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Botrychium
See list of 14 species in this genusBotrychium is an enigmatic genus with complexes of species that are separated on very subtle characteristics. Shapes and proportions are very important for determinations. Confounding identifications are the sporadic appearance of individuals from year to year and dwarf plants (which do not display morphologies conducive to identification). It is vitally important that collections include multiple individuals in order to capture variability in the population. Analysis of DNA sequence data shows that the subdivision of Botrychium into three genera (Botrychium, Botrypus, and Sceptridium) creates a paraphyletic Botrypus (Hauk et al. 2003). Therefore, only one genus is recognized here.
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1a. Trophophore 2- to 4-times ternately compound, mostly 5–25 cm long, usually as wide or wider than long, commonly sterile (i.e., without a sporophore) [Figs. 26,27]; leaf buds pubescent
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2a. Trophophore sessile or nearly so, thin and deciduous, borne high on the common stalk well above the ground; leaf sheath open; leaf bud only partly enclosed by sheathing base of leaf
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2b. Trophophore long-stalked, thick and evergreen, borne near the ground on the common stalk; leaf sheath closed; leaf bud completely enclosed by sheathing base of leaf
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3a. Trophophore highly lacerate-dissected into linear segments (in part)
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3b. Trophophore moderately divided into lanceolate to ovate segments
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4a. Trophophore leafules regularly dissected, divided to the tip; terminal leaflet segment equal to or slightly longer than adjacent, lateral leaf segments; trophophores green in fall and winter
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5a. Ultimate segments of trophophore rounded to obtusely pointed, entire to weakly crenulate, mostly 4–8 mm wide at maturity, plane, coriaceous
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5b. Ultimate segments of trophophore angular, dentate, mostly 2–5 mm wide at maturity, somewhat channeled and concave abaxially in life, semiherbaceous
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4b. Trophophore leafules irregularly dissected, not divided in the apical portion [Fig. 26]; terminal leaflet segment noticeably larger than adjacent, lateral leaf segments; trophophores green or bronze to purple in fall and winter
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6a. Trophophore leafules ovate, crenulate to denticulate, rounded to obtusely pointed at apex [Fig. 27]; trophophores green in fall and winter; dried roots 0.5–4 mm thick 1 cm from stem (mean=2 mm), pale gray to tan (rarely darker) and with sparse transverse circular ridges in the proximal 1–5 cm
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6b. Trophophore leafules lanceolate to trullate, denticulate to lacerate, acute to acuminate at apex [Fig. 26]; trophophores usually bronze to purple in fall and winter; dried roots 1.5–5.5 mm thick 1 cm from stem (mean=2.5 mm), dark gray-brown and with abundant transverse circular ridges in the proximal 1–5 cm (in part)
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1b. Trophophore simple or up to twice pinnately divided, mostly 2–10 cm long, often longer than wide, always accompanied by a sporophore (i.e., spore-bearing portion of leaf) [Figs. 28,29]; leaf buds glabrous
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7a. Trophophore leaflets linear to narrow-ovate, the apex obtuse to acuminate, the margins shallowly to deeply lobed; at least the tip of the trophophore reflexed in bud
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8a. Trophophore oblong to ovate, with 1 main axis, usually stalked; sporophore mainly erect in bud, only the very tip curved over
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8b. Trophophore deltate, with 3 axes, usually ± sessile; sporophore reflexed in bud
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7b. Trophophore leaflets nearly orbicular to obovate or flabellate, the apex rounded to truncate, the margins entire or distally few-lobed; trophophore and sporophore erect in bud or only the extreme tip of trophophore slightly inclined
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9a. Trophophore very slender and simple to obscurely lobed or with evident lobes, in the latter case usually with a greater distance between the first and second pairs of leaflets than between the second and third pairs of leaflets counting from the base
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10a. Lowest pair of trophophore lobes or leaflets, when present, not obviously larger than the next apical pair [Fig. 29]; lobes on well-developed plants usually square-oblong to obovate-oblong; stalk of trophophore inserted high on common stalk, usually at or above mid-height of plant [Fig. 29]; plants primarily of forested wetlands
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10b. Lowest pair of trophophore lobes or leaflets, when present, often noticeably larger and more complex than the next apical pair [Fig. 28]; lobes varying from oblong to flabellate to reniform; stalk of trophophore usually borne near base of plant (sometimes toward mid-height) [Fig. 28]; plants primarily of open areas such as fields, shores, and banks (in part)
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9b. Trophophore usually with evident lobes, the first and second pairs of leaflets separated by a similar or slightly longer distance than the second and third pairs of leaflets
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11a. Lowest pair of trophophore leaflets (or lobes in dwarf individuals) obviously larger and more complex in most plants then next apical pair; many trophophores with a characteristically broad, rounded to obstuse, terminal segment (in part)
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11b. Lowest pair of trophophore leaflets slightly, if at all, larger and more cleft or lobed than next apical pair; trophophores typically with small, narrow-flabellate terminal segments
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12a. Plants pale glaucous-green to white-green in life; lower trophophore leaflets frequently cleft into 2 unequal lobes, the upper lobe larger; sporophore 1.5–4 times as long as the trophophore
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12b. Plants in life green or yellow-green to glaucous-green or blue-green; lower trophophore leaflets entire to crenate or lobed, when lobed the lobes usually nearly equal; sporophore 0.8–2 (–2.5) times as long as trophophore
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13a. Trophophore leaflets overlapping to approximate, usually broad-flabellate; apical leaf segments greatly reduced in size and of a shape different from those of medial segments; medial leaflets 6–18 mm wide
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13b. Trophophore leaflets remote, usually cuneate to narrowly flabellate; apical leaf segments slightly reduced and more or less of similar shape as medial segments; medial leaflets 1–9 mm wide
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14a. Trophophore conspicuously stalked, the stalk often equal to or longer than the distance between the lower pairs of leaflets; trophophore leaflets entire to crenulate or, less frequently, notched, the lower ones spreading to ascending; branches of sporophore spreading to ascending, not or barely overlapping at maturity; mature sporophore with a stalk (0.5–) 1 or more times as long as the trophophore
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14b. Trophophore short-stalked, the stalk often shorter than the distance between the lower pairs of leaflets; trophophore leaflets entire to dentate or symmetrically lobed, the lower ones ascending; branches of sporophore ascending to erect (rarely spreading), somewhat to strongly overlapping at maturity; mature sporophore subsessile or short-stalked, the stalk usually shorter than the length of the trophophore
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15a. Stalk of sporophore usually 0.25–0.5 (–1) times as long as the trophophore; trophophore green to bright yellow-green in life, not clasping to loosely clasping the sporophore at maturity, with narrow-cuneate to oblong leaflets, the lowest pair sometimes with sporangia; rachis of trophophore relatively narrow, up to 0.25 times as wide as the entire trophophore; plants moderately short, commonly 10–15 cm tall, without spherical gemmae at the root bases
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15b. Stalk of sporophore less than 0.25 times as long as the trophophore; trophophore pale green to glaucous-green in life, loosely to tightly clasping the sporophore at maturity, with linear to narrow-cuneate segments, the lowest pair almost never with sporangia; rachis of trophophore often relatively broad, up to 0.35 times as wide as the entire trophophore; plants very short and compact, rarely taller than 6 cm, sometimes with minute, spherical gemmae at the root bases
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Each photo represents one species in this genus.