UMBELLIFER^E. 41 



OED. 33. UMBELLIFER^;. 



The plants composing this Order are difficult to determine, 

 owing to the parts relied upon for the distinguishing of the Genera 

 being very minute. The leaves are usually much cut. Flowers 

 in umbels with bracts or involucres at the base. A simple umbel 

 has the stalks from ooe point, bearing flowers; in a compound 

 umbel these stalks again bear a second series, with bracts or 

 partial involucres at their base ; the general involucre being at 

 the base of the first or primary umbel. 



The fruit is composed of 2 carpels (mericarps) joined by their 

 faces (commissure) suspended from a bi-partite axis (carpophore), 

 readily seen when ripe ; each carpel is marked on the back by 5 

 more or less prominent ribs, with ducts or receptacles (vittas) of 

 oily or resinous matter in stripes between, sometimes wanting. 

 Albumen horny ; being plain, furrowed, or involute on the inner 

 face. 



The key here given is purely artificial; numerous divisions, 

 although natural, are apt to confuse a student. By referring to 

 the excellent plates of the Genera in Hook. & AT. Brit. Fl. , the 

 subject may be rendered comparatively simple. 



A. Fruit covered with bristly ribs or prickles. 

 * Vittce none. Umbles simple. 



2. SANICULA. Cal. of 5, leaf -like teeth. Involucre none. 



3. ERYNGTUM. Umbels in dense heads. Tnvolucral leaves, 

 3-lobed, very large. Le. prickly. 



** Vittce single. Umbels compound. 



24. DAUCUS. General involucre large, mostly pinnatifid. Fruit 

 dorsally compressed, prickles long, flat, often hooked at the 

 apex ; interstices with bristles. 



25. TORILIS. General and partial involucres many-leaved, small. 

 Outer petals longer than the inner. Fruit slightly laterally 

 compressed. 



B. Fruit very much compressed, 

 a. Umbels simple. 



1. HYDROCOTYLE. Fruit laterally compressed, orbicular. Le. 

 simple, peltate. 



b. Umbels compound. 



15. ANGELICA. General involucre of 2 3 leaves; partial ones 

 narrow and short. Fruit with 2 wings on each side. 



16. PEUCEDANUM. Partial involucre many-leaved. Fruit with 

 one wing on each side, and 3 dorsal ribs on each carpel. 



