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

20. Flowers in a single, small (4–40 mm long), dense head or spike terminating an elongate naked
scape, the head or spike either cone-like with numerous, overlapping, brownish, thin, ± woody
KEY TO MONOCOTS
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bracts (subtending yellow flowers) OR head whitish or grayish due to numerous hairs on the
subtending involucral bracts and flower parts.
21. Inflorescence cone-like, with spirally imbricated, brownish, thin, ± woody bracts, usually
with a single yellow flower exposed per inflorescence __________________________ (Xyris) Xyridaceae
21. Inflorescence a small whitish or grayish head, not cone-like, lacking brownish woody bracts,
without yellow flowers ___________________________________________ (Eriocaulon) Eriocaulaceae
20. Flowers not in a single, small, dense head or spike terminating an elongate naked scape; inflorescence
neither cone-like with numerous overlapping brownish bracts subtending yellow
flowers nor whitish nor grayish due to numerous hairs on the bracts and flower parts.
22. Plants large (1–3 m tall) erect emergents with an extremely dense, large (12–40 cm long),
brownish, cylindrical spike with thousands of very tiny flowers (cat-tails) ___________ (Typha) Typhaceae
22. Plants not as above, without a large, brown, cylindrical spike.
23. Flowers and fruits in the axils of imbricate (= overlapping) or distichous (= 2-ranked)
scales, concealed by the scales at least when young; fruits 1-seeded; perianth absent or
represented by bristles or small scales (grasses and sedges).
24. Stems typically round or flat in cross-section but never triangular, typically jointed
(nodes obvious), with hollow or solid internodes; leaves usually 2-ranked, with
sheaths normally split lengthwise on the side opposite the blade; each flower usually
subtended by 2 scales _________________________________________________ Poaceae
24. Stems round or often triangular, typically not jointed, with solid internodes; leaves
usually 3-ranked, with sheaths continuous around the stem or splitting only in age
OR leaves reduced to sheaths only; each flower usually subtended by 1 scale ______ Cyperaceae
23. Flowers and fruits not in the axils of imbricate or distichous scales, not concealed by
scales, or if so, fruits more than 1-seeded; perianth absent or present, sometimes petallike
or with conspicuous petals.
25. Inflorescence a fleshy spike (= spadix) of numerous, small, imperfect flowers, the
inflorescence enclosed in a conspicuous, specially modified bract (= spathe) or diverging
at an angle from the side of a spathe-like structure (in Orontium, which has
a conspicuous yellow spadix, the spathe is apparently absent).
26. Plants with elongate, linear, sword-like, parallel-veined leaves; spadix diverging
from the side of, but not enclosed in, an elongate, linear, spathe-like structure
___________________________________________________________ (Acorus) Acoraceae
26. Plants without elongate, linear, sword-like, parallel-veined leaves; spadix enclosed
in a spathe (except in Orontium) _________________________________________ Araceae
25. Inflorescence not a fleshy spike; flowers usually perfect (sometimes unisexual); inflorescence
usually neither enclosed in a spathe nor diverging at an angle from the
side of a spathe-like structure.
27. Plants emergent aquatics with 2-ranked, linear leaves and flowers in several
dense, globose, unisexual heads ________________________ (Sparganium) Sparganiaceae
27. Plants not as above.
28. Corollas absent (perianth absent or 28-merous and inconspicuous); plants
aquatic with submersed or floating leaves; fruits drupe-like, 1-seeded.
29. Leaves all submersed OR some floating, variable in width, from 0.2–45
mm wide; inflorescence with flowers in 2–5 whorls on peduncle elongated
above water surface; perianth 4-merous, though inconspicuous;
stamens 4 __________________________________________ Potamogetonaceae
29. Leaves all submersed, all thread-like, 0.2–0.5 mm wide; inflorescence
with flowers in 1 whorl on peduncle below water surface; perianth parts
absent; stamens 2 ____________________________________ (Ruppia) Ruppiaceae