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CPC National Collection Plant Profile

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CPC National Collection Plant Profile

Croton alabamensis var. texensis

Family:	Euphorbiaceae
Common Name:	Texabama croton
Author:	Ginzbarg
Growth Habit:	Shrub, Subshrub
CPC Number:	16071

Distribution
Protection
Conservation
References

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Image Owner: Texas State University-San Marcos

Croton alabamensis var. texensis is Not Sponsored

Primary custodian for this plant in the CPC National Collection of Endangered Plants is:

The Lady Bird Johnson Wildflower Center

Croton alabamensis var. texensis

A surprisingly conspicuous semi-evergreen shrub, Texabama croton escaped detection until 1989, when it was almost simultaneously discovered at Fort Hood and on the Balcones Canyonlands NWR. Readily recognized by foliage alone throughout the growing season, particularly in autumn when that foliage turns a bright orange color, the foliage of this large shrub is shiny silvery- to coppery-scaly on the lower surface and is strikingly different from any other plant species of the Edwards Plateau. Var. texensis is quite similar to var. alabamensis, which occurs in a very few locations in central Alabama and south-central Tennessee. According to Ginzbarg (1992), the two varieties differ mostly in the pigmentation of the scales. Texabama croton flowers in late February-March. (TPWD, 2003).

Distribution & Occurrence

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State Range

Texas

Habitat

At Balcones Canyonlands NWR (Travis County), Texabama croton occurs mostly in duff-covered loamy clay soils on rocky slopes in forested mesic limestone canyons, in the shade of Quercus buckleyi, Fraxinus texensis, Juglans major, Prunus serotina subsp. eximia and other deciduous trees. The habitat is similar at Fort Hood Military Installation (Bell and Coryell counties), where additional tree associates include Acer grandidentatum and Quercus muhlenbergii. At both sites, Texabama croton is locally abundant on deeper soils on small terraces in canyon bottoms, often forming large colonies and dominating the shrub layer; scattered individuals are occasionally found on sunny margins of such forests. The habitat at Pace Bend Park (Travis County) is much different. Here the shrubs occur on deep friable soils of a limestone upland, mostly in the shade of evergreen woodland mottes dominated by Quercus fusiformis (TPWD, 2003).

Distribution

Endemic to the eastern Balcones Escarpment of central Texas.

Number Left

� Ft Hood, Bell & Coryell Co.: 20,000 plants (Aplet et. al., 1991). A recent fire affected the largest on-post population (CEMML, 1997)
� Gainer Ranch, Travis Co.: 500-1,000 plants (Ginzbarg, 1992)
� Penn Ranch, Travis Co.: several thousand individuals (Ginzbarg, 1992)
� Pace Bend Park, Travis Co.: 615 plants (Travis County, 2002)
Texabama croton populations located on Fort Hood Military Installation, tracts of the Balcones Canyonlands National Wildlife Refuge, and Pace Bend County Park receive varying levels of protection.

Protection

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Global Rank:	G3T2	5/22/2003	Guide to Global Ranks
Federal Status:			Guide to Federal Status
Recovery Plan:	No

State/Area Protection

	State/Area	Rank	Status	Date
	Texas	S2	SOC

Conservation, Ecology & Research

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Ecological Relationships

The bark is thin and apparently this species is not fire tolerant (Hayden et. al., 2001).

Threats

Fire may be a threat.

Current Research Summary

� Re-introduction of seedlings to both burned over location and unpopulated area on Ft. Hood. (CEMML, 1997)
� Investigation into the effectiveness of accelerated aging techniques as a means of overcoming seed dormancy and stimulating germination (CEMML, 1997).

Current Management Summary

Research Management Needs

� Research needed on recruitment, survival and growth
� Monitor populations

Ex Situ Needs

� Seed banking
� Seed germination studies
� Genetics
� Propagation
� Reproductive ecology studies

References

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Books (Single Authors)

Texas Parks & Wildlife Department. 2003. Guide to the rare plants of Texas. Yet-to-be-published manuscript.

Books (Sections)

Hayden, T.J.; Cornelius, J.D.; Weinberg, H.J.; Jette, L.L.; Melton, R.H. 01 Mar 2001. Endangered Species Management Plan for Fort Hood. Technical Report. U.S. Army, Corps of Engineers, CERL, Champaign, IL, Report Number ERDC/CERL TR-01-26. 1.

Journal Articles

Aplet, G.H.; Laven, R.D; Falkner, M.B.; Shaw, R.B. 1994. Population and site characteristics of a recently discovered disjunct population of Croton alabamensis (Euphorbiaceae). Sida. 16, 1: 37-55.

Ginzbarg, S. 1992. A new disjunct variety of Croton alabamensis (Euphorbiaceae) from Texas. Sida. 15, 1: 41-52.

Newspaper Articles

CEEMML (Center for Ecological Management of Military Lands). 1997. Newsletter 3(2). 4 pp.

Reports

Kral, R. 1983. A report on some rare, threatened, or endangered forest-related vascular plants of the South. United States Department of Agriculture, Forest Service, Technical Publications R8-TP2. p. 1305.

Travis County Parks and Natural Resources. 2002. Monitoring and management of plant species of concern located on the Balcones Canyonlands Preserve in FY2002. Unpublished report. p.66.

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This profile was updated on 3/4/2010