288 UMBELLIFERAE. 



2. HYDROCOTYLE L. 

 Perennial herbs without erect stems, the peduncles and Leaves from creeping 

 stems or rootstocks. Leaves simple, round in outline, long-petioled. Flowers in 

 a small umbel, or disposed in 2 or more umbels which are proliferous one 

 above the other. Fruit flattened laterally, suborbicular, acutely margined and 

 with one or 2 ribs on each side. Oil-tubes none. (Greek hudor, water, and 

 COtule, a low vessel, the peltate leaves of some species being saucer-shaped.) 



Leaves nol peltate, S or 6-cleft: umbels simple 1. H. ranunculoides. 



Leaves peltate, slightly crenate; umbels proliferous. 



Fruit notched at base and apex 2. II. prolifera. 



Fruit not notched 3. //. cuneata. 



1. H. ranunculoides L. f. Water Pennywort. Stems floating or creep- 

 ing in mud, rooting at the nudes; herbage glabrous; leaves orbicular, 5 or 

 6-cleft, the lobes crenate, 1% i n - broad or less; petioles 3 to 5 in. long; 

 peduncles 1 to 2 in. long, reflexed in fruit; pedicels V2 line long; fruit ovoid, 

 1 line broad or broader; ribs obscure. 



Pools or muddy shores, often floating in rather deep water: San Francisco 

 to San Jose, south to Southern California, north to Washington and east 

 across the continent. 



2. H. prolifera Kell. Marsh Pennywort. Descending branches of the 

 rootstock tuberous-enlarged; umbels proliferous, one above the other in 3 or 4 

 whorls (each whorl 5 to 15-flowered) ; leaves orbicular-peltate, emarginate at 

 base, slightly crenate, l 1 /^ to 1% in. broad, petioles 10 to 13 in. long; 

 peduncles nearly as long; pedicels 1 to 3 lines long; mature fruit 1 line long 

 and slightly broader, slightly notched at base and apex. 



Marshes about San Francisco, thence to the lower Sacramento and lower 

 San Joaquin rivers. 



3. H. cuneata ('. & R. Habit of H. prolifera; fruit tapering to the pedicel 

 by a very distinct cuneate base. 



Suisun Marshes to Southern California, thence east to Texas. 



3. ERYNGIUM L. Button- Snakeeoot. 



Perennials with clustered fibrous roots, often dichotomously branching stems, 

 prickly involucres and often prickly leaves. Leaves opposite, or the upper some- 

 times alternate, simple, commonly oblanceolate and spinulose-serrate or 

 incised, or the radical, when growing in water, with fistulous petioles and the 

 blade more or less obsolete^. Flowers greenish white or bluish, condensed in 

 heads; heads terminal on the branches or 011 short peduncles in the forks; bracts 

 spinoso, conspicuous; bractlets usually Bpinose-tipped. Calyx-lobes persistent 



on the fruit. Fruit covered with whitish thin scales; ribs obsolete. Oil-tubes 



none. (Creek name used by I )ioscoridos.) 



1 leads greenish. 



Calyx-lobes in fruit longer than the stylos. 



Bracts and bractlets entire, callous-margined 1. F-. armaium. 



Bracts and bractlets Bpinulose, at least toward the base 2. H. vascyi. 



Calyx-lobes in fruit shorter than the >tyk-> 3. II. jepsonii. 



Heads very blue 4. E. articulation. 



1. E. armatumc. & B. ('oast Eryngo. Diffusely branching, the stems 



:: t., ."» or lo in. Long; Leaves broadly oblanceolate, incised or merely serrate. 



the teeth spiimse; bracts and bractlets very prominent, broadly lanceolate. 

 Strongly Bpinose-tipped, with an entire callous margin, sometimes scariotts- 



