Carrot Family 277 



Stylopodium flat or wanting. 

 Ribs thick and corky. 



Dorsal ribs filiform. 16. OENANTHE. 



All the ribs prominent and corky. 11. APIUM. 

 Ribs obscure or obsolete. 7. APIASTRUM. 



Oil-tubes more than 1 in the intervals. 



Stylopodium conic. 15. BERDLA. 



Stylopodium flat or wanting. 



Seed-face involute, inclosing a central cavity. 



10. DRUDEOPHYTUM. 



Seed face deeply sulcate. 9. DEWEYA. 



Seed-face plane. 14. SIUM. 



1. HYDROCOTYLE L. PENNEYWORT. 



Low herbaceous perennials growing in or near water, 

 with slender creeping stems, orbicular peltate or reni- 

 form leaves, and small white flowers in simple or prolif- 

 erous umbels, without involucres. Calyx-teeth minute 

 or obsolete. Fruit more or less orbicular, strongly flat- 

 tened laterally. Carpel with 5 primary ribs, broad or 

 filiform. Oil-tubes wanting or obscure. 



1. H. umbellata L. Descending branches of the rootstocks 

 with round tubers; leaves orbicular-peltate, crenate; peduncles 

 as long as the petioles; umbels many-flowered, simple, rarely 

 slightly proliferous; pedicels 4-12 mm. long; fruit with a thin 

 pericarp except at the broad thick corky dorsal and lateral ribs, 

 strongly notched, 2 mm. long, about 3 mm. broad, with dorsal 

 ribs prominent but obtuse. 



Frequent on borders of marshes and streams. Apparently more common 

 in the interior valleys. 



2. H. ranunculoides L. Floating or creeping in mud ; leaves 

 round-reniforin, 3-7-cleft, with crenate lobes; peduncles much 

 shorter than the petioles, reflexed in fruit ; umbel capitate, 5-10- 

 flowered; fruit corky, thickened throughout, ribs all filiform, 

 rather obscure. 



Common in pools or slow-running streams, especially toward the coast; 

 extending south at least as far as San Diego. 



2. BOWLESIA Pv. & P. 



Slender branching annuals with stellate pubescence, 

 opposite simple lobed leaves, scarious lacerate stipules, 



