Spring Flora of Oklahoma 
121 
around the top of the ovary. Petals 5. Stamens 5, in¬ 
serted on the disk, which is borne by the ovary. Ovary 
2-celled and 2-ovuled, ripening into 2 achene-like carpels, 
which separate from each other. Each carpel bears 5 
longitudinal ribs, in the farrows, between which sec¬ 
ondary ribs frequently occur. Fruit either flattened lat- 
'erally (at right angles to the commissure), or dorsally 
(parallel to the commissure), or nearly terete (not flat¬ 
tened). Pericarp membranous or corky-thickened, usu¬ 
ally containing oil-tubes between the ribs or under the 
ribs, and on the commissural side. Oil-tubes sometimes 
irregularly scattered, sometimes none. 
I. Fruit ribless, covered with hooked prickles. 
I. Sanicula. 
II. Fruit ribbed, at least its beak, the ribs rarely ob¬ 
solete. Fruit not bristly. II. Chaerophyllum. » 
A. Fruit much flattened dorsally, parallel with the 
commissure. Aculscent or nearly so. 
III. Cogswellia. 
B. Leafy-stemmed; stylopodium conic or depressed. 
IV. Pleiotaenia. 
0. Fruit not flattened, or flattened laterally (at 
right angles to the commissure). 
1. Petals white, greenish-white or rarely pinkish. 
a. Fruit nearly terete, not flattened either lat¬ 
erally or dorsally, or very slightly flattened. 
V. Cynosciadium. 
b. Fruit laterally flattened. 
Fruit tubercled or bristly. 
Seed-face concave. VI. Spermolepis. 
Seed-face flat. VII. Ammoselinum. 
