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

SALVINIACEAE
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fern, derived from pteron, wing or feather, in reference to the closely spaced pinnae which give
the leaves a somewhat feather-like appearance—Nauman 1993b).
REFERENCES: Nauman 1993b; Stanford & Diggs 1998.
Pteris multifida Poir., (much divided, in reference to the leaves), HUGUENOT FERN, SPIDER BRAKE,
SPIDER FERN, CHINESE BRAKE, SAW-LEAVED BRACKEN. Stems (rhizomes) short-creeping, densely
scaly; leaves evergreen, monomorphic, clustered, (10–)25–60 cm long; leaf blades 10–35 cm long,
10–25 cm wide, essentially glabrous, at least partially 2-pinnatifid; pinnae opposite, 3–7 pairs,
lanceolate to linear, those in at least distal 1/2 of mature leaves decurrent on the conspicuously
winged rachis (rachis wing constricted distal to each pair of pinnae); basal and sometimes the
medial pinnae with 1–2 lobes or pinnules (at least some pinnae are deeply palmately 3-divided,
except on the leaves of young plants, which can have palmately compound leaves with three
unlobed pinnae), the distal pinnae simple; sterile pinnae wider than fertile pinnae, with margins
serrulate to serrate; fertile pinnae entire to serrate near apex; sori near margins of fertile
pinnae or pinnules, usually � continuous, the pinna or pinnule margins reflexed over sori to
form false indusia. Masonry of old brick buildings, calcareous sandstone talus blocks, and
sandy soils of woods; Fayette (BRIT), Hardin (TAES), Jefferson, and Montgomery (Turner et al.
2003) cos.; naturalized se U.S. from MD s to FL w to AR and TX, also CA, IL, IN, KY, and NY.
Sporulating Jun–Dec. Native of e Asia. [Pycnodoria multifida (Poir.) Small] According to Correll
(1956), this species “… was cultivated on many of the older plantations in the Deep South where
it still persists. It has escaped in many areas into the nearby woods and can now be found some
miles from its original point of cultivation. It is so completely at home in some places in east
Texas that it must be considered as naturalized.” According to Nelson (2000), P. multifida “was
first discovered in the U.S. in 1868 in a Huguenot cemetery in Charleston, South Carolina; hence,
one of its common names, Huguenot fern. The common name ‘spider brake’ is likely in reference
to the spiderlike appearance of the deeply-divided leaves.” I
Pteris vittata L., LADDER BRAKE, CHINESE BRAKE, CHINESE LADDER BRAKE, (longitudinally
striped—in reference to the linear false indusium), an Asian native well known as an escape
from cultivation in coastal areas of the southeastern United States, is commonly found on exposed
limestone (e.g., pinelands) and on a variety of man-made calcareous substrates (e.g., sidewalks,
buildings, old masonry) (Nauman 1993b). It is known from LA (Kartesz 1999) and and is
known from the Edwards Plateau of Texas (Stanford & Diggs 1998) based on a collection from a
stream-side limestone boulder in San Saba Co. (J.W. Stanford 5308, 1987, BRIT, HPC, SPLT). It
should be watched for in East TX; naturalized in se U.S. from SC s to FL w to TX, also CA. The
strictly 1-pinnate leaves (the pinnae without lobes or divisions) easily distinguish this species
from P. multifida. Note that because of its 1-pinnate leaves, this species, presently unknown
from East TX, will not key properly in the key to genera above. I
SALVINIACEAE T. Lestib.
FLOATING FERN OR WATER-SPANGLE FAMILY
AA very small family (1 genus, ca. 10 species) of heterosporous (= with 2 spore types) aquatic
ferns found mostly in the tropics, but ranging from s U.S., Mexico, West Indies, Central America,
and South America to Eurasia and Africa, including Madagascar (Nauman 1993d). The
Azollaceae has often been included in the Salviniaceae, but according to Lumpkin (1993), the
relationship is not close enough to warrant inclusion in the same family. However, molecular
evidence does indicate that Salvinia and Azolla are each other’s closest living relative (Hasebe
et al. 1995), and the two families are probably appropriately treated in the same order (Schneller
1990b). Three families of heterosporous water ferns occur in East TX (Azollaceae—Azolla,