620 AMMIACEAE. Vol. II. 



at maturity along the plane of their contiguous faces (the commissure). Fruit 

 either flattened laterally (at right angles to the commissure), or dorsally (parallel 

 to the commissure), or nearly terete (not flattened). Carpels after parting from 

 each other supported on the summit of a slender axis (the carpophore), each with 

 5 primary ribs in their pericarps (rarely ribless), and in some genera with 4 addi- 

 tional secondary ones, the ribs or some of them often winged. Pericarp mem- 

 branous or corky-thickened, usually containing oil-tubes between the ribs, or 

 under the ribs and on the commissural sides, sometimes irregularly scattered, some- 

 times none. Seeds i in each carpel, usually adnate to the pericarp, their inner 

 faces flat or concave ; seed-coat thin ; endosperm cartilaginous ; embryo small, 

 placed near the hilum ; cotyledons ovate, oblong or linear. 



About 250 genera and probably 2000 species, of wide geographic distribution, not abundant in 

 tropical regions. Tlie mature fruit is necessary for the certain determination of most of the genera 

 and many of the species, the flowers being very much alike in all, and the leaves exhibiting great 

 diversity in the same genus. The family is also known as Umbelliferae, a misleading designation, 

 many other plants bearing their flowers in umbels, and several of its genera bear them otherwise. 



1. Fruit ribless, scaly; flowers densely capitate (Eryngieae). i. Eryngium. 



2. Fruit ribbed or rarely ribless, not scaly ; flowers umbelled, the umbels sometimes compact. 



A. Fruit ribless, covered with hooked prickles (Saniculae). 2. Sanicula, 



B. Fruit ribbed, at least its beak, the ribs rarely obsolete. 



a. Fruit with both primary and secondary ribs, the latter the more prominent, armed with hooked 



prickles, primary ribs bristly (Caucalieae). 

 Calyx-teeth obsolete ; fruit dorsally flattened. 3. Daucus. 



Calyx-teeth prominent ; fruit laterally flattened. 4. Torilis. 



b. Fruit with primary ribs only (Ammineae). 



* Fruit linear or linear-oblong, several times longer than wide. 

 Fruit bristly. 



Fruit with a beak much longer than the body. 5. Scandix, 



Fruit beakless, narrowed to the base. 6. Washingtonia. 



Fruit not bristly. 



Fruit beaked, the beak shorter than the body ; oil-tubes none. 7. Cerefolium. 



Fruit beakless, or short-beaked ; with oil-tuties. 



Annual herbs, with decompound leaves. 8. Chaerophyllum. 



Perennial herb, with 3-foliolate leaves. 9. Deringa. 



** Fruit oblong to ovoid or globose, not more than about twice as long as wide. 



t Fruit much flattened dorsally, parallel with the commissure. 

 Leaf-segments entire. 10. Pseudotdenidia, 



Leaf-segments toothed or incised, or leaves dissected. 

 Acaulescent or nearly so. 1 



Calyx-teeth obsolete : stylopodium none. 11. Cogswellia. 



Calyx-teeth distinct; stylopodium flat, evident. 12. Cynomarathrum. 



Leafy-stemmed ; stylopodium conic or depressed. 



Flowers yellow or greenish-yellow ; stylopodium depressed. 



Fruit with thickened corky margins, the ribs obscure ; perennial, native. 



13. Pleiotaenia. 

 Fruit thin-margined, the ribs distinct ; introduced plants. 



Annual; leaves finely dissected. 14. Anelhum, 



Biennial or perennial ; leaves pinnately compound with broad leaflets. 

 Umbels not involucrate. 15. Pastinacci. 



Umbels involucrate, the bracts deflexed. 16. Hipposelinum, 



Flowers white or greenish-white ; stylopodium mostly conic ; involucre none, or of a 

 ^ few small bracts, or deciduous ; perennials. 



Oil-tubes large, not extending to the base of the fruit. 17. Heracleum. 



Oil-tubes slender, extending to the base of the fruit or very nearly to the base. 

 Lateral wings of the fruit distinct, forming a double border. 



Leaves 2-3-pinnately decompound, with narrow segments ; stylopodium 



depressed-conic. 18. Conioselinum. 



Leaves ternately or pinnately compound, with broad segments ; stylopodium 

 depressed. 19. Angelica. 



Lateral wings of the fruit contiguous. 



Native marsh herbs ; leaves pinnate, or reduced to hollow phyllodes. 



20. Oxypolis. 

 Introduced field herb; leaves ternate. 21. Jmperatoria. 



ft Fruit not flattened, or flattened laterally (at right angles to the commissure). 

 t Petals yellow or greenish-yellow {sometimes deep purple in Thaspium). 

 Leaves entire, perfoliate in our species; fruit without oil-tubes. 22. Bupleurum. 



Leaves compound ; fruit with oil-tubes. 



Fruit not flattened, all its ribs winged ; stylopodium none. 23. Thaspium. 



Fruit laterally flattened, its ribs rot winged. 



Leaf-segments entire ; stylopodium none ; oil-tubes many. 24. Taenidia. 



Leaf-segments crenate, lobed or incised. 



Stylopodium none. 25. Zisia, 



Stylopodium present, conic or depressed. 



