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

SELAGINELLA/SELAGINELLACEAE
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Pseudolycopodiella caroliniana (L.) Holub, (of Carolina, because its type specimen came from the
“Carolinas,” a region which historically included much of the se U.S.—Nelson 2000), slender bog
club-moss, carolina club-moss, slender club-moss. Plant perennial; horizontal stems evergreen at
least at apex, short-creeping, flat on ground, rooted throughout from lower surface, densely covered
with leaves, 8–12 mm wide including leaves; horizontal stem leaves dimorphic, the lateral
leaves spreading and appearing 2-ranked, lanceolate to lanceolate-ovate, 3.5–7 mm long, 1.2–2.1
mm wide, entire; median leaves smaller, ascending; upright shoots (serving as peduncles) unbranched,
scattered along stems, 5–30 cm long, with only scattered, scale-like, subulate leaves;
strobili solitary, terminating peduncles, slender, 9–80(–120) mm long, 2.5–5(–8) mm wide including
sporophylls; sporophylls diverging, broadly ovate to deltate, acuminate, very different
from the leaves of the peduncles; sporangia reniform (= kidney-shaped), solitary at base of upper
side of sporophylls. Depressions in savannahs and open flat pinelands, in acidic soils, often with
sphagnum moss; Angelina, Jasper, Tyler (BRIT), Hardin, Henderson (BAYLU), and San Augustine
(TEX) cos. in s Pineywoods and Lee Co. (TEX) in the Post Oak Savannah; e U.S. from PA s to FL w
to AR and TX. Sporulating Jul-Sep. [Lycopodium carolinianum L.] m/296
SELAGINELLACEAE Willk.
SPIKE-MOSS FAMILY
AAn ancient, cosmopolitan but primarily tropical and subtropical family currently treated as
a single genus with � 700 species (Valdespino 1993). According to Korall et al. (1999), “Greatest
diversity occurs in lowland to midmontane primary tropical rain forest, but this cosmopolitan
family is also widely distributed in subtropical, temperate, montane, and rarely subarctic regions.”
Selaginellaceae are usually terrestrial or epiphytic, superficially moss-like vascular
plants bearing spores differentiated into microspores and megaspores (plants heterosporous).
The leaves usually have a single vein and ligules (= minute, tongue-like basal protuberance on a
leaf; the function is uncertain) are present. Recent molecular evidence supports the monophyly
of the Selaginellaceae (Korall et al. 1999). This family is apparently only distantly related to the
Lycopodiaceae and Isoetaceae.
FAMILY RECOGNITION IN THE FIELD: superficially somewhat moss-like, small herbs with numerous,
scale-like, 1-veined leaves; stems terminating in � 4-angled, spore-producing cones.
REFERENCES: Alston 1955; Correll 1956, 1966a; Jermy 1990b; Valdespino 1993; Korall et al. 1999.
SELAGINELLA P. Beauv. SPIKE-MOSS
East TX species small (ca. 12 cm or less tall), terrestrial or lithophytic (= growing on rocks)
(plants epiphytic elsewhere); stems leafy; vegetative leaves small, with ligule on adaxial side
near base, all alike or of 2 kinds; sporophylls (= spore-bearing leaves) modified, in strobili (=
cones) at branch tips; sporangia solitary in axils of sporophylls, of 2 kinds (microsporangia and
megasporangia).
[AAA]Selaginella, the only extant genus in the family, has an extremely long history in the fossil
record—fossils resembling Selaginella are known from the Carboniferous Period onwards
(Thomas 1992). It is currently most diverse in the tropics. A number have xerophytic (= drought
tolerance) adaptations and some are well known as “resurrection” plants, capable of reviving
after long periods of desiccation. Because of its heterogeneity, some authorities (e.g., Skoda 1997)
recommend splitting Selaginella into several genera. Small (1938), for example, separated S.
apoda and similar species into the genus Diplostachyum, and Thomas (1992) argued that, “The
presence of both isophyllous and heterophyllous Selaginella-like plants in the Carboniferous
[ca. 300 million years ago] supports the idea that the genus should be divided into at least two
genera.” However, splitting the genus would require name changes for all but two species (i.e.,
hundreds of name changes—J. Peck, pers. comm.), and we are following most recent authors