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

382 THELYPTERIDACEAE/MACROTHELYPTERIS
World (Thomas & Room 1986; Moran 1992, 2004; Wood et al. 2001; R. Helton, pers. comm.; H.
Elder, pers. comm.). � I
THELYPTERIDACEAE Pic. Serm.
MARSH FERN OR MAIDEN FERN FAMILY
East TX species terrestrial; stems (rhizomes) short- or long-creeping; leaves usually monomorphic
or nearly so (somewhat dimorphic in Thelypteris dentata); leaf blades 1-pinnate-pinnatifid,
2-pinnate-pinnatifid, or 2–3-pinnatifid near base, less divided distally, usually with an indument
(sometimes sparse) of transparent needle-like hairs abaxially, the ultimate segments (= smallest
subdivisions) often, but not always, entire; sori usually round, abaxial on the blade surfaces (usually
on veins), medial to submarginal; indusia round to kidney-shaped or obscure or absent.
AA medium-sized (4–6 genera and ca. 900–1000 species—Mabberley 1997; Nauman et al.
2000) family of terrestrial ferns. While the group is subcosmopolitan, most members are tropical.
There has been disagreement on the number of genera, with the number having ranged
from 1 to ca. 30 depending on circumscription (Smith 1993a). While members of the family
have traditionally been associated with Dryopteris (Dryopteridaceae) (e.g., Correll 1956), there
is no close relationship (Smith 1993a); the similarities are apparently due to convergent
evolution.
FAMILY RECOGNITION IN THE FIELD: sori usually on veins (but not marginal) on lower leaf surfaces;
leaves usually all alike, 1-pinnate-pinnatifid, 2-pinnate-pinnatifid, or 2–3 pinnatifid, the
lower surfaces with transparent needle-like hairs (distinguishing this family from Dryopteridaceae,
which lack such hairs), the ultimate leaf segments often (but not always) entire.
References: Smith 1990, 1993a.
1. Rachis conspicuously and irregularly winged between pinnae (wing tissue extended as obvious
lobes in some places); leaf blades � triangular in outline, ca. as wide as long, usually 7–25(–30)
cm long; indusia absent ___________________________________________________________ Phegopteris
1. Rachis not winged; leaf blades much longer than wide, often � 30 cm long; indusia present,
often conspicuous with a hand lens (but in Macrothelypteris they can be small or obscured in
mature sori).
2. Midveins of pinnae (= costae) grooved on upper (= adaxial) surface; leaf blades 1-pinnatepinnatifid;
veins of ultimate leaf segments reaching segment margins; indusia usually obvious
with a hand lens ____________________________________________________________ Thelypteris
2. Midveins of pinnae not grooved on upper surface; leaf blades mostly 2-pinnate-pinnatifid;
veins of ultimate leaf segments not reaching segment margins; indusia small (� 0.3 mm in
diam.) or obscure _________________________________________________________ Macrothelypteris
MACROTHELYPTERIS (H. Ito) Ching FALSE MAIDEN FERN
AA genus of ca. 10 species of tropical and subtropical regions in Asia, Africa, the Pacific Islands,
and Australia (Smith 1993a). It has frequently been included in a more broadly circumscribed
Thelypteris (e.g., Correll & Johnston 1970; Lellinger 1985; Hatch et al. 1990), but most
recent authors treat it at the generic level (e.g., Smith 1993a; Peck & Taylor 1995; Kartesz 1999;
Nauman et al. 2000). (Greek: macro, large, thelys, female, and pteris, fern)
REFERENCES: Holttum 1969; Leonard 1972.
Macrothelypteris torresiana (Gaudich.) Ching, (for Luis de Torres of the Marianas Islands, governor
of Guam in 1820), TORRES’ FERN, MARIANA MAIDEN FERN, FALSE MAIDEN FERN. Stems (rhizomes)
short-creeping; leaves monomorphic, evergreen; leaf blades mostly 2-pinnate-pinnatifid,
broadest at base, much longer than wide, to ca. 85 cm long; veins of ultimate leaf segments