UMBELLIFBKAE (PAKSLEY FAMILY) 



611 



818. 8. trifoliata x 2%. 



broader ; sterile flowers on long slender pedicels ; 

 fruit ovoid or at maturity somewhat fusiform, tipped 

 with the conspicuous beak-like calyx. — Rich soil, 

 Kennebec Valley, Me. {Scriliner); and from the Ct. 

 Valley to Ont., Minn., and W. Va. Fig. 818. 



3. HYDROCdTYlE [Toum.] L. Water Pennywokt 



Calyx-teeth obsolete. Carpels with 2 of the ribs 

 enlarged and often foiming a thickened margin ; oil- 

 tubes none, but usually a conspicuous oil-bearing layer 

 beneath the epidermis. — Lciv mostly smooth marsh or 

 aquatic perennials, with slender creeping stems, round 

 shield-shaped or kidney-form leaves, and scale-like 

 stipules. Flowers small, white, in simple umbels or 

 clusters, which are either single or proliferous (one above 

 another), appearing all summer. (Name from vSap, 

 water, and Kori\ri, a flat cup, the peltate leaves of 

 several species being somewhat cup-shaped.) 



* Pericarp thin except at the broad corky dorsal and lateral ribs ; leaves round, 



peltate, crenate ; peduncles as long as the petioles, from creeping rootstocks. 

 + • Fruit notched at base and apex; intermediate ribs corky. 



1. H. umbellita L. Umbels many-flowered, simple (sometimes proliferous) 

 pedicels 4-12 mm. long ; fruit about 3 mm. broad, strongly notched, the dors; / 

 ribs prominent but obtuse. — Mass. to Fla. and Tex., chiefly on the coastij 

 plain ; also Mich, and Ind., and reported from Minn. 



2. H. Cdnbyi Coult. & Rose. Umbels 3-9-flowered, generally proliferous ; 

 pedicels very short, but distinct ; fruit 3-3.5 mm. broad; carpels broader and 

 more flattened than in the preceding, sharper-margined, the dorsal and lateral 

 ribs much more prominent ; seed-section much narrower. — N. J. to Md. 



1- -1- Fruit not notched; intermediate ribs not corky. 



3. H. verticillllta Thunb. Umbels few-flowered,- proliferous, forming an 

 interrupted spike ; pedicels very short or none ; fruit 3-4 mm. broad, subsessile; 

 dorsal and lateral ribs very prominent. — Mass. to Fla., Ark., and Tex. 



4. H. australis Coult. & Rose. Very like the preceding ; flowers pediceled. — 

 Dismal Swamp, Va. (Pollard according to Coult. & Rose), and south w. 



* * Pericarp uniformly corky-thickened and ribs all filiform ; leaves not peltate ; 



peduncles much shorter than the petioles. 



5. H. americllna L. Propagating by slender tuberiferous stolons ; stems 

 filiform, branching and creeping ; leaves thin, round-reniform, crenaie-lobed and 

 the lobjs crenulate, shining ; few-flowered umbels axillary and 

 almost sessile ; fruit less than 2 mm. broad ; intermediate ribs 

 prominent; no oil-bearing layer; seed-section broadly oval. — 

 Common. Fig. 819. 



6. H. ranunculoides L. f. Usually floating ; leaves thicker, 

 round-reniform, 3-7-cleft, the lobes crenate ; peduncles 2.5-7.5 

 cm. long, reflexed in fruit; capitate umbel 5-10-flowered ; fruit 

 2-3 mm. broad ; ribs rather obscure ; seed-section oblong. — 

 Muddy shores, e. Pa. to Fla., thence westw. (Trop. regions.) 



819. H. americana 

 x4. 



4. CENTlfeLLA L. 



Calyx-teeth obsolete. Petals white, imbricated in bud. Cai-pels 7-9-ribbed 

 and somewhat reticulated. — Creeping perennials with simple ovate leaves. 

 Umbels subtended by 2 conspicuous bracts. (Name of obscure origin.) 



1. C. asiitica (L.) Urban. Leaves repand-toothed, thickish; umbel 2-4- 

 flowered ; pedicels very short. (C repanda Small; Hydrocotyle asiatica L.) — 

 Md to Fla. (Tropics.) 



