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Dryopteris expansa

Higher Taxonomy
Family: DryopteridaceaeView DescriptionDichotomous Key

Habit: Perennial herb, in soil or rock crevices; rhizome generally short-creeping, suberect, or erect, scales large, generally tan to brown, generally uniformly colored. Leaf: generally tufted, 5--200+ cm, generally +- alike; stipe generally firm, base generally darker, with many vascular strands; blade 1--4-pinnate, often with scales, hair-like scales, hairs (except clear, needle-like hairs generally 0), or short-stalked glands on axes, between veins or not, veins free to netted; rachis, costa generally grooved adaxially. Sporangia: sori round, along veins; indusia peltate or round-reniform; spores elliptic, winged, ridged, or spiny, scar linear.
Genera In Family: +- 40--45 genera, > 1600 species: worldwide, especially tropics, wooded areas. Note: Based on molecular sequence data, Athyrium, Cystopteris, Woodsia removed to Woodsiaceae to preserve a monophyletic Dryopteridaceae.
Unabridged Note: Current data (as reported by Schuettpelz & Pryer and in papers cited therein) suggest that Wooodsiaceae is paraphyletic (with respect to Aspeniaceae, Blechnaceae, and Thelypteridaceae), yet are insufficient to resolve the questions of circumscription (too few taxa, not enough genes sampled). Alternative classifications that would preserve monophyly include recognition of several additional, small families (e.g., Cystopteridaceae, Athyriaceae, and others not in California, each comprising just a few genera) or lumping at least 4 currently recognized families, many of long-standing use and acceptance; a conservative and expedient course is taken for now (Smith et al. 2006), pending further work.
eFlora Treatment Author: Alan R. Smith
Scientific Editor: Thomas J. Rosatti.
Genus: DryopterisView DescriptionDichotomous Key

Common Name: WOOD FERN
Habit: Rhizome short-creeping or ascending to suberect, stout. Leaf: stipe > 1.5 mm wide, firm, more densely scaly than midrib, base ×-section with many round vascular strands in an arc; blade >= 1--3-pinnate, proximal pinnae reduced or not, veins free, simple or forked; segments deeply pinnately lobed or not. Sporangia: sori round; indusium round-reniform, +- centrally attached at a sinus, generally persistent.
Species In Genus: +- 100 species: +- worldwide, especially eastern Asia. Etymology: (Greek: oak, fern) Note: Hybrids unknown in California, frequent in eastern North America.

Dryopteris expansa (C. Presl) Fraser-Jenk. & Jermy
Leaf: 30--80(100+) cm, 10--30(40) cm wide; stipe generally darker abaxially, scales generally with a dark central stripe; blade broadly deltate, +- 3-pinnate, proximal pinnae > others, sides strongly unequal, basiscopic pinnules > 2 × acroscopic on same pinna, segments deeply pinnately lobed, teeth with bristle-like tips or not, veins generally not into teeth; longest pinnae near base. Chromosomes: 2n=82.
Ecology: Caves, shaded, wooded areas, especially banks of streams; Elevation: < 500 m (1300 m in MP). Bioregional Distribution: NCo, NCoRO, CCo, MP (caves in Lava Beds National Monument); Distribution Outside California: to Alaska, Canada, Rocky Mountains.
Synonyms: Dryopteris assimilis S. Walker
eFlora Treatment Author: Alan R. Smith
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Next taxon: Dryopteris filix-mas

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botanical illustration including Dryopteris expansa


Citation for this treatment: Alan R. Smith 2016. Dryopteris expansa, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on October 24, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora,, accessed on October 24, 2016.

Geographic subdivisions for Dryopteris expansa:
NCo, NCoRO, CCo, MP (caves in Lava Beds National Monument);
Markers link to CCH specimen records. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues. Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
map of distribution 1
(Note: any qualifiers in the taxon distribution description, such as 'northern', 'southern', 'adjacent' etc., are not reflected in the map above, and in some cases indication of a taxon in a subdivision is based on a single collection or author-verified occurence).

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Data provided by the participants of the Consortium of California Herbaria.
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CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa.
Blue line denotes eFlora flowering time.