 4-7 in each
cell.—A very distinct species, with much the habit of D. arabisans.
19. D. arabisans (Michx.): slightly and stellately pubescent; stem leafy
simple or branching from the base, leaves acutely toothed, radical ones cune-
ate-lanceolate, the cauline oblong; silicles glabrous, lanceolate-oblong, acuminate
with a very short but distinct style; petals (white) about twice as long
as the sepals.—Michx. ! fl. 2.p. 28; DC. prodr. l.p . 170; Hook. Jl. Bor.-
Am. l. p. 55. D. mcana 0. glabnuscula, Gray ! in ann. lyc. New-York 3
p. 223.
0. leaves nearly entire, radical ones rather obtuse; style almost wanting —
D. Longii.herb. Schwein.!; N u tt.! mss.
Rocks, Lake Champlain, Michaux ! and on the borders of small lakes in
the northern part of the State of New Y ork! 0. Fort Gratiot, and N. shore
of Lake Superior, Dr. Pitcher /—Stems many from a single root, 6-8 inches
high. Radical leaves numerous, forming a rosulate tuft, 1-14 inch long,
acute, much attenuated at the base, furnished with 2 (rarely more) very acute
spreading teeth on each side, sometimes entire; cauline leaves somewhat
clasping. Flowers in a short close nearly simple raceme. Petals broadly
ovate. Silicle half an inch long, contorted; cells about 10-seeded; lower
pedicels nearly as long as the silicle ; upper ones shorter, often cohering by
pairs nearly or quite to the summit.—Nearly related to D. mcana, and also to
D. hirta. We have seen in the herbarium of the Academy at Philadelphia,
specimens of the var. 0.; but the locality is not recorded.
*** A'n/rmal or biennial: stems leafy.
20. D. incana (Linn.) : stem leafy, simple or branching, clothed with a
velvety stellate pubescence; leaves ovate, toothed; silicles oblong, glabrous
or pubescent, contorted or straight.
a. cauline leaves ovate, acutely toothed; silicles mostly contorted, glabrous
; style very short.—D. incana, Fl. Dan. t. 130 ; Pursh, ft'. 2. p. 434;
Hook.Jl. Bor.-Am. l.p . 54. D. contorta, Ehrh.; DC.prodr. l.p . 170.
0. confusa: leaves sparingly toothed; silicles pubescent.—D. incana, var.
Linn. D. confusa, E hrh.; DC. prodr. 1. c. ; Hook.! ft. Bor.-Am. 1. p. 54.
y. borealis: somewhat hirsute; stem-leaves few, ovate ; radical ones oblong,
attenuate at the base, entire; silicles . . . (ovaries ovate)—D. borealis,
DC. syst. 2.p. 342. (fide Hook.)
a. Labrador. 0. Arctic America and the Rocky Mountains, y. Islands of
St. Lawrence and Unalaschka.—@ and If'? Stems 6-10 inches high, usually
several from one root. Raceme somewhat compound. Hook.
21. D. glabella (Pursh) : slightly and somewhat stellately pubescent; radical
leaves oblong-spatulate ; cauline ones 2-4, ovate, toothed or entire; petals
(white) more than twice as long as the very smooth calyx; silicles. . . Hook.
—Pursh, fl. 2,p. 434? ; Richards, app. Frankl. jour. ed. 2. p. 27 ; Hook,
fl. Bor.-Am. 1. p. 54. ■
Margins of alpine rivulets in the Rocky Mountains, between lat. 52°-57°.
Hudson’s Bay, Pursh.—Habit of D. crassifolia, but 3—4 tunes the size, and
the flowers as large as any of the genus. Silicles not seen. Hook.
22. D. Unalaschkiana (D C .): stem leafy, simple, pubescent; leaves
ovate-oblong, entire, pubescent; silicles oblong, minutely hirsute. DC. syst.
2.p. 380; Hook.fl. Bor.-Am. l.p . 55.
Unalaschka.—Petals (white) twice as long as the calyx; lamina obovate,
emarginate. DC.
23. D. aurea (Vahl) : pubescent; stem erect, leafy ; leaves lanceolate or
ovate-lanceolate, acute, entire or toothed; corymbs terminal and axillary;
silicles oblong-lanceolate, pubescent, 3 times as long as the pedicels ; petals
(yellow) emarginate; style rather short. Hook.—Fl. Dan. t. 1460; DC.
prodr. 1. p. 170; Hook. Jl. Bor.-Am. % p. 55, f in bot. mag. t. 2934.
Rocky Mountains.—Flowers sometimes white. Hook.
24. D. lutea (Gilib.): pubescent; stem branching, leafy; leaves oval;
cauline ones lanceolate, toothed; silicles oblong-elliptical, glabrous, about 30-
seeded, one-third the length of the pedicels. Hook..—DC. prodr. l.p . 171;
Hook. fl. Bor.-Am. l.p . 55. t jj l
0. longipes (DC.) ; pedicels 3-4 times the length of the silicles.—Hook.
1. c.—D. gracilis, Graham, in Edinb. phil. jour. 1828. p. 172.
Arctic and Subarctic America ! Grassy moist places at the junction of the
Wahlamet and the Oregon, Nuttall /—Stem 6-15 inches high, very slender,