Description ²

Plants prostrate annuals (I have found 1 plant overwintering in Gaines Co.); glabrous; plants generally less than 3 cm tall; plants often spreading to 20-30 cm wide, rarely more than 30 cm; plants forming mats of mostly 1 layer of stems. Largest internodes up to 2 mm in diameter at base. Stipules divided into thread-like strands. Leaves mostly oblong; margins entire; leaf bases mostly equal or only slightly unequal. Cyathia usually around 1 mm across or slightly less. Appendages present. Fruits more than 2 mm long. Seeds smooth and plump.

Habitat and Distribution ²

Widespread on the Llano (Turner et. al., 2003; SRSC) in sandy soils. Euphorbia geyeri seems to like somewhat sandier soil than E. glyptosperma but more stable dunes than E. missurica or E. carunculata. Euphorbia geyeri and E. glyptosperma have been observed growing together. It is generally not abundant enough to become weedy.

Comments ²

Euphorbia geyeri looks superficially most similar to Euphorbia glyptosperma. However, E. glyptosperma has minutely serrated leaves (magnification usually needed), very asymmetric leaf bases, smaller cyathia, and ridged seeds. The stems are also usually redder in E. glyptosperma, but this is a variable character. Euphorbia glyptosperma typically likes finer sands while E. geyeri seems to prefer stable, open dunes of coarse sand.

Sources and Credits

1. (c) Nathan Taylor, all rights reserved, uploaded by Nathan Taylor
2. (c) Nathan Taylor, some rights reserved (CC BY-SA)

More Info

• iNat taxon page
• Biodiversity Heritage Library
• BOLD Systems BIN search
• eFloras.org
• Flora of North America (beta)
• Global Biodiversity Information Facility (GBIF)
• HOSTS - a Database of the World's Lepidopteran Hostplants
• IPNI (with links to POWO, WFO, and BHL)
• NatureServe Explorer 2.0
• SEINet Symbiota portals
• Tropicos
• USDA PLANTS database
• VASCAN by Canadensys
• World Flora Online

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