AMMIACEAE 977 
4. TREPOCARPUS Nutt. Annual herbs. Leaf-blades pinnately decom- 
pound.  Umbels compound. Involucre usually present. Sepals unequal. 
Petals white, broad. Fruit elongate: ear- 
pels with 4 secondary ribs, the primary 
ribs wanting: oiltubes solitary under the 
secondary ribs.—One species. 
t 
smesse | 
Ae D 
Aethusae Nutt. ESO em En dm. tall, 
ECHHIEEEECERH OYP 
4444 
ee Lt 
attt LIT 
te 
— 
t 
equal to them in length, the d short- 
gm r, n 
petioled, the se — narrowly lin en 
or incised: umbe z commonly long- N 
peduncled: rays 2- 5, becoming 1-2 cm. long: E 
E ers den ew in each. etc fruit ML | A 2 
8-10 long, sharply ribbed.—Dry soil, a C 3 
Coastal "Plain and adj. provinces, Ala. p 5 
Tex., Okla., and Ark sum. 
25. PTILIMNIUM Raf. Annual, faintly-scented, slender herbs. Leaf- 
blades jos -pinnately or -ternately divided, the ultimate segments entire or 
nearly so. Umbels compound.  Involueres and involucels of several very 
slender, entire or pinnate bracts, and bractlets. Sepals small, broad or nar- 
row. Petals white, each with a broad body and a short entire inflexed apex. 
Stylopodium nM or elongate. Fruit short, as wide as long or nearly 
so: carpels with prominent separated dorsal and intermediate ribs and thick 
corky lateral n oil-tubes small between each rib. Seed terete-angled, the 
inner face convex. or gowns are the only EDONA species—Mock BISHOP’S- 
Sepals deltoid, often broadly s | . 1. P. capillaceum. 
Sepals subulate to narrowly Pm eolat 
Styles long, much longer tah "o E stylopodium 
ovoid, together with the styles over mm. long: leaf- 
blades rather long-petioled. 2. P. costatum. 
Styles short, about as long as the stylopodium : ena 
depressed, together with the styles, less than 1 mm. lon 
leaf-blades short-petioled. 3. P. Nuttallü. 
1. PR. peers uuu x.) Raf. Plant 2-8 dm. tall: leaf-segments relatively 
few and lax: um ys few-several, less than 2.5 em. long at maturity: braets 
lobed: zi her pos mm. long, ac acute. 
—Wet s marshes, swamps, and ditches, 
various sa e) Fla. to Tex. Kans., and 
ass. 
2. P. costatum (Ell) C. & R. Plant 8-16 
dm. tall: leaf-se segments auld linear, 
numerous, en not crowded: umbel-rays 
stout, over 3 e at maturity: bracts 
entire or lobed: ` petals fully ] mm. long: 
fruit ovoid, mm. long or Los ‘longer, 
not MEC E at the apex ee 
Coastal Plain, Ga. to N. C.—Sum.—fall. 
3. P. Nuttallii (DC.) Britton. Plant 3-7 
dm. tall: leaf-segments almost eapillary, 
b 
