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1 Stem obviously jointed; leaves scale-like, borne in a whorl at each of the distant joints; spores borne in a terminal strobilus with peltate scales |
1 Stem (or rhizome) not jointed; leaves scale-like or larger, but if scale-like not borne in whorls at distant joints; spores borne variously, but if in a terminal strobilus the scales not peltate. |
..2 Leaves linear, grass-like, 1-60 cm long, 20× or more as long as wide. |
....3 Leaves solitary (though often the internodes very short from a thin, creeping rhizome); sporangia borne in a spherical (ca. 3 mm in diameter) sporocarp on a separate branch from the rhizome |
....3 Leaves numerous from a corm or short-creeping rhizome; sporangia either borne in the expanded leaf bases ( Isoetes in ISOETACEAE) or in 2 rows at the tip of the linear fertile leaves ( Schizaea in SCHIZAEACEAE), or in a sub-marginal groove on either side of the midrib ( Vittaria in PTERIDACEAE). |
......4 Leaves straight and stiff, arching, or flaccid, from a 2-3-lobed corm; sporangia borne in the expanded, hyaline leaf bases |
......4 Leaves either straight and stiff or notably spiral-curly, from a short-creeping rhizome; sporangia borne in 2 rows either at the expanded pectinate tip of the fertile leaves or along much of the length of the linear leaves. |
........5 Leaves 10-60 cm long, straight, stiff; plants epiphytic or rarely epipetric, the leaves pendent |
........5 Leaves 1-12 cm long, spiral-curly; plants terrestrial in peaty substrate, the leaves erect |
..2 Leaves various (scale-like, awl-like, moss-like, or flat), but not linear and grass-like, mostly 1-10 (-20)× as long as wide. |
..........6 Leaves inconspicuous, reduced to a few nerveless scales (< 1.5 mm long), the internodes much longer than the leaves; sporangia yellowish, 3-locular, 1-2 mm in diameter; stems upright, repeatedly branched dichotomously |
..........6 Leaves either larger or, if scale-like, with 1 or more nerves and longer than the internodes (the leaves thus overlapping); sporangia yellowish to brownish, 1-locular, < 1 mm in diameter; stems either subterranean or surficial rhizomes or erect or ascending (and sometimes dichotomously branched in whole or in part in Huperzia in HUPERZIACEAE, and Diphasiastrum and Dendrolycopodium in LYCOPODIACEAE). |
............ 7 Plant with leaves very numerous and overlapping along the creeping, ascending, erect, or pendant stems, the leaves scale-like or awl-like, 0.5-2 (-3) mm wide, typically acute, acuminate, or hair-tipped; sporangia either in terminal strobili (axillary to specialized, smaller leaves) or axillary to normal leaves; [Lycophytes]. |
............ ..8 Sporangia borne in flattened or quadrangular strobili sessile at the tips of leafy branches; spores and sporangia each of two sizes, the megasporangia larger and borne basally in the strobili |
............ ..8 Sporangia borne either in the axils of normal foliage leaves, or in strobili sessile at the tips of leafy branches or stalked on specialized branches with fewer and smaller leaves; spores and sporangia each of one size. |
............ ....9 Leafy stems erect or pendant, simple or dichotomously branched, the ultimate branches vertically oriented (upwards or downwards); sporophylls like the sterile leaves or only slightly reduced, in annual bands along the stem; vegetative reproduction by leafy gemmae near the stem apex ( Huperzia) or lacking gemmae ( Phlegmariurus) |
............ ....9 Leafy stems prostrate or erect, if erect then generally branched, the ultimate branches spreading (horizontal) or ascending; sporophylls differing from sterile leaves, either broader and shorter, or more spreading, aggregated into terminal cones; lacking vegetative reproduction by gemmae. |
............ 7 Plant with leaves not as above (see below for details); [Pteridophytes]. |
............ ......10 Leaves palmately lobed. |
............ ........11 Leaves divided into separate sterile and fertile segments, the sterile leaf blade 30-90 cm long, ovate to lanceolate, entire-margined, obtuse, the longer fertile portion with 2 rows of sporangia somewhat imbedded in it |
............ ........11 Leaves with fertile portions in patches near the tips of the lobes |
............ ......10 Leaves unlobed (or if lobed, pinnately so). |
............ ..........12 Plant with 1 (-several) leaves, divided into separate sterile and fertile segments, the sterile leaf blade 0.3-90 cm long, ovate to lanceolate, entire-margined, unlobed, obtuse, the longer fertile portion with 2 rows of sporangia somewhat imbedded in it |
............ ..........12 Plant with many leaves, generally 5 or more, not divided into separate sterile and fertile segments, the leaves either (a) small, 0.3-1.6 cm long, obovate, scattered along a very thin creeping rhizome, or (b) larger, (2-) 8-30 cm long, cordate at base, the tip long-attenuate (often proliferous, bearing a plantlet at the tip). |
............ ............ 13 Leaf blades (2-) 8-30 cm long, cordate at the base, the tip long-attenuate, often proliferous (bearing a plantlet at the tip); sporangia grouped into indusiate sori on the undersurface; leaf texture moderately thick; rhizome erect or ascending, 1.0-1.5 mm in diameter, the leaves clustered from its tip |
............ ............ 13 Leaf blades 0.3-15 cm long, cuneate at the base, acute to rounded or obtuse at the tip, not proliferous; sporangia solitary in a marginal pocket on the leaf; leaf texture very thin; rhizome creeping on the surface of rock or bark, either 0.1-0.3 or 0.5-1.5 mm in diameter, the leaves scattered along it |
............ ............ ..14 Leaf blades 0.3-1.6 cm long; sporangia solitary in a marginal pocket on the leaves; leaf texture very thin; rhizome 0.1-0.3 mm in diameter |
............ ............ ..14 Leaf blades 2-15 cm long; sporangia borne in round sori on the lower surface of the leaves; leaf texture herbaceous to subcoriaceous; rhizome 0.5-1.5 mm in diameter |
1 Leaves pinnatifid or bipinnatifid, the pinnae not fully divided from one another (the rachis winged by leaf tissue most or all of its length). |
..2 Leaves pinnatifid, the pinnae not lobed. |
....3 Leaf blades with a long-attenuate apex, blade lobed for up to 2/3 its length; sori elongate |
....3 Leaves without a long-attenuate apex, blade lobed for > 4/5 of its length; sori round |
..2 Leaves bipinnatifid, at least the lowermost pinnae deeply lobed. |
......4 Leaves of a very delicate texture, 1 cell thick; sori borne in cups on the leaf margins; [rock outcrops with high air humidity] |
......4 Leaves of an herbaceous, subcoriaceous, or coriaceous texture, > 1 cell thick; sori otherwise; [various habitats, not strictly of moist sites]. |
........5 Leaf blades 1-7 cm long, hairy with some hairs > 1 mm long |
........5 Leaf blades > 7 cm long, glabrescent or hairy with hairs < 1 mm long. |
..........6 Lowermost (and other) pinnae with numerous, rather even lobes |
..........6 Lowermost pinnae with a few, irregular lobes (the upper pinnae unlobed) |
1 Leaves pinnate, pinnate-pinnatifid, 2-pinnate, or even more divided, to 5-pinnate (the rachis naked for most of its length, often winged in the apical portion). |
............ 7 Leaves pinnate or pinnate-pinnatifid. |
............ ..8 Leaves of a very delicate texture, 1 cell thick; sori borne in cups on the leaf margins; [rock outcrops with high air humidity] |
............ ..8 Leaves of an herbaceous, subcoriaceous, or coriaceous texture, > 1 cell thick; sori otherwise or sporangia not grouped in sori; [various habitats, not strictly of moist sites]. |
............ ....9 Pinnae > 1 cm wide; leaves subcoriaceous to coriaceous |
............ ......10 Sporangia borne on 2 specialized fertile pinnae (in rows on segments of the 2 basalmost fertile pinnae of the leaf); [native; TX westwards] |
............ ......10 Sporangia borne on the lower surface of green leaves; [collectively widespread] |
............ ........11 Veins free; [native; s. FL] |
............ ........11 Veins anastamosing (rejoining one another) to form a netlike pattern of areoles. |
............ ..........12 Costae with a groove on the upper side, sometimes with tan, filiform scales; margins of segments denticulate, crenate, or spinulose |
............ ..........12 Costae rounded or flat on the upper side, with red, multicellular hairs; margins of segments entire or with rounded lobes |
............ ....9 Pinnae < 1 cm wide; leaves herbaceous to subcoriaceous. |
............ ............ 13 Sori on the undersurface of the leaf, located away from the margins |
............ ............ 13 Sori on the undersurface of the leaf, marginal and more-or-less hidden beneath either the unmodified revolute leaf margin or under a modified, reflexed false indusium |
............ 7 Leaves bipinnate or more divided. |
............ ............ ..14 Leaf blade pentagonal, broadly triangular, or narrowly triangular in outline, ca. 1-2.5× as long as wide. |
............ ............ ....15 Leaf blade narrowly triangular in outline, mostly 2-2.5× as long as wide. |
............ ............ ......16 Sporangia borne either in many sori on fertile blades or on fertile pinnules borne at the base of the otherwise sterile blades |
............ ............ ......16 Sporangia borne in a solitary sorus terminal on the truncate apex of wedge-shaped leaf segments |
............ ............ ....15 Leaf blade either ovate, pentagonal, or broadly triangular in outline, mostly 0.8-2× as long as wide. |
............ ............ ........17 Leaves dimorphic, fertile leaves with longer and narrower segments than the sterile leaves |
............ ............ ........17 Leaves monomorphic. |
............ ............ ..........18 Leaf segments strongly revolute; sporangia scattered along veins or submarginal, not grouped into indusiate sori; lower surface of leaf segments either densely covered with a whitish farina or distinctly bluish-green |
............ ............ ..........18 Leaf segments planar; sporangia borne in round, indusiate sori; lower surfaces of leaf segments green. |
............ ............ ............ 19 Leaf blade pentagonal in outline, the terminal pinna by far the largest; rhizome 5-8 mm in diameter; indusia present, thick, persistent, and reniform; [introduced species, rarely naturalized] |
............ ............ ............ 19 Leaf blade broadly triangular in outline, the basal pinnae by far the largest; rhizome ca. 1 mm in diameter; indusia absent; [native species of mountain peaks from n. NC and VA northwards] |
............ ............ ..14 Leaf blade elongate, mostly lanceolate, generally > 4× as long as wide (except in Adiantum, with leaf blade often only 1.5-3× as long as wide, but not notably triangular or pentagonal in outline). |
............ ............ ............ ..20 Sori marginal, usually more-or-less hidden under the revolute margin of the pinnule |
............ ............ ............ ..20 Sori not marginal, either exposed, or slightly to strongly hidden by indusia. |
............ ............ ............ ....21 Leaf blades 3-12 cm long; sori elongate, covered by a flap-like, entire indusium |
............ ............ ............ ....21 Leaf blades 4-30 (-50) cm long; sori globular, surrounded or covered by an entire, ciliate, or divided indusium. |
............ ............ ............ ......22 Veins reaching the margin; indusium attached under one side of the sorus, hood-like or pocket-like, arching over the sorus; petioles glabrous or sparsely beset with scales, the petiole bases not persistent |
............ ............ ............ ......22 Veins ending short of the margin; indusium attached under the sorus, either cup-like (divided into 3-6 lanceolate to ovate lobes which surround the sorus from below) or of minute numerous septate hairs, which extend out from under the sorus on all sides; petioles often densely beset with scales, the petiole bases persistent |