AMMIACEAE. 255 



1. HYDROCOTYLE L. Pennywort. 



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 pro- 

 liferous 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 w^anting 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. rannnculoides L. Floating or creeping in mud; leaves 

 round-reniform, 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 R. & P. 



Slender branching annuals with stellate pubescence, 

 opposite simple lobed leaves, scarious lacerate stipules, 

 and simple few-flowered umbels of white flowers on axil- 

 lary peduncles. Calyx-teeth rather prominent. Fruit 

 broadly ovate with narrow commissure and stellate 

 pubescence. Carpels turgid, becoming depressed on the 

 back, with neither ribs nor oil-tubes; the whole dorsal 

 region inflated, the seed-cavity being on the commissural 

 side of the carpel. Seed flattened dorsally, the face and 

 back plane or convex. 



1. B. septentrionalis C. & R. Stems weak, 0.5-6 dm. long, 

 dichotomously branching; leaves thin, cordate to reniform, 1.5-3 

 cm. broad, 3-5-lobed, the lobes entire or toothed, on long slender 

 petioles; umbels 1-4-flowered, on short peduncles; fruit about 2 mm. 

 long, sessile or nearly so. (B. lohata of recent authors, not of 

 R. & P.) 



Common throughout our range in the valleys and foothills, 

 usually growing on shaded slopes. 



