Florida Hammock Sandmat (Sandmats (Euphorbia sect. Anisophyllum, previously Chamaesyce) of the Llano Estacado)

Florida Hammock Sandmat

Euphorbia ophthalmica

Description ²

Plants prostrate to ascending annuals (usually ascending when growing with potted plants); hairy; plants observed in pots on the Llano up to 10-15 cm tall but most plants observed 7-10 cm tall. Stem hairs tomentose to woolly to villous, on Llano usually toward tomentose; largest internodes up to 1 mm on plants observed in pots on Llano; terminating in a pair of glomerules. Stipules divided. Leaves unequal rhombic-lanceolate; surface rugose; margins serrated. Cyathia held in glomerules of more than 15 cyathia; cyathia very small, about 0.5 mm across. Appendages present but inconspicuous. Cyathia and appendages usually brown or tannish. Glands a dull pinkish. Fruits about 1 mm long with strigose hairs. Seeds with 4-5 shallow transverse ridges or wrinkles.

Habitat and Distribution ²

Known from the Llano only as weeds in potted plants imported to both Lubbock and Midland from other regions. The plant has not been observed growing outside of potted plants yet.

Comments ²

Plants can easily be distinguished from other species by their rugose, rhombic-lanceolate leaves and dense glomerules of small cyathia. Euphorbia hirta (not yet reported on the Llano) is a similar species with rugose, rhombic-lanceolate leaves and dense glomerules of small cyathia that shares the tendency to travel long distances as weeds with E. ophthalmica. Consequently, E. hirta may eventually show up with future observations. Euphorbia ophthalmica can be distinguished by the stems that terminate in a pair of glomerules instead of bearing glomerules along the stem. Euphorbia hirta also has a habit and leaf size more like that of E. hyssopifolia or E. hypericifolia.

Sources and Credits

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