UMBELLIFER^E. ( PARSLEY FAMILY.) 199 



jtices or intervals between them are commonly lodged the oil-tubes (yitt<z), 

 which are longitudinal canals in the substance of the fruit, containing 

 aromatic oil. (These are best seen in slices made across the fruit.) Seed 

 suspended from the summit of the cell, anatropous, with a minute embryo 

 in hard albumen. Stems usually hollow. Leaves alternate, mostly com- 

 pound, the petioles expanded or sheathing at base ; rarely with true 

 stipules. Umbels usually compound, in which case the secondary ones 

 are termed umbellets ; the whorl of bracts which often subtends the gen- 

 eral umbel is the involucre, and those of the umbellets the involucels. The 

 base of the styles is frequently thickened and cushion-like, and called 

 the stylopodium. In many the flowers are dichogamous, i. e. the styles 

 are protruded from the bud some time before the anthers develop, an 

 arrangement for cross-fertilization. A large family, some of the plants 

 innocent and aromatic, others with very poisonous (acrid-narcotic) prop- 

 erties. The flowers are much alike in all, and the fruits, inflorescence, 

 etc., likewise exhibit comparatively small diversity. The family is con- 

 sequently difficult for the young student. 



I. Fruit with the secondary ribs the most prominent, winged and armed with 



barbed or hooked prickles, the primary ribs filiform and bristly. 



1 . Daucus. Calyx-teeth obsolete. Fruit flattened dorsally. Seed-face flat. 



2. Caucalis. Calyx-teeth prominent. Fruit flattened laterally. Seed-face deeply sulcate. 



II. Fruit with primary ribs only (hence but 3 dorsal ones on each carpel). 



* Fruit strongly flattened dorsally, with the lateral ribs prominently winged. 



i- Caulescent branching plants, with white flowers. 

 M- Lateral wings distinct ; oil-tubes usually more than one in the intervals. 



3. Angelica. Stylopodium mostly depressed, but the disk prominent and crenulate 



Dorsal ribs strong. Stout perennials, with mostly coarsely divided leaves. 



4. Conioselinum. Stylopodium slightly conical. Dorsal ribs prominent. Tall slender 



glabrous perennial ; leaves thin, finely pinnately compound. 



*+ *+ Lateral wings closely contiguous ; oil-tubes solitary ; stylopodium thick-conical. 



5. Tiedemannia. Dorsal ribs apparently 5, filiform. Smooth swamp herbs with leaves 



few or reduced to hollow cylindrical petioles. 



6. Heracleum. Dorsal ribs filiform, the broad wings with a marginal nerve. Oil-tubes 



obclavate. Petals conspicuous. Tall stout perennials, with large leaves. 



- - Caulescent branching plants, with depressed stylopodium and yellow flowers. 



7. Pastinaca. Fruit with filiform dorsal ribs, thin wings, and solitary oil-tubes. 



8. Polytsenia. Fruit with a thick corky margin, obscure dorsal ribs, and very numer- 



ous oil-tubes. 

 --)- Acaulescent or nearly so, with filiform dorsal ribs, thin wings, and no stylopodium. 



9. Peucedanum. Flowers white or yellow. Low western plants, of dry ground, with 



thick roots and finely dissected leaves. 



* * Fruit not flattened either way or but slightly, neither prickly nor scaly. 



i- Ribs all conspicuously winged ; stylopodium depressed or wanting 

 10. Cymopterus. Low and glabrous, mostly cespitose perennials, with pinnately com- 

 pound leaves and white flowers. Oil-tubes 1 to several. Western. 



II. Thaspium. Tall perennials, with ternately divided or simple leaves, and yellow flow- 



ers (rarely purple). Oil-tubes solitary. 



