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Argyrochosma limitanea subspecies limitanea. Synonym: Pellaea limitanea. (Cloak Fern) Pteridaceae (Maidenhair Fern Family). Synonyms: Cheilanthaceae, Polypodiaceae. Semi-desert. Rocks.
Spring. Argyrochosma limitanea enjoys rocky, sandy crevices. The plants shown in the photographs were all in north facing rocks, but one botanical text indicates the plant is found in south facing rocks. Leaves are 3-5 times pinnate, triangular to deltate, 2-7 inches long and 2-5 inches wide, on dark, glabrous stems. The lower side of the leaves is covered with a white, mealy material that makes the plant distinctive. (See below.) The upper surface is glabrous. The sori (clusters of the spore-bearing sporangia) are usually continuous along the margins of the underside of the leaf segments. Plants grow from rhizomes and can spread over a number of feet -- as shown here, about five feet. For more detailed descriptive material, see the Flora of North America. Argyrochosma limitanea was first collected for science by Elmer Wooten in southern New Mexico in the early 1900s. Maxon described the plant and named it Notholaena limitanea. Windham renamed it Argyrochosma limitanea in 1987. Greek gives us "argyros" ("silver") and "chosma" ("powder") for the white, mealy, powder, on the leaves. According to most botanical authors, this farinose coating is just on the lower side of the leaves, but it is clearly visible on both surfaces in the photographs on this page. "Limitanea" is from the Latin for "limes" ("the border" or "limit") and "anea" ("pertaining to"), thus, "that which is on the border", referring to the type location along the New Mexico/Mexico border. |
Argyrochosma limitanea subspecies limitanea. Synonym: Pellaea limitanea. (Cloak Fern) Semi-desert. Rocks.
Spring. The top side of the leaf shown at left is unusual in having some white-mealy material scattered on its surface. This white coating is usually just on the lower surface and is quite thick. The spherical structures scattered on the lower surface (third photograph at left) are the sori which grow in the spring. The photograph was taken in the fall and most sori have fallen from the leaf. |
Range map © John Kartesz,
County Color Key
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Range map for Argyrochosma limitanea |