60 UMBELLIFERAE. 



O. rafinesquii Engelm. Prickly Pear. Prostrate, green; joints obovate to 

 suborbicular or oval; leaves spreading-, subulate; spines axillary, 1-5 together; 

 prickles tufted, axillary, reddish brown; flowers large, yellow, with a reddish 

 center; stamens shorter than the petals; stigmas 4-10; fruit fleshy, edible. 

 Sandy soil; June-July; infrequent; Muscatine and Lyon counties. (O. humi- 

 fiisa Raf.) 



O. fragilis (Nutt.) Haw. Prostrate or decumbent; joints ovate, nearly 

 terete or flattish; leaves small, reddish; flowers yellow, smaller than those of 

 the preceding; fruit dry at maturity. Dry soil; July-August; common; Lyon 

 county. 



AIZOACEAE A. Br. Carpet-weed Family. 



Mostly prostrate and branching herbs, with opposite or verticillate 

 leaves, and small regular perfect flowers, either solitary, cymose or 

 glomerate. Calyx of 5 sepals, free from the ovary. Petals wanting. 

 Represented in our flora by the genus Mollugo L. 



M. Verticillata L. Carpet-weed. Prostrate, much branched, annual, form- 

 ing patches; leaves spatulate, whorled at the joints; pedicels slender, 1-flow- 

 ered, clustered with the leaves; stamens mostly 3; stigmas 3; capsule 3-eelled, 

 3-valved; seeds reniform. Sandy shores, waste places; July-September; 

 common. This species is included by different botanists under Ficoideae or 

 Caeyophyllaceae. 



UMBELLIFERAE B. Juss. Carrot Family. 

 Herbs, with usually hollow stems, alternate compound or simple leaves, 

 sheathing petioles, and small flowers in compound umbels, rarely in 

 heads. Calyx adherent to the ovary, limb obsolete or 5-toothed. Petals 

 and stamens 5, iuserted on a fleshy disk which covers the ovary. Styles 

 2, distinct or united at their thickened bases. Ovary 2-celled, 2-ovuled. 

 Fruit dry, consisting of 2 coherent carpels. A well defined but difficult 

 order. 



* Flowers white. 

 t Fruit flattened dorsally. 

 Daucus. Leaves pinnately decompound; calyx 5-toothed; fruit prickly along the ribs. 

 Coniosblinum. Leaves 2-3-pinnately decompound; fruit winged on the lateral lobes. 

 Tiedemannia. Leaves simply pinnate. 

 Heracleom. Leaves large, ternately compound; flowers large. 



•f f Fruit flattened laterally. 

 Sidm. Leaves once pinnate ; ribs prominent, equal, corky. 

 C »kom. Leaves decompound ; fruit ovoid or oval ; ribs filiform, inconspicuous . 

 Cicuta. Leaves pinnately compound, the veins running to the notches; ribs flattish, 



corky. 

 Conidm. Stems spotted ; leaves tripinnately dissected ; ribs wavy. 



t + + Fruit linear-oblong, slightly flattened laterally. 

 Cryptotaenja. Leaves 3-foliolate; fruit glabrous; ribs obtuse, equal. 

 BEBuiiA. Aquatics; leaves simply pinnate; fruit globrous, nearly galbose; ribs incon 



spicuous. 

 Chaerophyllum. Leaves temately decompound; fruit glabrous. 

 Osmorrhiza. Leaves biternately divided ; fruit bristly. 



t t t t Fruit ovate or obovate. 

 Eryngium. Leaves parallel-veined, coriaceous, bristly-toothed; flowers in dense 

 bracted globose heads. 



* * Flowers yellow. 

 f Fruit globular, armed with hooked prickles. 

 Sanioula. Leaves palmately divided; flowers greenish yellow. 



