COUNTY RECORDS AND MAJOR RANGE EXTENSIONS FOR ANGIOSPERMS FROM THE LAMPASAS CUT PLAIN OF THE WEST CROSS TIMBERS AND PRAIRIES IN SAN SABA AND MILLS COUNTIES, TEXAS

As conservation ecology and plant restoration become more important due to habitat loss, a well-known flora of an area is essential for making conservation decisions and restoring ecosystems. The Lampasas Cut Plain makes up the largest portion of the Grand Prairie and extends through Bosque, Hamilton, Coryell, Bell, Williamson, Lampasas and Mills Counties (Diggs et al. 1999). Due to the variable topography, microhabitats ranging from nearly soilless slopes to areas of deeper soil create conditions for highly variable vegetation. Depending on the area, The Lampasas Cut Plain vegetation can be compared to that of the Cross Timbers, Edwards Plateau, or Fort Worth Prairie (Diggs et al. 1999).

Both Mills and San Saba counties lie close to the boundary of the Cross Timbers and prairies and Edwards Plateau ecoregions. This creates a species-rich environment of vegetation characteristic of both regions. However, few studies on the flora of this region have been conducted. The purpose of this study is to expand the knowledge of the flora of Mills and San Saba counties. Species collected were identified as native, endemic, or introduced, rare, threatened, or endangered. It is also noted if species appear on the Texas State-listed Noxious Weeds list.

Methods.–Plants were collected along both sides of the Texas Colorado River (the west side in San Saba County, the east being in Mills County), San Saba River, as well as Timberlake Biological Field Station located near Goldthwaite, Texas in June of 2018 (Fig. 1). Specimens were identified as well as classified as endemic, native, or invasive using Shinners and Mahler's Illustrated Flora of North Central Texas (Diggs. et al. 1999) and distribution assessed using Turner et al. (2003a, b). Species collected were also compared to those which occur on the Texas State-listed Noxious Weeds (United States Department of Agriculture 2018), and state threatened and endangered plant species list (Texas Park and Wildlife Department 2018).

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Results & Discussion.–A total of twenty species were collected (Table 1), 15 of them being native and five of them being introduced with none being endemic to Texas. No species are considered to be rare, threatened, or endangered nor present on the noxious weeds list.

Eleven new county records were collected for Mills County and nine for San Saba County. Two species (Morus rubra from Mills County and Cynodon dactylon from San Saba County) were major range extensions. Details of the major range extensions are discussed in the following paragraphs.

FAMILY POACEAE

Cynodon dactylon (L.) Pers. (Bermuda Grass; Tarleton State University accession number N-2410) is a common wide-spread introduced grass cultivated in North-Central Texas since around 1882 for use in pastures. Although its origin is uncertain, it is thought to possibly be native to Africa or India (Diggs et al. 1999). The presence of this species in San Saba County (Turner et al. 2003a) confirms and extends broad use of Bermuda grass in pastures across Texas.

FAMILY MORACEAE

Morus rubra L. (Red Mulberry; Tarleton State University accession number N-2413) is a native tree found along stream bottoms and is common in southeast and eastern Texas throughout the Rolling Plains and Edwards Plateau ecoregions (Digg et al. 1999). Presence of this species in Mills County (Turner et al. 2003b) extends the range of this plant into the southwestern-most-part of the Cross-Timbers and Prairies ecoregion.