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

SPIRANTHES/ORCHIDACEAE
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12. Lip usually widest near apex or the lateral margins parallel, thin and membranous,
white, usually marked or veined with green (usually with distinctive diverging green
lines) _________________________________________________________________ S. praecox
8. Inflorescence with flowers multi-ranked (= inflorescence with the flowers so densely spiraled as
to produce the appearance of 2–4 vertical rows or ranks of flowers spiraling up the inflorescence).
14. Flowers remaining unopened in all stages; perianth pale yellowish __________ S. cernua (peloric form)
14. Flowers opening in normal manner; perianth white to ivory or cream, the lip often with
yellowish to greenish center or markings.
15. Lateral petals � obovate to ovate or suborbicular, distinctly narrowest at base, with a
central green stripe (strip rarely absent); lip 5–7 mm long; in side view the sepals
extending further (appearing longer) than the petals; rare endangered species endemic
to a few counties in the s part of the Post Oak Savannah and one in the
Pineywoods ______________________________________________________________ S. parksii
15. Lateral petals linear to lanceolate, elliptic-lanceolate, or lance-oblong, not distinctly
narrowest at base, without a central green stripe; lip 5–16 mm long; in side view all
perianth parts extending about the same distance; including species common and
widespread throughout East TX.
16. Perianth 5–6.1 mm long, pure white, including lip; plants delicate, slender, 5–40
cm tall; leaves present at flowering time; spike 15 mm or less in diam.; flowers
unscented _____________________________________________________________ S. ovalis
16. Perianth 5–15(–18) mm long, white to ivory, cream, creamy green, or green, the
lip with a yellow, greenish yellow, or yellow-green center or marked with green
veins; plants often large and stout (for a Spiranthes), 7–100+ cm tall; leaves present
OR absent at flowering time; spike usually much � 15 mm in diam.; flowers unscented
or scented.
17. Lip usually widest near apex or the lateral margins parallel, thin and membranous,
white or creamy green to green, usually marked or veined with green
(usually with distinctive diverging green lines); plants flowering Apr–Jun.
18. Perianth 5.5–8.5(–11) mm long, white, the lip usually with green veins
near apex ______________________________________________________ S. praecox
18. Perianth 10–16.5 mm long, creamy green to green, the lip with darker
green veins near apex ___________________________________________ S. sylvatica
17. Lip usually widest near base, often fleshy-thickened, white with a yellow, greenish
yellow, or yellow-green center; plants flowering (late Aug–)Oct–Dec(–Jan).
19. Lateral sepals spreading, the tips arching upward and angled away from
the rest of the perianth; flowers slender, not inflated, strongly fragrant;
leaves usually absent at flowering time; lip not constricted near the middle,
with small basal tuberosities (� short conical knobs); plants typically in
calcareous, slightly alkaline soils, usually in grasslands __________ S. magnicamporum
19. Lateral sepals appressed, oriented parallel to the rest of the perianth; flowers
appearing inflated, strongly fragrant OR not so; leaves present OR
absent at flowering time; lip not constricted OR slightly to distinctly constricted
near the middle, often with prominent basal tuberosities (usually
somewhat inward-curving); plants often in sandy soils or very wet
situations, in various habitats.
20. Leaves all basal or 1–2 near very base of stem, usually not persisting
until flowering time; petioles less than 6 mm wide; flowers scentless
or only faintly fragrant; lip (when flattened) widest basally, usually
slightly to distinctly constricted near the middle and then slightly
widened at the apex; in various habitats throughout East TX ___________ S. cernua