Top of a perfect (central) floret.
Chaptalia texana & Chaptalia carduacea: Style Branches & Anther Tubes of Perfect Florets
by Bob Harms
The morphology of perfect (central) florets for both species appears to vary on a seasonal basis.
Perfect florets. Early spring (February to early April)
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In early spring phase (February to Early April) at the onset of anthesis the anther tube extends above the 5–lobed floral tube, and also rises above the pistillate florets. The style branches, appressed, push forth clumps of pollen, which then appears to be distributed over the pistillate style branches.
Perfect florets. End of April (late spring transitional)
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Although in late spring C. texana on April 28, 2010 (rightmost photo) followed the early–spring morphology, specimens of both species in late April typically seemed to be transitional between early spring and fall phases, the anther tube not as exserted but with some evidence of pollen grains limited to the exserted style branches of the perfect florets.
Perfect florets. May—June to fall.
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In May—June (first 2 images) and in fall/winter phase the anther tube remains within the floral tube or nearly so, and the style branches, spread or slightly separated, may emerge or not. In May—June a few pollen grains seemed to be found on some perfect style branches, and when dissected the anther tubes revealed pollen, but much less than with early spring florets, and it was not expelled by the style branches. There is no no clear evidence of pollen grains on the style branches in fall/winter phase. (This remains to be investigated more thoroughly).
Dissected perfect florets with minimal pollen, May—June.
A: Exserted style branches, but not the anther tube. Pollen seems to remain in the anther tube;
B—C: Buds of developing florets (A is from the same head as B). The style branches appear to be above the pollen.
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Plant Resources Center Home Page — Flora of Texas
— Chaptalia
