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Pumice moonwort (''Botrychium pumicola'') is a rare fern of southern Oregon and the Modoc Plateau in northern California.〔List of plants on the Modoc National Forest〕 It pertains to the adder's-tongue family (Ophioglossaceae) which may be closely related to the whisk ferns (Psilotaceae). These two families together, according to recent research, share a common ancestor which appears to have diverged early on from the rest of the fern lineage; this probably explains the distinctive morphologies of the members of these two families. There has been speculation that ''B. pumicola'' is merely a variety of ''B. simplex''. The two species are indeed closely related, with ''B. montanum'' also somewhat closely related, but it has been determined that ''B. pumicola'' is in fact a separate species.〔 〕 The plant is mycorrhizal, and grows sporophytic gemmae (''i.e.'', little structures for the asexual reproduction of the sporophytic, or diploid, phase of the plant's life cycle). Camacho〔 〕 believes that the gemmae might be adaptations to a dry climate. Another name for plants of this genus is 'grapeferns,' since the sexual reproductive structures (synangia) look like tiny yellow-green grapes. == Description == The plant is stout, with a very congested appearance, fleshy, 8–22 cm (3–9 in) high. Leaves appear in summer. Roots are abundant, 1 mm (0.004 in) or less in diameter. The rhizome is erect, stout, elongate (2–8 cm, 1-3 in, long and 3 mm, 0.1 in, in diameter). Fronds are one or sometimes two, erect, 6–14 cm, 2-5½ in, long, the common stalk hypogean, 4–9 cm, 1½-3½ in, long and 2-3½ mm, 0.08-0.14 in, in diameter, thickly sheathed with the stems of old fronds. Trophophore is sessile or nearly so; stalk 0–10 mm, 0-0.4 in, a tenth to a half the length of trophophore rachis; blade is dull, strongly glaucous, whitish green, deltate (triangular), thickly leathery, twice pinnate, with apex bent down in vernation, 2–4 cm, 1-1½ in, long and 1½-4 cm, ½-1½ in, broad; ternate, the middle division the largest, broadly oblong to rounded-deltoid, the lateral ones similar or rhombic-oblong, all pinnately parted; pinnae closely imbricate (overlapping), up to 6 pairs, strongly ascending, sublunate to flabelliform, broadly crenate to incised, or the larger ones radially cleft into cuneiform lobes; distance between 1st and 2nd pinnae not or slightly more than between the 2nd and 3rd pairs, asymmetrically cuneate; basal pinna pair often divided into 2 unequal parts, lobed to tip, margins entire, sinuate to shallowly crenate, apex rounded to truncate, venation pinnate. The trophophore is located high on the common stalk, but the common stalk is subterranean, giving the impression that the leaf originates near ground level. Sporophore is once to thrice pinnate, with the tip recurved in vernation, sessile or short-stalked, equalling or surpassing (1 to 1½ times) the sterile blade, but with the stalk shorter than the trophophore; extremely compact sporangial cluster.〔 〕〔 〕〔 〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Botrychium pumicola」の詳細全文を読む スポンサード リンク
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