The purpose of this guide is to aid in the identification of the sandmats that are commonly found in lawns, gardens, potted plants, or otherwise growing as a weed in Texas. These spurges can be easily distinguished from other species of Euphorbia by their opposite leaves, distinctive stipules, ...more ↓
The purpose of this guide is to aid in the identification of the sandmats that are commonly found in lawns, gardens, potted plants, or otherwise growing as a weed in Texas. These spurges can be easily distinguished from other species of Euphorbia by their opposite leaves, distinctive stipules, and generally asymmetric leaves. These are also the only Euphorbias that have C4 photosynthesis and the corresponding Kranz anatomy (intricate pattern of darker bundle-sheath cells surrounding veins with lighter areas in between). Another character that is unique to the sandmats is the sided nature of their stems. Even on the species that are nearly erect, there is a distinguishable upper and lower side to the stems.
In reality, any annual species within this group could be considered a weed. This list primarily includes annual plants that grow throughout Texas, spread easily via potted plants, and have become common or are so common throughout Texas (like E. glyptosperma) that they occur throughout the state. This is far from a complete list and excludes Trans-Pecos, and South Texas endemics.
In the Trans-Pecos, there is an especially large number of "weedy" species that aren't on this list. If the species you have doesn't look like any of these, I would recommend Manual of the Vascular Plants of Texas. Some possible weedy species include: E. abramsiana, E. micromera, E. serpyllifolia, E. serrula (extending N into the High Plains), and E. vermiculata (only known from Alpine). In South Texas, E. berteroana, E. laredana, and E. velleriflora might be possibilities.
Euphorbia species of the United States project
Sandmats of the World project
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The Weedy Species of Sandmats (Euphorbia sect. Anisophyllum) in Texas
