Onoclea

Linnaeus
Sp. Pl. 2: 1062. 1753; Gen. Pl. ed. 5, 484, 1754.
Common names: Sensitive fern
Etymology: Greek onos, vessel, and kleiein, to close, in reference to the sori, which are enclosed by the revolute fertile leaf margins
Treatment appears in FNA Volume 2.

Plants terrestrial. Stems creeping, stolons absent. Leaves strongly dimorphic, fertile leaves usually shorter, greatly contracted, persistent 2–3 years, sterile leaves dying back in winter. Petiole of sterile leaf ca. 1–1.5 times length of blade, petiole of fertile leaf 2–6 times length of blade, bases swollen and persisting as trophopods over winter; vascular bundles 2, lateral, lunate in cross section. Blade of sterile leaf deltate, pinnatifid to pinnate-pinnatifid proximally, reduced and shallowly pinnatifid distally, herbaceous to papery, blade of fertile leaf linear-oblong, 2-pinnate, leathery. Pinnae not articulate to rachis, segment margins of sterile blades entire to sinuate or shallowly lobed, margins of fertile pinnules strongly revolute and forming hardened beadlike structures; proximal pinnae largest or nearly so, sessile or adnate, equilateral; costae adaxially flat; indument on both sides of linear to lanceolate scales and/or multicellular hairs on rachis and costae. Veins reticulate with areoles lacking included veinlets in sterile leaves, veins free in fertile leaves. Sori covered by strongly revolute margins of pinnae, ± round; indusia vestigial, triangular, persistent but not easily seen in mature leaves. Spores greenish, with a few low folds and numerous, minute, echinate-cristate elements. x = 37.

Distribution

Temperate regions in Northern Hemisphere, Asia.

Discussion

Onoclea is one of several genera known to store starch grains in long-persistent petiole bases (trophopods) (W. H. Wagner Jr. and D. M. Johnson 1983).

Species 1 (1 in the flora).

Selected References

None.

Lower Taxa

... more about "Onoclea"
David M. Johnson +
Linnaeus +
Sensitive fern +
Temperate regions in Northern Hemisphere +  and Asia. +
Greek onos, vessel, and kleiein, to close, in reference to the sori, which are enclosed by the revolute fertile leaf margins +
Onoclea +
Dryopteridaceae +