Ligulate Pistillate Flowers


Open–head with large ligules.	Closed–head with small, but visible, ligules.	Closed–head with reduced ligules
C. texana	C. carduacea

The greatest floret differences are found among the peripheral series of ligulate pistillate flowers. Ligule size, corolla length, pappus length vary considerably among the three major types. The color of older ligules was distinct in the two populations under study: with C. carduacea they turn crimson; with C. texana, yellow (to orange). And in late spring and fall/winter both species, regardless of early spring type, exhibit peripheral florets with reduced ligules and/or lengthened tubular (filiform) corollas corresponding to the ligules of early spring heads.

In addition to longer corollas C. texana also had significantly shorter pappus — providing ready access to pollinators during early anthesis.

	floret length	corolla length^*	pappus length
	average	range	average	range	average
C. texana	12.6 mm	11-13.2 mm	same as floret	9.4 mm
C. carduacea: small ligules	11.4 mm	10.2-12 mm	same as floret	12 mm
C. carduacea: reduced ligules	10.9 mm	10-11.3 mm	8.9 mm	7.9-9.3 mm	12.9 mm

A separate subpopulation of C. carduacea never produces exserted ligules (even in early spring), but the greatly reduced ligules can be seen at anthesis by dissecting the heads, or later, after they turn crimson and the florets are raised above the involucre (as in the top right image). The floret in the lower image appears to have a small second lip, not generally present with the ligulate florets, and more characteristic of the peripheral long–tubular florets.