140 DICOTYLEDONOUS PLANTS. 



with the petals. Styles 2, distinct ; stigmas simple. Fruit 

 consisting of two carpels, which are attached to a common axis 

 by their face (the commissure} from which they separate when 

 ripe; each carpel traversed by ribs or ridges, of which 5 are 

 primary, and 4 alternating with them, secondary. Seed soli- 

 tary, pendulous ; embryo minute, at the base of a horny albu- 

 men. 



Herbs with fistular furrowed stems. Leaves mostly com- 

 pound and sheathing at the base. Flowers in umbels. 



SUBORDER 1. ORTHOSPERMJE. 



Jllbumcn flat or flattish within. 



* Umbels simple or imperfect. 

 1. HYDROCOTYLE. Linn. 



Calyx with the tube subcompressed, and (he margin of the 

 limb obsolete. Petals ovate, entire, acute, with npex straight. 

 Fruit laterally compressed ; ribs 5, filiform, the middle and 

 lateral ones often obsolete. Umbel simple. Involucre few- 

 leaved. Pentandria. Digynia. 



1. H. intemtpta Muld. : stem filiform, creeping, rooting at the joints, 

 smooth ; leaves peltate, orbicular, doubly crenate ; flowers 58 in 

 axillary umbellate heads. H. vulgaris Mich. 



HAB. Wet places. Can. to Geor. Pursh. June Aug. 2J.. 

 Flowers minute, white, in small umbels or bunches, which are 

 much shorter than the petioles. Marsh Penny-wort. 



2. H. umbeJlata Linn. .* stem glabrous, rooting at the joints ; leaves 

 peltate-orbicular, doubly crenate ; emarginate at the base ; umbels 

 20 30-flowered j flowers distinct, pedicelled. 



HAB. Swamps. N. Y. to Geor. June Aug. It. Umbels on 

 peduncles longer than the leaves. Flowers white, minute. 



3. H. americana Linn. : root tuberous ; stem filiform, with long 

 creeping suckers ; leaves reniform, slightly 7-lobed, crenate ; umbels 

 few-flowered, axillary, nearly sessile. 



HAB. Moist places. Can. to Geor. June, July. 2f. Leaca 

 nearly orbicular, 9-nerved. Umbels 46 flowered, axillary. 

 Petals greenish- white. 



4. H. cymbalarifolia Muhl. : creeping, glabrous ; leaves reniform, 

 S-lobed, the intermediate one smaller, cordate, crenate ; umbels 

 few flowered, on peduncles ; flowers nearly sessile. H. ranunculoides 

 Linn.? Torn 



HAB. Penn. to Geor. June. If. Differs from the former in 

 having the leaves smaller, more coriaceous in their texture, more 



