Flora of North America species comparison

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Polystichum kruckebergii

holly fern, Kruckeberg's holly fern, Kruckeberg's sword fern, Kruckeberg's sword fern fern
Stems

ascending.
Leaves

erect, 1–2.5 dm;

bulblets absent.
Petiole

1/10–1/5 length of leaf, sparsely scaly;

scales light brown, gradually diminishing in size distally.
Blade

linear, 1-pinnate-pinnatifid, base narrowed.
Pinnae

rhombic-ovate to short-falcate, proximal pinnae ± triangular;

pinnae overlapping, twisted somewhat out of plane of blade, 0.5–1.5 cm;

base oblique, acroscopic auricle well developed;

margins shallowly incised to merely dentate or serrulate, teeth spreading and spiny at tip;

apex acute with subapical and apical teeth same size;

microscales lanceolate with few projections, confined to costa, on abaxial surface only.
Indusia

entire.
Spores

dark brown.
2n

= 164.

Polystichum kruckebergii
Habitat Rocks and cliffs in subalpine to alpine habitats
Elevation 1500–3200 m (4900–10500 ft)
Distribution
from FNA
CA; ID; MT; NV; OR; UT; WA; BC
[WildflowerSearch map]
[BONAP county map]
Discussion

Polystichum kruckebergii is widely but sporadically distributed in small numbers in both the Sierra-Cascade and Rocky Mountain systems. Populations sometimes consist of only two or three dwarfed plants that are difficult to distinguish from P. scopulinum, with which they may occur. The spreading teeth of equal size at the pinna apex will usually distinguish this species. Polystichum kruckebergii is a tetraploid presumed to be of hybrid origin, with P. lonchitis and P. lemmonii as its diploid progenitors (W. H. Wagner Jr. 1973), although this hypothesis has not been confirmed. The hybrid with P. munitum has been found in Washington (P. S. Soltis et al. 1987) with both parents, and it is distinguished by intermediate morphology and abortive sporangia.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 2.
Parent taxa Dryopteridaceae > Polystichum
Sibling taxa
P. acrostichoides, P. aleuticum, P. andersonii, P. braunii, P. californicum, P. dudleyi, P. imbricans, P. kwakiutlii, P. lemmonii, P. lonchitis, P. microchlamys, P. munitum, P. scopulinum, P. setigerum
Name authority W. H. Wagner: Amer. Fern J. 56: 4. (1966)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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