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twin-sorus fern

Habit Plants terrestrial or on rock.
Stems

creeping, ascending, or erect, stolons absent.

Leaves

monomorphic, evergreen or dying back in winter.

Petiole

ca. 1/2 to equaling length of blade, base swollen and persisting as trophopod over winter or not;

vascular bundles 2, lateral, lunate in cross section.

Blade

oblong-lanceolate to deltate, 1-pinnate to 2-pinnate-pinnatifid [simple to 4-pinnate-pinnatifid], gradually reduced distally to pinnatifid apex or apical pinna similar to (conform) adjacent pinnae, herbaceous to papery.

Pinnae

not articulate to rachis, segment margins entire, crenulate, or serrate;

proximal pinnae not reduced, sessile, equilateral or inequilateral;

costae adaxially deeply grooved, grooves continuous with that of rachis;

indument abaxially absent or of linear to ovate scales, adaxially absent.

Veins

free, simple or forked, or basal pairs of adjacent segments anastomosing.

Sori

single or paired back-to-back on veins, oblong to linear, straight or slightly falcate;

indusia linear, laterally attached, persistent.

Spores

brownish, usually broadly winged.

x

= 40, 41.

Diplazium

Distribution
from USDA
Worldwide
[BONAP county map]
Discussion

In a few species outside the flora, rachises and costae bear multicellular hairs like those of Deparia, which differs from Diplazium in having grooves of costae not decurrent onto rachis groove, veins free or anastomosing, sori long or short and costular, and indusia present or absent. Many species of Diplazium are known to reproduce apogamously.

Species about 400 (3 in the flora).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key
1. Leaves 2-pinnate; veins anastomosing.
D. esculentum
1. Leaves 1-pinnate or 1-pinnate-pinnatifid; veins free.
→ 2
2. Scales brown, entire; pinnae nearly entire.
D. pycnocarpon
2. Scales dark brown, dentate; pinnae lobed.
D. lonchophyllum
Source FNA vol. 2. Author: Masahiro Kato.
Parent taxa Dryopteridaceae
Subordinate taxa
D. esculentum, D. lonchophyllum, D. pycnocarpon
Synonyms Homalosorus
Name authority Swartz: J. Bot. (Schrader) 1800(2): 4, 61. (1801)
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