Polystichum lemmonii
Polystichum acrostichoides
Lemmon's holly fern, Lemmon's sword fern, Shasta fern, Shasta sword fern
Christmas fern, polystic faux-acrostic
decumbent to ascending.
erect.
erect, 1–3.5 dm;
bulblets absent.
dimorphic (only in this species);
fertile pinnae distal, much contracted;
sterile leaves arching, 3–8 dm;
bulblets absent.
1/5–1/4 length of leaf, sparsely scaly;
scales pale tan, abruptly diminishing in size distally.
1/4–1/3 length of leaf, densely scaly;
scales light brown, diminishing in size distally.
narrowly lanceolate, 2-pinnate, scarcely narrowed at base.
linear-lanceolate, 1-pinnate;
base narrowed.
ovate, overlapping, folded inward and twisted horizontally, 0.5–2 cm;
base truncate to oblique, proximal acroscopic pinnules not enlarged;
apex broadly acute;
microscales narrowly lanceolate, with few projections, sparse, ± confined to costa of both surfaces.
oblong to falcate, not overlapping, in 1 plane, 2–6 cm;
base oblique, acroscopic auricles well developed;
margins serrulate-spiny with teeth ascending;
apex acute or blunt with subapical and apical teeth same size;
microscales filiform, lacking projections, dense, on abaxial surface only.
entire or minutely dentate-erose.
confluent, completely covering abaxial surface of pinnae (only in this species);
indusia entire.
dark brown to blackish.
light brown.
± stalked, rounded, acroscopic auricle not well developed, margins entire to weakly dentate, apex rounded.
= 82.
= 82.
Polystichum lemmonii
Polystichum acrostichoides
Polystichum lemmonii forms sterile hybrids with P. scopulinum and P. munitum. The first hybrid may be abundant where the two parents grow together, which they frequently do in the Wenatchee Mountains of Washington and Siskiyou Mountains of northern California and southwest Oregon. The hybrid is very similar to P. lemmonii but has malformed sporangia and slightly less divided pinnae than P. lemmonii. The P. lemmonii × P. munitum hybrid is morphologically indistinguishable from P. scopulinum; it is a sterile diploid reported only twice from the Wenatchee Mountains of Washington (W. H. Wagner Jr. 1973; P. S. Soltis et al. 1989). It is possible that this hybrid involves P. imbricans and not P. munitum; neither study distinguished between them.
American authors have misapplied the name Polystichum mohrioides (Bory) C. Presl, a South American species, to P. lemmonii.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Polystichum acrostichoides is a common species most closely related to P. munitum (G. Yatskievych et al. 1988), which also occurs extensively on forest floors.
The dimorphic pinnae of Polystichum acrostichoides are not unique to the genus; they are found also in some Asian species. Numerous variants have been named, mostly as forms, but none are of taxonomic consequence. Hybrids are known with P. braunii (P. × potteri Barrington) and P. lonchitis (P. × hagenahii Cody). The latter hybrid is rare, known only from its type locality in Ontario, where it grows with both parents. It is recognized by its intermediate morphology (leaves wider than P. lonchitis, narrower than P. acrostichoides, with slightly contracted sorus-bearing pinnae) and malformed sporangia and spores. Polystichum × potteri is much more widespread, from Nova Scotia, New Brunswick, and Quebec through New England to Pennsylvania. It resembles P. braunii but has narrower leaves bearing malformed sporangia.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
- Local floras:
BC, 
CA, 
OR, 
WA - Local Web sites: CalFlora, CalPhotos,
Flora NW, 
PNW Herbaria 
WildflowerSearch
iNaturalist (observations)
USDA Plants Database- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
Go Botany
IL Wildflowers
KS Wildflowers
LA Plants
MD Biodiversity
MI Flora
MN Wildflowers
MO Plants
