Genus 38. 



CARROT FAMILY. 



651 



38. CENTELLA L. Sp. PI. Ed. 2, 1393. 1763. 



Perennial herbs (some African species shrubby), ours with prostrate stems rooting and 

 sending up tufts of long-petioled leaves at the nodts, together with 1-3 long-rayed umbellets 

 of small white flowers, the true umbel sessile. Petiole-bases sheathing. Bracts of the invo- 

 lucels 2-4, mostly prominent. Calyx-teeth none. Disk flat, or slightly concave. Styles 

 filiform. Fruit somewhat flattened laterally, orbicular, reniform, or obcordate, rather promi- 

 nently ribbed, the ribs mostly anastomosing; oil-tubes none. [Latin, diminutive of centrum, 

 a prickle.] 



About 20 species, of wide distribution, most abundant in South Africa. The following is the 

 only one occurring in North America. Type species : Centella villosa L. 



I. Centella asiatica (L.) Urban. Ovate- 

 leaved Marsh-Pennywort. Fig. 3160. 



Hydrocotyle asiatica L. Sp. PI. 234. 1753. 

 Hydrocotyle refanda Pers. Syn. i : 302. 1805. 

 C. asiatica Urban in Mart. Fl. Bras. 11 : 287. 1879. 

 Centella repanda Small, Fl. SE. U. S. 859. 1903. 



Stem creeping, glabrous or somewhat pubescent, 

 i'-6' long. Petioles 3'-l2' long, sometimes pubes- 

 cent; blades ovate, rather thick, very obtuse and 

 rounded at the apex, broadly cordate at the base, 

 not peltate, I'-ii' long, 9"-i5" wide, repand-dentate ; 

 pedicels much shorter than the leaves, ¥-2' long; 

 umbels capitate, 2-4-flowered, subtended by 2 ovate 

 bracts; flowers nearly sessile; fruit 2"-2y' broad, 

 about li" high, prominently ribbed and reticulated 

 when mature. 



In wet grounds, Maryland to Florida, west to Texas. 

 Also in Bermuda, insular and continental tropical Amer- 

 ica, and Old World tropics. Jun«-Sept. 



39. SPERMOLEPIS Raf. Neog. 2. 1825. 

 [Leptocaulis Nutt. ; DC. Mem. Orab. 39. 1829.] 



Glabrous slender erect branching annuals, the branches often nearly filiform, with finely 

 dissected petioled leaves, the leaf-segments very narrowly linear. Flowers very small, white, 

 in compound unequal-rayed umbels. Involucre none ; involucels of a few small narrow 

 bracts, or none. Calyx-teeth obsolete. Fruit ovate, laterally flattened, tuberculate or bristly; 

 ribs prominent, or obsolete ; pericarp thick ; oil-tubes solitary in the intervals or also under 

 the ribs, 2 on the commissural side. Stylopodium short, conic. [Greek, scaly-seed, referring 

 to the rough fruit.] 



Four species, natives of the United States. Type species : Daucus divaricatus Walt. 

 Fruit tubercled. 



Umbel-rays divaricate. i. S. divaricatus. 



Umbel-rays ascending. . 2. S. patens. 



Fruit covered with hooked bristles. 3- S. echinatus. 



I. Spermolepis divaricatus (Walt.) 

 Britton. Rough-fruited Spermo- 

 lepis. Fig. 3161. 



Daucus divaricatus Walt. Fl. Car. 114. 1788. 



Leptocaulis divaricatus DC. Mem. Omb. 39. pi. 10, 

 1829. 



Apium divaricatum Wood, Bot. & Fl. 140. 1870. 



Spermolepis divaricatus Britton, Mem. Torr. Club 

 5: 244. 1894. 



Very slender and widely branching. Rays 

 of the umbels almost filiform, I'-iV long, 

 divaricate; flowers about i" broad; pedicels 

 filiform, 3"-6" long; fruit ovate, densely tuber- 

 culate, ¥ long, the ribs rather prominent. 



Nebraska to Texas, North Carolina and Florida. 

 Also in ballast at Philadelphia. April-May. 



