20(19). Involucel lacking or inconspicuous; carpophore divided to the base; seed 

 face plane 6. Cryptotaenia 



20. Involucel conspicuous; bractlets entire; carpophore bifid or 2-cleft above the 



middle; seed face sulcate (21 ) 



21(20). Annuals; fruits 4-8 mm. long, obtuse at base 10. Chaerophylhun 



21. Perennials; fruits 10-20 mm. long, acute or caudate at base 7. Osmorhiza 



22(4). Fruit with uncinate prickles along the ribs 8. Caucalis 



22. Fruits glabrous or finely tuberculate, papillate or callous-toothed; petals with- 



out an inflexed apex (23) 



23(22). Fruit ribs filiform, rounded, subequally spaced; plants glabrous 



3. Spermolepsis 



23. Fruit ribs acute, the lateral of the two mericarps contiguous and appearing to 



form a single broad rib; plants roughened 5. Ammoselinum 



24(3). Lateral fruit ribs broadly winged, the dorsal very narrowly winged to 

 obsolete (25) 



24. Lateral ribs and one or more of the dorsal broadly winged or the oil tubes 



prominent but short (26) 



25(24). Plants annual; lateral fruit wings thick and corky; leaves entire or pal- 

 mately divided 21. Cynosciadium 



25. Plants perennial from fascicled tubers; lateral fruit wings thin, nerved dorsally 



at the inner margins, the fruit thus appearing 5-ribbed; leaves once- 

 pinnate or reduced to bladeless phyllodes 25. Oxypolis 



26(24). Leaves more or less dissected, without well-defined leaflets or with the 

 leaflets more or less cleft; ovaries glabrous 23. Conioselinum 



26. Leaves with more or less definite, entire or toothed leaflets or a few with 



irregular lobes; ovaries sparsely hispidulous or puberulent {Hera- 

 cleum lanaViim sometimes has glabrate ovaries) (27) 



27(26). Oil tubes extending only part way from the apex toward the base of the 

 fruit; herbage tomentose 26. Heracleum 



11. Oil tubes extending to the base of the fruit; herbage glabrous to pubescent 



24. Angelica 



28(1). Leaves reduced to hollow cylindric jointed petioles 19. Lilaeopsis 



28. Leaves with a definite blade, orbicular to round-reniform or ovate-cordate to 



oblong (29) 



29(28). Involucre of 2 conspicuous bracts; fruit with 3 primary and 2 reticulated 

 secondary dorsal ribs; petioles sheathing 2. Centella 



29. Involucre multibracteate, inconspicuous; fruit without secondary ribs; petioles 



not sheathing 1. Hydrocotyle 



1. Hydrocotyle L. Water-pennywort 



Plants low, glabrous or pubescent, herbaceous, perennial with slender creeping 

 stems or rootstocks, rooting at the nodes; leaves peltate or nonpeltate, entire or 

 parted to the base; inflorescence usually a simple umbel, sometimes proliferous or 

 an interrupted spike, the axillary peduncles obsolete to much longer than the leaves; 

 involucre inconspicuous, of numerous bracts; rays spreading to reflexed, sometimes 

 obsolete; flowers white, greenish or yellow, the calyx teeth minute or obsolete, the 

 stylopodium conspicuously conic to depressed; fruit ovoid to ellipsoid (broader 

 than long), strongly flattened laterally, the dorsal surface rounded or acute, the 

 dorsal ribs acute or obsolete, the slender lateral ribs conspicuous and acute or 

 rarely obsolete; oil-bearing cells conspicuous to obsolete, strengthening cells usually 

 surrounding the seed cavity, the seed face plane to concave. 



A genus of about 100 species, chiefly of the tropics and the Southern Temperate 

 Zone. 



The seeds and occasionally the foliage are eaten by wildfowl; H. umbellata is 

 considered to be especially desirable as duck food. 



1214 



