316 IOWA ACADEMY OF SCIENCE Vor./ XXVIII, 1921 
5. 
Evs. floating or submerged 
Potamogetonacese 
S. 
Lvs. not floating or submerged 
6 
6. Lvs. linear with no distinction between stalk 
and blade. Fls. without petals, in heads 
7 
6. Fls. with petals, in racemes or panicles 
Alismataceae 
7. 
Heads long and narrow 
Typhaceae 
7. 
Heads globular 
Sparganiaceae 
8. Fls, stalkless on a thick axis forming a spike 
9 
8. Fls. not on thick axis 
10 
9. 
Spike cylindric with seed-bearing fls. at base and 
pollen-bearing fls. above; axis woody 
Typhaceae 
9. 
Axis of spike fleshy, soft 
Araceae 
10. Climbing or twining stems 
11 
10. Non-twining stems 
12 
11. 
Fls. small in racemes or panicles 
Dioscoreaceae 
11. 
Fls. small, green, in globular umbels 
12. Fls. greenish or brown, chaffy; lvs. less than 
Liliacea: 
5 mm, wide or none 
Juncaceae 
12. Fls. with conspicuous perianth 
13 
13. 
Ov. inferior, appearing below perianth as a swell- 
ing at apex of stalk 
14 
13. 
Ov. superior, in center of fl. and separate from 
perianth 
19 
14. Lvs. grasslike, 5 mm. or less wide 
15 
14. Lvs. broader than 5 mm. 
16 
15. 
Fls. yellow, 1-2 cm. across 
Amaryllidaceae 
15. 
Fls. blue or white; if yellow, 4-6 cm. long 
Iridaceae 
16. Lvs. with one edge toward stem; stam. 3 
Iridace^ 
16. Lvs. with a flat side toward stem 
17 
17. 
Anther-bearing stamens 6 
Amaryllidaceae 
17. 
Anther-bearing stamens 1 or 2 
18. Plants 6-20 dm. tall; lvs. 1.5 dm. wide or 
18 
more ; (!:ult. 
18. Plants 1-10 dm. tall; lvs. 8 cm. or less wide. 
Cannaceae 
Native 
Orchidaceae 
19. 
Fls. with green sepals 
20 
19. 
Fls. with sepals and petals colored alike 
Liliaceae 
20. Stems leafy; fls. clustered ■ Commelinacese 
20. Stems naked, with three Ivs. and 1 fl. at top Liliacese 
Grin NELL College 
Department oe Botany 
