Meekly named, the deer fern, or, hard fern (Blechnum spicant syn. Struthiopteris spicant) nevertheless sports fantastical foliage in the spring and summer months. A key identifying feature is its dimorphic fronds. Each year, a mature deer fern produces two types of fronds: a spreading rosette of flat, leathery fronds that are sterile but form a wide surface area for photosynthesis, and delicate, much taller fertile fronds with thread-like leaflets that produce spores and then disappear. The fiddleheads of the fertile fronds are especially dragon-like as they uncoil and, when fully extended, resemble airy avian plumes. Furthermore, the somewhat translucent young fronds of both types are stunning when catching sunlight dappled across the shadowy forest floor.
Deer ferns establish large clumps of fronds that grow from woody rhizomes.1Rhizomes are thickened stems that grow along or under the soil surface and bear shoots above and roots below. The tough sterile fronds are evergreen, even when flattened beneath the winter snowpack at higher elevations. The fiddleheads of the fertile fronds are often hairy and tinged with a shiny, chestnut red that contrasts with the bright chartreuse of the plant’s other spring growth. The fertile fronds stand upright at the center of each clump, typically reaching up to three feet/one meter in height, with the spreading sterile fronds usually about half that length. Unlike the sterile fronds, the fertile fronds are deciduous and wither away by autumn. Both types of fronds bear single pinnate2A leaf is pinnate when it bears leaflets on opposite sides of a central stem. A leaf is simple pinnate when each leaflet is not further subdivided. leaflets, arranged closely on the sterile fronds and widely on the fertile fronds. The leaflets are widest at the center of each frond, further adding to their feather-like appearance.
The deer fern has an incredibly wide distribution, ranging from Europe and North Africa through Asia and into western North America from Alaska down to central California. Although it generally inhabits the coastal hinterlands up to mid elevations throughout its range, the deer fern also occurs in small inland enclaves in the Rocky Mountains of British Columbia, Idaho, and Montana and the Sierra Nevada of California. It prefers shady conifer forest, where it is a climax understory species in mature stands. In Western Washington, it is typically found in moist woodlands, but tolerates both wet and dry conditions across its range.
Although classified within the broader Blechnaceae family, the deer fern’s placement in either of the Blechnum or Struthiopteris genera appears unsettled, rendering both of its botanical names acceptable synonyms.
Note the deer ferns on the lower left and extreme lower right of this photo of typical Western Washington old-growth forest habitat:
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