UMfcELLIFERAE (PARSLEY 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. (Scribner') ; and from the Ct. 

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



3. HYDROC6TYLE [Tourn.] L. WATER PENNYWORT 



Calyx-teeth obsolete. Carpels with 2 of the ribs 

 enlarged and often forming a thickened margin ; oil- 

 tubes none, but usually a conspicuous oil-bearing layer 

 beneath the epidermis. Low 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 vdwp, 

 water, and KOTI/XTJ, 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. 

 t- Fruit notched at base and apex; intermediate ribs corky. 



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

 pedicels 4-12 mm. louy ; fruit about 3 mm. broad, strongly notched, the dorsal 

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

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



2. H. Canbyi Coult. & Rose. Umbels 3-$-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. 



-<- +- Fruit not notched ; intermediate ribs not corky. 



3. H. verticillata 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 southw. 



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



peduncles much shorter than the petioles. 



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

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

 the lobes 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. rammculoides 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. 819. H. 

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



americana 

 x4. 



4. CENTELLA L. 



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

 and somewhat reticulated. Creeping perennials with simple ovate leaves. 

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



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

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

 Md. to Fla. (Tropics.) 



