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.
|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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