UMBEL L IFERA E. 67 1 



Oil-tubes numerous and close together 

 along; inner side of the pericarp ; ribs 

 filiform. 28. Berula. 



Introduced plant of dry ground. 



24. Pitnpinella. 

 2. Flowers yellow or purple. 

 Fruit dorsally flattened. 



Plants acaulescent ; leaves finely dissected. 44. Peucedanum. 



Plants leafy-stemmed. 



Leaves' pinnate ; segments ovate; fruit with thin lateral wings. 



46. Pastinaca. 

 Leaves pinnately compound ; fruit-wings thick and corky. 



41. Polytaenia. 

 Fruit not flattened ; ribs or some of them winged. 36. Thaspium. 



Fruit laterally flattened; leaves decompound (except in Zizia). 



Leaf-segments oval or ovate, entire. 23. Taenidia. 



Leaf-segments crenate, lobed or incised. 



Leaf-segments broad, crenate or dentate. 19. Zizia. 



Leaf-segments deeply incised. 



Plant native, western; ribs of the fruit filiform. 



14. Musineon. 

 Plant sparingly escaped from cultivation ; ribs prominent. 



18. Petroselinum. 

 Leaf-segments filiform ; fruit prominently ribbed. 



33. Foeniculum. 



1. HYDROCOTYLE L. (See Appendix.) 

 Perennial herbs, prostrate and commonly rooting at the joints, with palmately 

 lobed or veined, often peltate leaves, the bases of the petioles with 2 scale-like 

 stipules, and small white flowers in umbels opposite the leaves. Bracts of the 

 involucre few, or none. Calyx-teeth minute. Petals entire. Disk flat. Fruit lat- 

 erally compressed, orbicular or broader than high. Carpels with 5 primary ribs, 

 the lateral ones usually curved; no large oil-tubes, but an oil-bearing layer of tis- 

 sue beneath the epidermis. [Greek, water-cup.] About 75 species of wide dis- 

 tribution. Besides the following another occurs on the Pacific Coast. 



Leaves nearly orbicular, peltate. 



Umbels simple, rarely slightly proliferous; pedicels slender. 1. H. utnbellata. 



Umbels, at least some of them, proliferous; pedicels, or some of them, short. 



Fruit notched at each end. 2. H. Canbyi. 



Fruit not notched at either end. 3. H. verticillata. 

 Leaves nearly orbicular, cordate, or reniform, not peltate. 



Leaves 5-13-lobed ; umbels nearly sessile. 4. H. Americana. 



Leaves 3-7-cleft; umbels long-peduncled. 5. H. ranunculoides. 



i. Hydrocotyle umbellata L. Umbellate or Many-flowered Marsh- 

 pennywort. (I. F. f. 2703.) Glabrous; stem creeping, the subterranean branches 

 tuberiferous. Petioles slender, 2-15 cm. long; leaves sometimes cordate at the 

 base, 1-4 cm. wide, crenately 7-11-lobed, the lobes mostly crenulate; pedicels 

 slender, 4-12 mm. long; mature fruit notched at both ends, 2-3 mm. broad, not 

 quite as long; intermediate ribs corky-thickened; dorsal rib obtuse. In swamps 

 and low grounds, eastern Mass. to Fla. and the W. Indies, Minn., Tex. and Mex. 

 Also in S. Am. June-Sept. 



2. Hydrocotyle Canbyi C. & R. Canby's Marsh-pennywort. (I. F. 1. 

 2704.) Stems creeping, sometimes 3 dm. long, the subterranean branches tuberif- 

 erous. Leaves 1-4 cm. wide, with 7-1 1 shallow mostly crenulate lobes; peduncles 

 elongated; inflorescence mostly proliferous; verticils 3-10-flowered; pedicels 2-8 

 mm. long; fruit about 2 mm. long and 4 mm. broad, much flattened, the interme- 

 diate ribs corky-thickened, the dorsal one very obtuse. In moist ground, N. J. to 

 Md. June-Sept. 



3. Hydrocotyle verticillata Thunb. Whorled Marsh-pennywort. (I. F. 

 f. 2705.) Similar to the two preceding. Inflorescence proliferous, 2-5 cm. long; 

 verticils 2 -6-flowered; pedicels usually less than 1 mm. long; fruit about 2 mm. 

 long. 3-4 mm. broad, rounded or truncate at each end; intermediate ribs not corky- 

 thickened, the dorsal one acute. In moist soil, Mass. to Fla., west to southern 

 Cal., and in Central and S. Am. June-Sent. 



