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

358 OPHIOGLOSSACEAE/OPHIOGLOSSUM
variable species (Wagner & Wagner 1993), one form of which (forma dissectum—northern entity
occurring as close as c AR—Peck, pers. comm.) is highly dissected and quite distinctive.
However, the only form occurring in TX (forma obliquum, previously treated as a variety)
closely resembles B. biternatum. As a result, B. dissectum and B. biternatum have often been
confused (particularly immature plants). According to Taylor (1984) “… there do not appear to
be any stable characters which will always clearly distinguish these two taxa.” Thomas (1980)
indicated that the two intergrade and that some individual specimens puzzle even the experts.
Nauman et al. (2000) lumped B. dissectum into B. biternatum saying, “they intergrade in Florida
to such an extent that two species cannot be maintained.” However, according to W.H. Wagner
Jr. (pers. comm.) and Wagner and Wagner (1993), B. dissectum has leaves that are more dissected
and the ultimate segments usually trowel-shaped (rarely linear), apically more pointed, and
with the margins more lacerate. Likewise, J.H. Peck (pers. comm.) indicates that two species are
distinct and that mature reproductive material can usually be distinguished without difficulty.
We are therefore following Wagner and Wagner (1993) and J.H. Peck (pers. comm.) in recognizing
B. dissectum as a distinct species. m/277
Botrychium lunarioides (Michx.) Sw., (resembling moonwort—Botrychium lunaria), WINTER
GRAPE FERN, PROSTRATE GRAPE FERN. Roots 20–30, yellow to brown; leaves appearing in late fall,
overwintering and then dying in early spring (plant wholly underground and dormant for 8–9
months per year); sterile blade portion usually pale green, short-stalked, fleshy, to 12 cm wide,
2–3-pinnate-pinnatifid; ultimate leaf segments fan-shaped, with midvein absent, denticulate,
rounded at apex. Open closely cut grassy areas, often in cemeteries; n Pineywoods and Post Oak
Savannah w to Bastrop, Falls, Hunt, Kaufman, Lee, Limestone, Navarro (BAYLU), and Milam
(Holmes et al. 1996) cos. on e edge of Blackland Prairie; se U.S. from NC s to FL w to OK and TX.
Spores maturing Feb–Apr. [Holubiella lunarioides (Michx.) Skoda] According to Wagner and
Wagner (1993), a “… peculiarity of this species is the tendency for the sporophores to remain
curled in late fall and early winter and to become erect in February.” This species was first collected
in TX (San Augustine Co.) in 1972 (Thomas 1979). It was only recently reported from the
Blackland Prairie by Holmes et al. (1996), who greatly expanded its known distribution within
TX; it is now widely known in East TX. Wagner (1992) considered B. lunarioides to be distinct
enough to place it in its own section. This species is easily overlooked. Nelson (2000) indicated
that the “most effective way to find this fern is to search for it in closely cut lawns, especially
cemeteries, by crawling on hands and knees or by laying one’s face close to the ground, then
looking laterally across the top of the grass for the fertile frond segments.”
Botrychium virginianum (L.) Sw., (of Virginia), RATTLESNAKE FERN, VIRGINIA GRAPE FERN, COM-
MON GRAPE FERN. Plant erect, 8–75 cm tall; roots 15 or fewer, yellow to brown; leaves seasonal,
appearing in early spring and dying in summer; sterile blade portion pale green, sessile, thin,
herbaceous, 4–30 cm long and wide, 3–5-pinnate-pinnatifid; ultimate leaf segments linear,
with midvein present, serrate to lacerate, pointed at apex. Moist, rich woods and thickets;
Pineywoods w to Cross Timbers and Prairies (e.g., Tarrant Co.—BRIT); also e Edwards Plateau;
throughout most of Canada and the U.S. Spores maturing Apr–Jun. The common name is probably
derived from a resemblance of the clusters of sporangia to the rattles of a rattlesnake. Alternatively,
it has “been reported that a salve made by boiling the roots of the plant was used by
the Cherokee Indians in the treatment of snake bites” (Nelson 2000).
OPHIOGLOSSUM L. ADDER’S-TONGUE
Plants small, East TX species to ca. 25 cm tall; blade portion of leaf simple; fertile portion of leaf
consisting of an elongate stalk terminated by an unbranched, linear, spike-like, sporangiabearing
region.
AA nearly cosmopolitan, but mainly tropical and subtropical genus of 25–30 species (Wagner
& Wagner 1993). Ophioglossum species have the highest chromosome numbers known for