Adenothamnus D. D. Keck

March 15, 2000.  Each "thumbnail" image below is linked to a larger photograph.

Adenothamnus is a  rare, monotypic genus of perennial shrubs from Baja California.  Heads radiate, large, phyllaries several, each completely enveloping a ray ovary; receptacular chaff peripheral, uniseriate, and coalesced into a cylindrical, false involucre; ray flowers pistillate, corollas very conspicuous, bright yellow; disk florets perfect, corollas bright yellow; anthers dark purple; ray pappus absent; disk pappus comprising about 15-20 somewhat flattened bristles.  The chromosome number is n = 14.


ade_val_mids.jpg (9752 bytes) ade_val_hds.jpg (9451 bytes) ade_val_hd2s.jpg (9425 bytes)
ade_val_raylesss.jpg (7496 bytes) ade_val_frs.jpg (9640 bytes)
A. validus.  1 - Flowering shoot bearing linear, alternate leaves, 2 - Flowering head, intact, 3 - Flowering head partially dissected to show false involucre, 4 - Once all ray florets and subtending phyllaries are removed, the head looks very similar to rayless heads found in the related genera Dubautia and Carlquistia.  5 - Fruiting head showing the nature of the pappus on disk achenes.

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