Chaptalia texana specimens in the TEX/LL collections
by Bob Harms  email-here

Questions concerning the status of the trimorphic and bimorphic heads in Texas Chaptalia texana led me to examine carefully the 40 Texas specimens in the TEX/LL collections. My results are given in the following tables.

[For documentation of individual specimens.]

Trimorphic (ligulate) and bimorphic specimens:

month total clearly
trimorphic with
reduced ligules
bimorphic lacked
March 16 15 1 0 0
April 13 10 2 0 1
May 2 1 0 0 1
August–November 9 3 3 2 1
Total 40 29 6 2 3

All but two of the specimens are trimorphic. Three quarters are from early spring – March, April & May – the two bimorphic specimens were from late November.

Other features of C. texana in Central Texas, not always clearly detailed in the literature, are (i) the heads are often (but not always) ‘nodding’; and (ii) the heads commonly do not open. Cf. M. Enquist, Wildflowers of the Texas Hill Country (1987), p. 250:

Naked peduncles 3-12" long carry the nodding, cylindrical flower heads. The heads are 1/2-1" long and remain tightly compacted until it is time to release the mature seed, at which time they expand into globe-like seedheads.
The pressed herbarium specimens in general were not mounted in a manner that permits an analysis of the nodding behavior of C. texana. [For details of nodding based on fresh specimens.]

The open heads of C. texana exhibit a diurnal cycle. A closed–head bloom, could perhaps be both less obvious and even if noticed, less likely to be collected (considered not yet in flower, or not yet open). This might account for the relatively small number of Chaptalia texana collections in the TEX/LL holdings (as seen in the table at the bottom of this page). Unfortunately the collections do not allow determination of the closed/open head distinction, nor is any note of this found with the specimens. One specimen appears to have had an open head (Medina Co., E. R. Bogusch 807 [LL]), and only five others might have had an open head.

Number of specimen collections for various Central Texas Asteraceae in TEX/LL:

Thymophylla pentachaeta 322 Liatris punctata var. mucronata 77
Ratibida columnifera 306 Grindelia lanceolata 71
Tetraneuris scaposa var. scaposa 296 Vernonia lindheimeri 64
Tetraneuris linearifolia 243 Chrysactinia mexicana 62
Engelmannia peristenia 193 Grindelia nuda 60
Cirsium texanum 175 Solidago nemoralis 60
Erigeron modestus 168 Tetragonotheca texana 49
Liatris punctata var. punctata 151 Dysodiopsis tagetoides 44
Centaurea americana 136 Chaptalia texana 40
Chaetopappa asteroides var. asteroides 108 Brickellia cylindracea 37
Erigeron philadelphicus 98 Ageratina havanensis 29
Centaurea melitensis 89 Verbesina lindheimeri 22

Plant Resources Center Home PageFlora of TexasChaptalia texana