keys to the vascular plants of east texas - Botanical Research ...

314 KEY TO MONOCOTS
8. Plants not climbing vines.
10. Plants aquatics growing completely submersed; leaves opposite or whorled.
11. Leaves in distinct whorls of 3–8; flowers (staminate and/or pistillate) borne
at the water surface on a thread-like stalk 3–6 cm long; perianth (staminate
and/or pistillate) 3–10 mm long, white or translucent, visible with the naked
eye _______________________________________________________ Hydrocharitaceae
11. Leaves opposite (some can occasionally appear whorled where branches
arise); flowers sessile or subsessile, borne underwater; perianth absent or
minute, clearish or greenish, virtually indiscernable without a lens.
12. Leaves obviously toothed to the naked eye _____________ (Najas) Hydrocharitaceae
12. Leaves not obviously toothed to the naked eye.
13. Leaf blades usually very minutely denticulate (under a scope), sheathing
basally; fruits not curved, not short stipitate, without a beak; flowers
with a single carpel; sheathing stipules not present _________________ (Najas)
Hydrocharitaceae
13. Leaf blades entire, not sheathing basally; fruits curved, short stipitate
(= stalked), also with a beak to 1.5 mm long; flowers with 2–8 separate
carpels; sheathing stipules present ________ (Zannichellia) Zannichelliaceae
10. Plants terrestrial or aquatic, but if leaves completely submersed then alternate or
basal.
14. Plants free-floating aquatics with leaves in rosettes.
15. Leaves sessile, velvety-hairy; perianth absent _____________________ (Pistia) Araceae
15. Leaves distinctly petiolate, the petioles swollen OR not so, ca. as long as
the blades or longer, the blades glabrous; perianth present.
16. Petioles not swollen; leaf blades with a central disk of purplish spongy
tissue underneath; perianth greenish white to yellowish, at most 1.4
cm long _________________________________ (Limnobium) Hydrocharitaceae
16. Petioles swollen; leaf blades without a central disk of spongy tissue
underneath; perianth much larger, 4–6 cm long, bluish lavender, the
upper segment with a yellow spot, very showy _____ (Eichhornia) Pontederiaceae
14. Plants not free-floating, either terrestrial or aquatic, but rooted in substrate;
leaves variously arranged.
17. Plants completely submersed rooted aquatics with elongate, ribbon-like,
basal leaves 8–60(–nearly 100) cm long; flowers at the water surface, the
inflorescences never extending above the water _____ (Vallisneria) Hydrocharitaceae
17. Plants either terrestrial or aquatic, with leaves various; if aquatic, then flowers
usually held above the water surface.
18. Inflorescence a peduncle terminated by a winged or ribbed spathe
containing a single flower with white to pinkish petals 2–3 cm long;
leaves usually all submersed, ± basal, petiolate, lanceolate to broadly
ovate, with curving, ± parallel veins; rare introduced species known
in East TX only from Jefferson Co. near se margin of area _______________ (Ottelia)
Hydrochariaceae
18. Inflorescence and leaves various, not as above; including native and
introduced species widespread in East TX.
19. Plants without obvious leaves (only bladeless sheaths present);
stems unbranched; perianth absent or of inconspicuous bristles
or small scales _________________________________________ Cyperaceae
19. Plants usually with obvious leaves (these rarely reduced to bracts);
stems branched or unbranched; perianth various, ranging from
conspicuous to absent.