18 Order LILIALES 
12. Potamogeton dimorphus Raf. 
Lincoln. 
13. Potamogeton pectinatus L. 
Common in the sand-hill regions. Alliance; Cherry county; Craw- 
ford; Halsey; Kennedy; Thedford; Valentine; Whitman. 
14. Potamogeton interior Rydb. 
A western form, reported for Nebraska in Gray’s Manual. 
15. Potamogeton interruptus Kitaibel. 
In the mill-pond at Neligh. 
2. Ruppia. 49. 
1. Ruppia occidentalis S. Wats. 
In salt or alkaline ponds. Alliance; Sheridan county. 
3. Zannichellia. 50. 
1. Zannichellia palustris L. 
In ponds throughout the state. Banner county; Broken Bow; Cody’s 
Lakes; Lincoln; Simeon. 
LILIALES. 
Perianth segments, at least the inner, corolloid. 
Perianth segments all corolloid. 
Stamens 6, all alike. 1. Liliacezx. 
Stamens unlike or only 3. 2. Pontederiacez. 
Perianth segments unlike, the inner corolloid; the outer green. 
Leaves whorled or ovules numerous. 1. Liliacez. 
Leaves not whorled; ovules usually 2 in each cavity; petals 
soon withering, but persistent. 3. Commelinacee. 
Perianth segments scaly, green or brown, or wanting. 
Land or marsh plants with a scaly perianth. 4. Juncacee. 
Submerged water plants, perianth often wanting. 5. Naiadacezx. 
1. LILIACEAE. 
Lily Family. 
(Including Convallariacee and Melanthacez.) 
Flowers perfect; herbs without tendrils, never climbing. (Flowers 
polygamo-monecious in Zygadenus.) 
Styles distinct, capsule 3-beaked. 1. Zygadenus. 
Styles united, or short or wanting. 
Sepals and petals nearly alike. 
Plants with bulbs or corms. 
Flowers in umbels with scarious involucres. 
Ovules 2 in each cavity of the ovary; foliage onion- 
scented. 3. Allium. 
Ovules many in each cavity of the ovary; foliage not 
onion-scented. 4. Nothescordum. 
Flowers not in involucrate umbels, often solitary. 
Stems leafy; leaves several. 
Tall herbs; anthers attached near the middle, versatile. 
5. Lilium. 
