Stanfield's Beebalm, Monarda stanfieldii

On Oct 30, 2016, botanist Bill Carr led a native plant identification field trip to the private Spicewood Ranch in Burnet County, TX. The field trip was organized by Environmental Survey Consulting.

Bill showed us a population of the Texas endemic Stanfield's Beebalm, Monarda stanfieldii. He admitted that he had originally misidentified it as M. punctata. But on further study realized it was M. stanfieldii.

The major distinguishing feature between these two species is that in M. stanfieldii, the mouth of the calyx is closed by a dense mass of white to silvery hairs. In M. punctata the calyx is open and merely ciliate.

And fortunately, these distinguishing characters can still be observed after the leaves and corollas have dried up and disappeared (as they had in this population in late October).


First, see this photo of M. punctata from eiu.edu. Note that the mouth of the calyx is ciliate, but still open:

Now compare with this photo of M. stanfieldii I took during the field trip. Note that the mouth of the calyx is closed with a mass of white hairs:

You can see even more detailed photos of this specimen in my observation attached below. Be sure to select the "original" size in order to see all the glorious macro detail.

Also, see this Monarda key to Texas species for reference:

https://web.archive.org/web/20090215215401/http://www.lib.utexas.edu/lsl/Mints/monarda/monakey.html

M. stanfieldii has a very limited range, restricted to sandy areas along the Colorado and Pedernales Rivers on or downstream of the Llano Uplift (Blanco, Burnet, Gillespie, Llano and Travis counties). But note that BONAP shows a specimen record from Robertson County. This seems out of range based on the current understanding of the desired ecological region of this species. Here is the M. stanfieldii distribution map from BONAP (Robertson County is the easternmost county in yellow on the map):

Distribution map citation:
Kartesz, J.T., The Biota of North America Program (BONAP). 2015. Taxonomic Data Center. (http://www.bonap.net/tdc). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2015. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]


The details above are summarized from the notes and discussion provided by Bill Carr. Any errors are surely mine.

הועלה ב-נובמבר 4, 2016 09:38 אחה"צ על ידי billdodd