Nodding Patterns with Chaptalia texana Closed–Heads Type II
by Bob Harms  email-here

Multiple heads on several plants showing the full range of nodding behavior, May 8

The nodding behavior typical of C. texana in the Texas hill country with heads closed at anthesis and visible ligures is illustrated by the two tightly associated plants in the above photo. The pattern is as follows:

  1. The peduncle of the early bud bends downward ±180° but begins to straighten as it lengthens.
  2. As the bud develops, the peduncle continues to straighten and the bud no longer faces downward.
  3. With anthesis the peduncle leans to one side and the apex bends downward.
  4. As the head develops further, the angle of the bend increases, often to over 180°
  5. As the head dries prior to dispersal the peduncle begins to bend upward.
  6. With dispersal the very top of the peduncle approaches (or reaches) an erect position, generally hidden by the globose cluster of pappus/achenes. The image below shows it bending at a slight angle. [Contrast, however, the gradual bend of the larger bud with that of the straightened postdispersal peduncle in the background in the photo for stage II. For additional details.]

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