pressed, but not contracted at the commissure. Intervals broad and a little
convex, dark green. Seed free, but without any cavity between it and the
pericarp.
47. MUSENIUM. Nutt. mss.
“ Margin of the calyx 5-toothed; thé teeth persistent. Petals obovate; the
point indexed. Styles slender, reflexed, rather long. Fruit ovate ‘or ovate-
oblong, laterally compressed. Carpels more or less minutely scabrous, with
5 filiform acute slightly prominent ribs. Intervals with 2-3 vittae. Commissure
with 4 vittse. Carpophore 2-cleft. Seed with the sides moderately
incurved. Perennial dwarf rather foetid resiniferous (North American) herbs,
with fusiform roots, and a short caudex, or branching dichotomously from the
base. Leaves 2-3-pinnatifid. Involucre .none. Involucels unilateral, of a
few rather rigid narrow leaflets. Flowers yellow or white.” Nutt.
§ 1. Stem dichotomous: flowers yellow.
1. M . divaricatum {Nutt.! mss.): decumbent; stem short, dichotomously
branching from the base ; leaves bipinnatifid ; divisions confluent with the
winged rachis ; segments short, rather acutely toothed ; fruit somewhat glabrous.—
Seseli divaricatum, Pursh, fl. 2. p . 732? ; Nutt. gen.. 1. p . 194 ;
P C . prodr. 4. p . 146.
0. Hookeri : rachis narrow ; fruit scabrous, with elevated points.—M.
Hookeri, N u tt.! mss. Seseli divaricatum, Hook. ! fl. Bor.-Am. 1. p . 264 ;
Sims, hot. mag. t, 1742. (ëx Hook.)
Naked and arid hills and plains of the Upper Missouri, N u tta ll! 0. Plains
of the Upper Platte, near the Rocky Mountains, Nuttall! On the Saskatch-
awan, Prummond! Pouglas. May.—Plant about a span long. Leaves all,
except the radical ones, opposite, glabrous and shining: petiole and rachis
distinctly winged: lamina with an ovate outline ; primary and secondary
divisions 3-4 pairs; the segments about one-third of an inch long,. 3-4-
toothed. PedunCtés 4-5 inches long, scabrous, naked, rigid, stout. Umbels
10-20-rayed ; the rays (in fruit) about half an inch long. Fruit 2 lines long,
oblong-ovate : pericarp thin : vittse filled with' a strong terebinthine oil.—■
The plant exudes small drops of resin spontaneously.
2. M . trachyspermum (Nutt, mss.) : “ decumbent; leaves bipinnatifid;
segments pinnatifid, rather obtuse, the lobes often 2-3-cleft and very short;
rachis wide; fruit short, oval, pulverulently scabrous.”
“ With the preceding, to which it is nearly allied, but differs in the fruit;
which is only half as large, the breadth nearly equalling the length. Invo-
lucel about 8-leaved, short.” Nuttall.
3. M. angustifolium \ Nutt.! mss.); “ decumbent, with several stems from
one root; leaves bipinnatifid, with a wide rachis ; the uppermost almost simply
pinnatifid; segments lanceolate, entire, or acutely denticulate; fruit elliptical,
slightly scabrous.
“ Plains of the Upper Platte, within the Rocky Mountains.—Differs from
the preceding species in the longer leaves, and distant, narrow, less divided
segments.” Nuttall.
§ 2. Stemless: flowers white.—D aucophyllum, Nutt. mss.
4. M. tenuifolium (Nutt.! mss.): erect and somewhat caespitose; leaves
all radical, tripinnately divided; the segments narrowly linear, acute ; fruit
nearly glabrous.
Rocky Mountains, N u tta ll!—Plant about a span high, of a glaucous hue,
growing in tufts. Leaves divided like those of the Carrot, but much smaller.
Peduncle much longer than the leaves, with a small crowded umbel of 12—
20 rays. Involucel 7-9-parted; the segments lanceolate. Fruit (immature)
oblong-elliptical; the ribs nearly obsolete: intervals with 2-3 conspicuous
vittae, which are filled with a more aromatic oil than in the species of the
preceding section.
Series 3. Seed with the base and the apex curved inwards, or sac-
cately concave. (Subord. Ccelospekjue, DC .)
T ribe XIII. CORIANDREiE. Koch; P C .
Fruit globose ; or the carpels subglobose and didymous ; primary
ribs o f each carpel 5, depressed and flexuous, or nearly obsolete;
the secondary ones 4, more prominent: all wingless.—Umbels
compound.
48. ATREMA. P C . mem. Urrib. p . 71, t. 18, Sf prodr. 4. p. 250.
# Calyx-teeth 5, acute, small, persistent. Petals obovate, deeply emar-
ginate. Fruit didymous. Carpels subglobose, ventricose, with 4 somewhat
prominent ribs. Vittae none. Commissure closed. Seed conspicuously
involute at the base and summit.—An annual herb, with angular
stems; the angles, as well as the rays of the umbels and margin of the
leaves, muricate-scabrous. Leaves many-cleft, with linear segments.
Umbel and umbellets 5-8-rayed. Involucre and involucels of several
3-eleft or entire leaflets. Flowers white. Fruit with but little taste, from
the absence of vittae.
A . Americana (D C .! 1. c.)
Prairies of Arkansas, N u tta ll! P r . Leavenworth! P r . H a le ! Texas,
Prummond !—Plant 12-18 inches high, every part, particularly the angles
of the stem near each leaf and below the umbel, roughened with minute
callous points. - Segments of the leaves almost capillary. Rays of the
umbel about an inch long. Involucellate leaves 2-4, (“ entire,” P C ., but
trifid in his figure!) divided to the middle; the segments subulate. Fruit
resembling that of Coriander (Coriandrum sativum), but rather smaller:
the primary ribs slightly prominent and somewhat flexuous.
49. APIASTRUM. Nutt. mss.
Margin of the calyx nearly obsolete. Petals somewhat orbicular, entire,
concave (not inflexed at the apex). Styles very short. Stylopodium minute.
Fruit didymous, much contracted at the commissure. Carpels ovate-
globose, with 5 slightly elevated rugulose ribs, and single vittae in the in