Cystopteridaceae |
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Plants terrestrial; roots blackish, wiry, inserted radially, non-proliferous; rhizomes epigeous or more often subterranean, short- to more often long-creeping, occasionally suberect (Cystopteris), commonly branched, bearing scales and sometimes golden hairs similar to the root-hairs (e.g., C. protrusa (Weath.) Blasdell); rhizome scales lanceolate, clathrate or non-clathrate, the margins glandular or not, without distinct pubescence, entire to ciliate, the teeth when present not formed by two adjacent cells; leaves green and not covered in mucilage during any stage of development, spirally arranged, monomorphic, bulbiferous in a few Cystopteris, closely spaced to distant, bearing scales and sometimes gland-tipped hairs, the scales sometimes reduced to filiform proscales (Cystopteris) or catenate hairs (Acystopteris); petioles stramineous throughout or proximally darkened, the base narrow, or conspicuously thickened and then starch-filled and persistent (trophopods), without conspicuous aerophores, without a proximal articulation, sometimes with golden hairs similar to the root hairs (e.g., Cystopteris moupinensis Franch.); petiolar vascular bundles two, the bundles with hippocampiform-shaped xylem, distally uniting to form a single V-shaped bundle; laminae thin-herbaceous, 2–3-pinnate-pinnatifid (pinnate-pinnatifid in Cystoathyrium), broadest at the base or lanceolate, the apex non-conform, the leaf marginal cells differentiated into nodulose hyaline cells (Acystopteris, Cystopteris) or not (Gymnocarpium); pinna axes distinctly articulate in Gymnocarpium, otherwise non-articulate, sulcate adaxially, lacking a free central ridge; the rachis grooves continuous or not, the sulcus wall of the rachis continuing as a prominent ridge onto the sulcus wall of the costa or not; veins free, terminating at the leaf margin, the vein endings not differentiated; sori dorsal along veins, not terminal, round or slightly elongate (Gymnocarpium), indusiate (Acystopteris, Cystoathyrium, Cystopteris) or exindusiate (Gymnocarpium); soral receptacle distinctly raised and hardened (Acystopteris, Cystopteris) or flat (Gymnocarpium); indusia basal (Acystopteris, Cystoathyrium, Cystopteris); sporangia with stalks two or three cells wide in the middle; spores monolete, non-chlorophyllous, tan (Acystopteris) or brown, the perispore echinate, tuberculate, or with broad folds, the folds sometimes perforate; chromosome base number x = 40. The Cystopteridaceae is a family of five genera and about 30 species. Although the genera are distinctive, Cystopteridaceae as a whole are not easily characterized. Among families with petioles that contain two vascular bundles, they can be distinguished by an absent or hood-like indusium, usually long-creeping and subterranean rhizome, and veins that terminate at the leaf margin. Cystopteridaceae are unusual in their primarily temperate distribution and tendency to occupy montane habitats. Global distribution of Cystopteridaceae. CAUTION: GBIF records include introduced and cultivated plants. In addition, GBIF may follow a different taxonomic interpretation from that adopted in the treatments presented here. For all three reasons, the distribution shown may differ from statements presented here about a taxon's native distribution.
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