608 UMBELLIFERiE. Leptocaulis. 



foot high (/?. 4-5 feet, Ell.). Stem often much branched. Leaves ternately 

 dissected, with numerous spreading segments. Involucral leaves sometimes 

 2-3-pinnatifid. Rays of the umliel seldom more tliau 8, an inch or 

 more long. Umbellets shorter than the involucel. Fruit ovate, rather acute, 

 about a line and a half in length. — We have not seen the Ammi costatum of 

 Elliott. 



2. D. Nuttallii (DC): erect; umbels about 20-rayed ; leaflets of the 

 involucre mostly entire ; fruit orbicular. — DC. I. c. t. 9, Sf prodr. 4. p. 107. 



Wet prairies, Kentucky [Short!) to Louisiana! and Tampa Bay, East 

 Florida! west to Texas ! — Plant 2-6 feet high, branching above. Divisions 

 of the leaves somewhat verticillate. Involucre commonly less than lialf the 

 length of the rays ; the leaflets sometimes 3-cleft. Fruit smaller than in the 

 preceding species, rather broader than long. 



9. LEPTOCAULIS. Nutt.in DC.mem. Umb.p.39,t.-iO,S^'prodr. A. p. 107. 



Margin of the calyx obsolete. Petals elliptical, entire. Fruit crowned 

 with the styles, laterally compressed, ovate. Carpels with 5 slightly promi- 

 nent ribs; the lateral ribs marginal. Intervals with single vittse. Commis- 

 sure with 2 vittse. Carpophore slightly 2-cleft at the summit. Seed convex 

 on the back, flat on the face. — Erect very slender (North American) glabrous 

 herbs, with terete stems. Leaves many-cleft ; the segments linear. Um- 

 bels pedunculate, opposite the leaves and terminal, with few rays. Invo- 

 lucre none. Rays of the umbellets few and unequal, with a short few- 

 leaved involucel. Flowers small, white. 



* Fruit neither scabrous nor echinate. 



1. L. inermis (Nutt.) : fruit unarmed, somewhat rugulose. — Nutt. .' in 

 DC. mem. I. c. t. 10,/. 2, S^- prodr. 4. p. 107. 



Prairies of Arkansas, Nuttall! — Stem about a span high. Involucre 

 wanting : involucels of 4-6 leaflets, as long as the partial rays. Rays of 

 the umbel unequal, the longest scarcely half an inch in lengtli, with 1 or 2 

 short-pedicellate flowers in the centre. Rays of the umbellets 2-3 lines 

 long. Fruit rather smaller than a mustard seed, slightly ribbed, with minute 

 intermediate rugse. 



* * Fruit muricate or echinate. 



7"^' 2. L. diffusus (Nutt.) : fruit muricated with very short somewhat appress- 

 ed scales ; umbels and umbellets 3-4-rayed ; pedicels filiform, two-thirds as 

 long as the rays of the umbel. — -Nutt. ! in DC prodr. 4. p. 107. 



Prairies of Arkansas, Nuttall ! Texas, Drummond ! — Plant 8-15 inches high,- 

 very slender and divaricately branched. Rays of the umbel an inch or more 

 in length. Fruit roughened with minute tubercles, which terminate in short 

 scales or bristles. 



',^3. L. divaricatus (DC.) : fruit muricated with very short somewhat ap- 

 pressed scales ; umbels 3-6-rayed ; pedicels filiform, half the length of the 

 rays of the umbel. — DC. mem. I. c. t. 10./. A, Sf prodr. 4. p. 107. Daucus 

 divaricatus, Walt. Car. p. 114. Sison pusillum, Michx. fl. 1. p. 168 ; Ell. 

 sk. 1. p. 356. Ammi divaricatum & Ligusticum pusillum, Pers. syn. 1. 

 p. 308 c!^ 315. ^thusa divaricata, Nutt. ! gen. 1. p. 190. 



Dry sandy soils, South Carolina ! and Georgia ! March- April. — Stem 1-2- 



