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

970 POACEAE/LEPTOCHLOA
the U.S. May–Oct. [Diplachne fascicularis (Lam.) P. Beauv., L. fascicularis (Lam.) A. Gray] According
to Snow (1997), this is the most common Leptochloa in North America.
subsp. uninervia (J. Presl) N. Snow, (one-nerved), MEXICAN SPRANGLETOP. Similar to subsp.
fascicularis and distinguished as in the key to subspecies. Mud, sometimes alkaline or
subsaline; Brazos, Jefferson (TAES), Red River (Snow 1997), Bexar, Grayson, and Williamson
(Turner et al. 2003) cos.; mainly s 1/2 of TX, scattered elsewhere; throughout s 1/2 of the U.S.,
also NJ, MA, ME, and OR. Spring–summer(–fall). [Diplachne uninervia (J. Presl) Parodi, L.
uninervia (J. Presl) Hitchc. & Chase] While specimens intermediate with subsp. fascicularis are
occasionally seen, the two “generally maintain their morphological distinctness when growing
together” (Snow 1997).
Leptochloa nealleyi Vasey, (for Greenleaf Alley Nealley, 1846–1896, possibly the earliest botanist
at Texas A&M), NEALLEY’S SPRANGLETOP. Tufted annual; culms 30–150(–250) cm tall, stiffly
erect; ligule 1.5–3 mm long, lacerate; inflorescence branches 25–75 or more; spikelets 2.8–3.4
mm long; glumes and lemmas awnless, the lemmas sometimes apiculate. Usually in wet areas
such as ditches, pond margins, or marshes; Gonzales, Jefferson, Wilson (Snow 1997), Bastrop,
and Harris (Turner et al. 2003) cos. near s boundary of East TX; this primarily coastal species is
otherwise known in TX only from the Gulf Prairies and Marshes and South TX Plains; AZ, LA,
and TX. Apr–Nov. “The numerous, short, stiffly ascending or erect panicle branches make
Leptochloa nealleyi easy to identify” (Snow 2003a).
Leptochloa panicea (Retz.) Ohwi, (of Panicum—panic grass), RED SPRANGLETOP, SLENDER GRASS.
Tufted annual; culms 10–80(–150) cm long, erect to spreading and ascending; ligule 0.5–2(–3.2)
mm long, lacerate or ciliate; inflorescence branches 10–70(–100), scattered; spikelets 1.5–3.5(–4)
mm long, widely spaced and only slightly overlapping; glumes and lemmas usually awnless or
nearly so. Moist soils and mud; nearly throughout TX; widespread in the s 2/3 of the U.S. Late
spring–fall. [L. attenuata (Nutt.) Steud., L. filiformis (Lam.) P. Beauv., L. mucronata (Michx.) Kunth]
This species has recently undergone several nomenclatural changes. While long known as L.
filiformis, Snow and Davidse (1993) indicated that the correct name was L. mucronata. More recently,
Snow (1997, 1998a), based on detailed revisionary work, concluded that the correct name
is L. panicea and that there are two subspecies in the U.S., subsp. brachiata (Steud.) N. Snow and
subsp. mucronata (Michx.) Nowack. Yatskievych (1999) and Snow (2003a) recognized the two
subspecies and differentiated them as shown in the following key (included for those wishing
to identify subspecies). However, we have been unable to find consistent differences in TX material.
Many East TX specimens appear somewhat intermediate, the spikelets are � awnless,
there is usually no pubescence on the lemmas, and the upper glume is either shorter or longer
than the rest of the spikelet (this sometimes varying on the same plant). As a result, we are not
formally recognizing subspecies. However, L. Brown (pers. comm.) noted that there are collections
from Anderson and Fort Bend (SBSC) cos. that are discernable as subsp. mucronata.
1. Glumes lanceolate to narrowly elliptic, sharply pointed at the tip but awnless, the upper glume
usually shorter than the rest of the spikelet; lemmas 1.3–1.7 mm long, distinctly hairy along the
veins; caryopses usually with a narrow, shallow ventral groove, smooth, the apices broadly obtuse
to acute ________________________________________________________________ subsp. brachiata
1. Glumes linear to narrowly lanceolate, tapered to a minute awn at the tip, the upper glume usually
longer that the rest of the spikelet; lemmas 0.9–1.2 mm long, nearly glabrous along the
veins, except at the base; caryopses without a ventral groove, often somewhat coarsely rugose,
the apices broadly obtuse _____________________________________________________ subsp. mucronata
Leptochloa panicoides (J. Presl) Hitchc., (resembling Panicum—panic grass), AMAZON SPRANGLE-
TOP. Tufted annual; culms 40–100(–110) cm tall, usually erect; ligule an erose membrane ca. 2–4
mm long; glumes and lemmas awnless, the lemmas usually mucronate. Wet areas such as