Leaf dimensions plotted for 50 test group leaves (green triangles) collected in late January 2013. The test group was in full sun, so comparison was made with H. drummondii leaves from plants in full sun (red squares) (from Hays & Travis Cos.), in shade (red diamonds; Hays Co.; noted because they had atypically broad leaves for H. drummondii, and winter leaves (pink circles; Hays Co., in sun). Winter leaves of all taxa are those low cauline leaves with distinctly stronger pubescence. By mid winter H. drummondii winter leaves had mostly fallen off — in stark contrast with H. reverchonii var. serpyllifolia, which keeps them well into April. I had no access to H. reverchonii var. reverchonii at that time.
Results of late January/early February lower cauline leaf measurements,
50 H. reverchonii var. serpyllifolia plants (N1 to N50)
by Bob Harms
The above scatter plot of leaf dimensions for H. reverchonii var. serpyllifolia shows only minor variation for winter leaves, approximately the same as for H. drummondii plants in full sun, and the two taxa don't overlap at all. This same distinction for leaf dimensions was found at all other phases.
| | W (mm) | L (mm) | L/W ratio |
| average | 4.3 | 7.2 | 1.7:1 |
| range | 3.2-5.5 | 4.9-10.4 | 1.2–2.2:1 |
| |
| Values for leaves shown in the table below |
| N1 | 4.2 | 7.3 | 1.7:1 |
| N3 | 4.0 | 4.9 | 1.2:1 |
| N7 | 4.2 | 7.0 | 1.7:1 |
| N10 | 4.8 | 6.7 | 1.4:1 |
| N15 | 3.2 | 4.9 | 1.5:1 |
| N19 | 4.2 | 6.0 | 1.4:1 |
| N21 | 4.3 | 7.4 | 1.7:1 |
| N29 | 4.1 | 7.1 | 1.7:1 |
| N30 | 5.5 | 8.3 | 1.5:1 |
| N33 | 4.3 | 7.3 | 1.7:1 |
| N36 | 5.4 | 9.5 | 1.8:1 |
| N37 | 4.4 | 7.4 | 1.7:1 |
| N43 | 4.6 | 10.0 | 2.2:1 |
| N50 | 4.5 | 8.3 | 1.8:1 |
Images of 15 leaves collected for the January/February lower cauline leaf measurements. Selection includes the extremes for each category as well as those with average values. These have been reduced to 40% of the original 2400 dpi scan — their sizes are proportionate. [Click on a leaf for its full-size image.]
Plant Resources Center Home Page — Flora of Texas
— Hedeoma
