Mountain holly fern (Polystichum scopulinum) COSEWIC assessment and status report: chapter 3

Species Information

Name and classification

Scientific name:

Polystichum scopulinum (D.C. Eaton) MaxonFootnote1

Synonym:

Polystichum mohrioides (Bory) Presl var. scopulinum (D.C. Eaton) Fern.

Common names:

Mountain Holly Fern or Polystic des Rochers

Family:

Dryopteridaceae (Wood Fern Family)

Major plant group:

ferns

Description

Mountain holly fern, P. scopulinum (D.C. Eaton) Maxon, is a member of a cosmopolitan genus of over 175 species (Wagner 1993; Smith and Lemieux 1993). It is one of eight Polystichum species occurring in British Columbia (Ceska 2000; Douglas et al. 2002a), four occurring in Quebec (Wagner 1993), and three on the island of Newfoundland (Meades et al. 2000). Nine Polystichum species are found in Canada (Cody and Britton 1989; Wagner 1993). 

Polystichum scopulinum is an evergreen, perennial, tufted fern arising from a short, stout rhizome (Figure 1; Ceska 2000). The ascending fronds are 10-40 cm long, 3-7 cm wide and 1-pinnate. The 20-40 pinnae on each side of the rachis are oblong with acute pinnules and have ultimate segments that are minutely, spiny-toothed. The round sori are attached near the mid-vein with entire or fringed indusia.

In British Columbia, P.scopulinum may be confused with either P. lemmonii Underw. or P. kruckebergii W.H. Wagner. It may be distinguished from P. lemmonii by the presence of spines on the teeth of the ultimate segments of its pinnae (Hitchcock et al. 1969; Wagner 1993; Ceska 2000). It differs from P. kruckebergii in having pinnae that are obtuse at the tips (especially at the base of the fronds) and armed with fine, incurved teeth, whereas P. kruckebergii has pinnae that are abruptly pointed at the tips (especially at the base of the fronds) and armed with coarse, spreading teeth (Hitchcock et al. 1969; Wagner 1993; Ceska 2000). Prior to the work of Wagner (1966), who recognized and named P. kruckebergii, all material of the latter in British Columbia was identified as P. scopulinum (e.g., Taylor 1963, 1970).  

The four species in Quebec and three on the island of Newfoundland are all readily distinguishable on the basis of their leaf morphology (see Gleason 1963).

Figure 1. Illustration of Polystichum scopulinum: plant growth habit with enlarged leaf and leaflets (leaflets x 0.5) with one showing the underside with clusters of sori (top left); enlarged sorus with sporangia surrounding the central flap of protective tissue, the indusium (top right, x 15). Line drawing from Hitchcock et al. (1969) by permission.

Figure 1.  Illustration of Polystichum scopulinum: plant growth habit with enlarged leaf and leaflets (leaflets x 0.5) with one showing the underside with clusters of sori (top left); enlarged sorus with sporangia surrounding the central flap of protective tissue, the indusium (top right, x 15). Line drawing from Hitchcock et al. (1969) by permission.

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