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Polystichum resources
Polystichum of South AfricaPolystichum of South Africa
inoperativeUnited States (link inoperative)
Flora of AustraliaFlora of Australia
Flora of North AmericaFlora of North America
inoperativeThe Polystichum Website (link inoperative)
inoperativecross section: rachis, 5 vascular bundles (link inoperative)
with authorities and references; also world distribution mapswith authorities and references; also world distribution maps
Integrated Taxonomic Information SystemIntegrated Taxonomic Information System
Major evolutionary events Major evolutionary events
Systematics of Polystichum in Western North America North of MexicoSystematics of Polystichum in Western North America North of Mexico

All Ferns
     acrostichoides  aculeatum
     andersonii  braunii
     craspedosorum  imbricans
     kruckebergii  lemmonii
     lepidocaulon  lonchitis
     makinoi  munitum
     neolobatum  polyblepharum
     proliferum  retroso-paleaceum
     rigens  scopulinum
     setiferum  setigerum
     tagawanum  tripteron
     tsus-simense  xiphophyllum

 Other Genera
    Adiantum  Arachniodes
    Aspidotis  Asplenium
    Astrolepis  Athyrium
    Blechnum  Cheilanthes
    Cryptogramma  Cyrtomium
    Cystopteris  Dennstaedtia
    Deparia  Diplazium
    Dryopteris  Gymnocarpium
    Lygodium  Matteuccia
    Onoclea  Oreopteris
    Osmunda  Pellaea
    Phegopteris  Pleopeltis
    Polypodium  Pteridium
    Pteris  Pyrrosia
    Thelypteris  Woodsia
Polystichum Roth (Dryopteridaceae) Earlier placement: Aspideaceae

Shield fern

Etymology Polystichum is from the Greek polys, many, + stichos, row. The sori are in many rows.
Description Rhizome: erect, scales.
Frond: evergreen, monomorphic or weakly dimorphic.
Stipe: scaly, vascular bundles: 4 or more, in an arc.
Blade: 1-3 pinnate, lanceolate; at emergence the croziers droop backwards, glossy, linear to lanceolate scales below, no hairs.
Pinnae: usually an upper side lobe, costae grooved above, grooves discontinuous from rachis to costae, segments spinulose, veins free, forked, anadromic.
Sori: round, in 1 (2) rows between midrib and margin, indusium: peltate or rarely absent, central, sporangia: yellow or brownish to black.
Distinctive Characteristics similar to Dryopteris, but distinguished by the upward ear on the pinnae, commonly spiny margins, the peltate indusia, and discontinuous grooving between rachis and costa. It also has many characteristics in common with Cyrtomium, but the latter has netted veins; here they are always free, perhaps forked.
Polystichum . The indusium attached at the center (peltate) is characteristic of the genus.  Illustration from Scandinavian Ferns by Benjamin Ĝllgaard and Kirsten Tind, Rhodos, 1993.
Polystichum croziers
When Polystichum fronds unfurl, the bend-over-backwards tassel-like form is characteristic of the genus. Not every specimen shows it, however.  Photo - Tom Stuart
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