1. Hippuris vulgaris L. Fig. 572. 



Stems submersed or partly emersed, erect, simple, 3-6 dm. tall, hollow, arising 

 from a creeping horizontal rhizome; herbage glabrous, usually pallid; leaves simple, 

 6 to 12 in a whorl, linear-attenuate. 5-35 mm. long, thick; flowers sessile in middle 

 and upper axils, usually perfect; petals none; stamen 1, inserted on anterior edge 

 of calyx; ovary inferior, crowned with the rimlike entire calyx; fruit 2-3 mm. long, 

 1-celled and 1 -seeded. 



Rooted in mud of shallow water in ponds and streams, marshes and wet mea- 

 dows, in N. M. (Rio Arriba, Taos, Santa Fe and San Juan cos.) and Ariz. (Apache 

 Co.), June-Aug.; widely distributed in the cooler parts of the Northern Hemi- 

 sphere. 



The seeds and occasionally the foliage are eaten by wildfowl. The usually dense 

 colony of plants also provide shelter for small animal life. 



Fam. 98. Umbelliferae Juss. Parsley Family 



Primarily herbaceous plants, acaulescent or caulescent, annual, biennial or 

 perennial, with commonly hollow stems; leaves alternate or rarely opposite or 

 basal, compound or sometimes simple, usually much-incised or -divided, with 

 usually sheathing petioles; flowers small, regular, in simple or compound umbels, 

 or the umbels sometimes proliferous or capitate; rays sometimes subtended by 

 bracts forming an involucre; umbellets usually subtended by bractlets forming an 

 involucel; calyx tube wholly adnate to the ovary; calyx teeth usually obsolete or 

 small; petals 5, usually with an inflexed tip; stamens 5, inserted on an epigynous 

 disk; ovary inferior, bilocular; styles 2, sometimes swollen at the base, forming a 

 stylopodium; fruit consisting of two mericarps united by their faces (commissure), 

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

 angles to the commissure) or terete, each mericarp with 5 primary ribs, one down 

 the back (dorsal rib), two on the edges near the commissure (lateral ribs) and two 

 between the dorsal and lateral ribs (intermediate ribs) and rarely with secondary 

 ribs, the ribs filiform to broadly winged and thin or corky; oil tubes obsolete or 

 present in the intervals (spaces between the ribs) and on the commissural surface, 

 rarely also in the pericarp; mericarps 1 -seeded, splitting apart at maturity, usually 

 suspended from the summit of a slender prolongation of the axis (carpophore). 



A cosmopolitan family of world-wide distribution consisting of at least 200 

 genera and perhaps 3,000 species. 



(Adapted mainly from various works published by Mildred E. Mathias and 

 Lincoln Constance.) 



1. Flowers and fruits borne in compound umbels or bracteate heads (2) 



1. Flowers and fruits borne in simple noncapitate umbels; leaves small and 



relatively simple (28) 



2(1). Flowers and fruits (or some of them) pedicellate; fruits more or less 

 evidently ribbed; calyx minute or obsolete (3) 



2. Flowers and fruits sessile or subsessile in dense bracteate heads or headlike 



umbellets; fruits with obsolete ribs, crowned by the prominent and 



persistent calyx and densely beset with scales or tubercles 



27. Eryngium 



3(2). Fruits terete to somewhat compressed laterally, the ribs not prominently 

 winged (4) 



3. Fruits strongly flattened dorsally, some or all of the ribs broadly winged (24) 



4(3). Fruits merely bristly-pubescent to glabrous (5) 



4. Fruits armed with uncinate bristles or prickles, or tuberculate, papillate or 



callous-toothed (22) 



1211 



