(rusty woodsia)
Select an option below for more information on this species
Photo of Woodsia ilvensis by Carl Roland
|
Rusty woodsia is a small fern (although our largest
Woodsia species), with red-brown scales and coarse hairs along the stem. It occurs in rocky slopes and outcrops from the lowlands to the alpine zone. The fronds are 3-20 cm tall,
lanceolate or
elliptic in outline. The fronds are 2-3
pinnate-
pinnatifid (more divided than other woodsia species). The base of the stem is dark brown or purplish.
Pinnae are longer than they are wide,
ovate or triangular, tapering at the ends. There are light brown
sori on the backs of the leaves near the margins, surrounded by hairs. The very scaly stems and
pinnae twice as long as they are wide distinguish it from other woodsia species in the park. The similarly narrow, alpine
Dryopteris fragrans has horseshoe-shaped
indusia covering the
sori.
Rusty woodsia is perennial and
deciduous. The timing of spore production and establishment in
Woodsia ilvensis is unknown.
Like all ferns, rusty woodsia is spore producing. Spores germinate in suitably moist habitats into haploid
gametophytes, tiny heart-shaped plants. If fertilized,
gametophytes sprout new fern plants.
Rusty woodsia is a circumpolar species with a boreal-montane distribution. In North America, this species occurs from Alaska to southeastern B.C. in the West. This species has an eastern disjunction from Nunavut the Great Lakes, and occurs southward to Virginia. The species also occurs in eastward to Greenland and Europe, where it is highly endangered in Britain. Rusty woodsia is widespread in Alaska, although infrequent, occurring from the northern edge of the Brooks Range across the mainland to the Alaska Peninsula and in southeast Alaska. Woodsia ilvensis occurs in occasional sites on both sides of the Alaska Range in Denali.
Details are shown in the Plots & Charts found at right, depicting recent Denali data.
This species is most likely to be found on extremely steep slopes (>28 degrees). Its elevational range in Denali is 275 to 1505 m. It is more common on southern aspects than on northern.
Details are shown in the Plots & Charts found at right. For more on how to interpret these figures, visit Understanding Data Presented.
Rusty woodsia is found on rock outcrops, slopes as well as forested sandy or rocky slopes. The soil pH of this species sites is acidic to neutral (
Dyer et al. 2001).
Dry slopes and rocky sites.
