The two columns below show Hedeoma calyxes at first anthesis. 12 H. reverchonii var. serpyllifoia, from 8 different plants of the same population in N. Hays Co., 28–30 April 2014, are shown in the left column. The right column shows 14 calyxes collected 6 May 2014 from H. drummondii from W Travis Co. and central Hays Co. (6), H. reverchonii var. reverchonii from W Travis Co. (4), and a hybrid from central Hays Co., assumed to represent H. drummondii × H. reverchonii var. serpyllifoia (4).

Yellow lines mark the calyx base and the base of the upper teeth. A vertical scale (2 mm) has been positioned in the area of the longest hairs.

The two columns can be scrolled independently in order to compare those in the right column with H. reverchonii var. serpyllifoia individuals.