Sunday, May 3, 2015

Botanical Terms...A Visual for Suborbicular

Three species of Prairie Star or Fringecup are present in Montana and other parts of the American West. Line drawings and written botanical descriptions (keys) are confusing, unclear and somewhat contradictory on how to separate and identify Lithophragma glabrum and Lithophragma parviflorum. This situation will continue to crop up for all kinds of fauna as our knowledge expands (variation and hybrids). No doubt, photos and line drawings cannot be done for every plant part. So, language must be used to precisely describe plant parts. And plant descriptions are really ripe for some good nature smirking/what-the-heck head scratching.

Here's the leaf blade description from Lesica (2012) for A) Lithophragma glabrum and B) Lithophragma parviflorum:
A) "glabrous below, sparsely hairy above, 5-20 mm wide, reniform, deeply 3-lobed and lobed again."
B) "white-hairy and glandular, 1-3 cm wide, suborbicular, twice deeply 3-lobed ."

Reniform means "kidney shaped" and suborbicular describes imperfectly circular. The leaf shapes don't sort the plants out by my eye using the photos below. On the other hand, leaf hairiness is distinct and quickly separates out the two species. The first key (Lesica 2012) in sorting these species is the number of lobes per flower petal; glabrum has five and parviflorum has three.

Reference: Manual of Montana Vascular Plants, Peter Lesica, 2012, Brit Press, Fort Worth, TX

Here's what they look like:
Lithophragma glabrum flower
Lithophragma glabrum stem leaf

Lithophragma glabrum basal leaf
Lithophragma parviflorum flower
Lithophragma parviflorum stem leaf

Lithophragma parviflorum basal leaf