California Maidenhair

California maidenhair (Adiantum jordanii) is a delicate fern arising from a slender, creeping rhizome. Ferns have their own descriptive terminology. Although they photosynthesize like flowering plants, the life cycle of a fern is different with gametophyte and sporophyte stages and the production of spores rather than seeds.

The several fronds (much divided leaves) of California maidenhair have dark brown to black stipes (stems) that are about as long as the blades. The blades (expanded portion of the frond) are pinnate (branching on both sides of the axis) with the ultimate segments broadly fan shaped. The sori (clusters of sporangium or sacs in which the spores are formed) occur in a band along the distal leaf margin and a false indusia (epidermal outgrowth) is formed by the recurved leaf margin. The sori of California maidenhair are linear and there is a shallow incision along the leaf margin between two successive sori.

A native perennial, California maidenhair grows in seasonally moist, shaded, rocky banks, canyons and ravines below 3,500 feet. It can be found in California and Southeastern Oregon. It is a member of the Brake Family (Pteridaceae).

California maidenhair is a carrier of the fungus-like organism Phytophthora ramorum which causes sudden oak death.

The genus Adiantum is from the Greek “adiantos” meaning “unwetted or unwetable” and refers to the way the fronds repel water. Rudolph Jordan Sr (1818 – 1910) was a German-born businessman and entrepreneur. He took specimens from his travels to the University of Halle in Germany to be studied. One specimen, which honors him with its specific epithet, was A jordanii.

These California maidenhair ferns were growing along Bear Gulch Trail in Pinnacles National Park (CA) and were photographed in May.

Another species of maidenhair fern, five-finger maidenhair (Adiantum pedatum) was discussed in one of my previous posts on 01-27-12.

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2 Responses to California Maidenhair

  1. Gunta says:

    Here on the ocean side of the Kalmiopsis-Siskiyous we seem to have more of the five-finger maidenhair (Adiantum pedatum) ferns. We are having problems with sudden oak death spreading to our tan oaks. It makes me wonder if the five-finger maidenhair is also apt to spread the disease. I noticed you didn’t mention it in your older post. I’ve also heard it is known to spread through our wild Rhododendrons. They mowed down huge swaths of tan oaks up in the National Forest (or maybe it was BLM areas near us.


  2. tonytomeo says:

    This is abundant in the riparian area downstairs. Adiantum aleuticum is native here also, but strangely, does not seem to grow in the same places. For example, I do not remember seeing Adiantum aleuticum anywhere around here, where the Adiantum jordanii is common. However, a few colonies of it live on another property a few miles away, where there is no Adiantum jordanii. Adiantum capillus-veneris lives in riparian situations around the edges of the Santa Clara Valley.


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