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

DRYOPTERIS/DRYOPTERIDACEAE 347
Carr 2002d; Poole et al. 2002), because of its limited distribution in the state, we consider this
species to be of conservation concern in TX. �
DRYOPTERIS Adans. WOOD FERN, SHIELD FERN
Plants terrestrial or on logs; rhizomes scaly; leaves 1-pinnate-pinnatifid, monomorphic to
slightly dimorphic, the fertile leaves sometimes larger than the sterile leaves, the sterile leaves �
evergreen; pinnae with serrate segments; sori round, in a single row on each side of the midvein
of the fertile segments, midway between midvein and margin; indusia round-reniform, attached
at a narrow sinus.
AA widely scattered but largely north temperate genus of ca. 250 species (Montgomery &
Wagner 1993). A few occur in North America, but most are found in temperate Asia. Hybridization
between species is common (Wagner 1970; Montgomery & Wagner 1993). The genus is
widely cultivated in temperate gardens (Hoshizaki & Moran 2001). The n temperate D. filixmas
(L.) Schott, MALE FERN, is one of the oldest vermifuges (= a medicine that expels intestinal
worms) known—it paralyzes tapeworms (which can then be removed) but is dangerous because
it also paralyzes voluntary muscles of patients (Mabberley 1997). (Greek: drys, oak or tree,
and pteris, fern; several species are associated with oak woodlands)
REFERENCES: Walker 1962; Wagner 1970; Thomas et al. 1973; Montgomery & Paulton 1981; Carlson
& Wagner 1982; Montgomery 1982; Peck & Peck 1988; Fraser-Jenkins 1986; Werth et al.
1988; Montgomery & Wagner 1993; Hoshizaki & Wilson 1999; Peck 2000.
1. Segments of fertile pinnae nearly the same width as those of typical sterile pinnae, occupying
distal 1/2 to nearly entire blade; teeth along segments of pinnae narrowed to a minute spinelike
tip, often incurved (toward margin); species of extreme ne part of East TX ____________________ D. celsa
1. Segments of fertile pinnae distinctly narrower than those of typical sterile pinnae, occupying
distal 1/3 to at most distal 1/2 of blade; teeth along segments of pinnae triangular, not incurved;
species of se part of East TX ______________________________________________________ D. ludoviciana
Dryopteris celsa (W. Palmer) Knowlton, W. Palmer & Pollard, (held high, elevated), LOG FERN.
Stems (rhizomes) short-creeping; petioles scaly at least at base; leaves � evergreen; leaf blades 1pinnate-pinnatifid,
ovate-lanceolate, 22–80 cm long, the basal pinnae reduced; fertile pinnae in
distal 1/2 of leaf blade to nearly the entire blade; segments of fertile pinnae nearly the same
width as those of typical sterile pinnae, not more widely spaced. Rotting logs and piles of humus
in swamps or seeps, acidic soils; included based on a 1925 Palmer collection (29404, MO,
GH—Peck & Peck 1988) from Bowie Co. (cited in Correll 1956 and Correll & Johnston 1970 as D.
cristata) in the extreme ne corner of e TX and the range map in Werth et al. (1988) showing ne
TX; e U.S. from NY s to SC w to AR, MO, and TX, also MI. Dryopteris cristata (L.) A. Gray,
CRESTED WOOD FERN, a circumboreal species of the ne U.S. and s Canada, was erroneously reported
for TX (Correll 1956; Correll & Johnston 1970), but does not occur in the state (Thomas
et al. 1973; Peck & Peck 1988; Peck 2000). Sporulating summer–fall. [D. goldiana (Hook. ex
Goldie) A. Gray subsp. celsa W. Palmer] Dryopteris celsa is a fertile allotetraploid resulting from
hybridization between D. goldiana (Hook. ex Goldie) A. Gray and D. ludoviciana (Walker 1962;
Montgomery & Wagner 1993). It has been proposed that the two parent species, which no
longer occur together, were pushed into contact by the climatic change accompanying glaciation
(Taylor 1984). In various parts of its range, D. celsa is known to hybridize with six other
species. The common name, LOG FERN, is derived from the tendency of the species to grow on
logs or humus (Snyder & Bruce 1986). While not officially designated as such (e.g., TOES 1993;
Carr 2002d; Poole et al. 2002), because of its limited distribution in the state, we consider this
species to be of conservation concern in TX. �
Dryopteris ludoviciana (Kunze) Small, (of Louisiana, where the species was first discovered),
SOUTHERN WOOD FERN, LOUISIANA WOOD FERN. Stems (rhizomes) short-creeping, stout; petioles