Wednesday, November 24, 2010

central Sierra Camissonia seedlings

Camissonia sierrae ssp. alticola
Little Yosemite Valley
DWT #20938 (JEPS, YM) 16 July 2010
Camissonia sierrae ssp. alticola
Little Yosemite Valley
DWT #20938 (JEPS, YM)

There are distinct differences in the seedlings of two species of Camissonia in the Yosemite Region. In Camissonia sierrae ssp. alticola Little Yosemite Valley, the colytedons are of quite different shape from those in C. laucustris Wawona, as pictured (red arrow in each photo).

In C. sierrae, the cotyledons are initially rhombic in shape, but later become lanceolate; they lack ciliate margins which can be seen on the first foliage leaves, and are entire margined. The plants at 7 weeks of age form a distinct rosette.

By contrast, C. laucustris Wawona produces cotyledons which are linear and distinctly emarginate. Moreover, during development, their cotyledons elongate markedly, becoming 15-20 mm long and are similar to the first foliage leaves.

The differences in early development of these two species makes their seedlings relatively easy to identify, if one could find them in the field.

More species need to be grown out to ascertain if these differences form morphological classes within the genus, and if the morphological differences have classificatory and/or phylogenetic value.

Camissonia lacustris

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