Spotted Spurge

Euphorbia maculata

Description 6

Plants prostrate annuals, ascending in shade or competition; plants hairy; plants typically not more than 15 cm tall; usually forming mats less than 20 cm., individual stems generally less than 10 cm but may get to 20 cm or more. Largest internodes up to 2 mm in diameter. Stipules divided. Most leaves generally oblong and greatly unequal at the base; usually has a reddish-purplish “splotch” on the leaf but some individuals may have leaves that lack them; top of leaves usually glabrate to glabrous; shallowly serrated. Hair on fruits strigose. Seeds with shallow, rounded transverse ridges, often less whitened at the top of the ridges than other parts of the seed.

Comments 6

When reading descriptions like the one in Manual of the Vascular Plants of Texas (Correll and Johnston, 1979), it can be difficult to distinguish E. prostrata from E. maculata without looking at the seeds or hairs. The leaves are also quite different and can provide a good character to differentiate the two, especially in combination with the other characters:

Euphorbia maculata: Oblong leaves often with a reddish or purplish “splotch” on them (not always); leaf bases more unequal than E. prostrata; hairs on fruits always appressed, not restricted to the angles; ridges on seeds rounded.
Euphorbia prostrata: Oval to rotund leaves always lacking a "splotch"; leaf bases more equal than E. maculata (still unequal); hairs on fruits generally not appressed, restricted to the angles; ridges on seeds coming to a sharp edge.

Because of the abundance of these two species as lawn and garden weeds, it is usually fairly easy to find the two species to compare.

During the 1930's and 1940's, Louis Cutter Wheeler (the Euphorbia expert of the time) called this species E. supina while giving the name E. maculata to a different species, now known as E. nutans, based on some misunderstanding of the type specimen. This has long since been resolved with the name E. maculata representing the smaller plant and E. nutans representing the larger plant (photos can be found here). Occasional specimens representing this outdated taxonomy can be found. For more information concerning this, please read The application of the Linnaean names of some New World species of Euphorbia subgenus Chamaesyce by Daniel Burch (1966, Rhodora 68:155–166; also available on JSTOR).

For information regarding spotted spurges without "spots", please read here.

Sources and Credits

  1. (c) nathantaylor, some rights reserved (CC BY-NC-SA), uploaded by Nathan Taylor, http://www.inaturalist.org/photos/5167605
  2. (c) nathantaylor, some rights reserved (CC BY-NC-SA), uploaded by Nathan Taylor, http://www.inaturalist.org/photos/5167435
  3. (c) nathantaylor, some rights reserved (CC BY-NC-SA), uploaded by Nathan Taylor, http://www.inaturalist.org/photos/5167436
  4. (c) nathantaylor, some rights reserved (CC BY-NC-SA), uploaded by Nathan Taylor, http://www.inaturalist.org/photos/5167437
  5. (c) nathantaylor, some rights reserved (CC BY-NC-SA), uploaded by Nathan Taylor, http://www.inaturalist.org/photos/5167438
  6. (c) Nathan Taylor, some rights reserved (CC BY-SA), http://www.inaturalist.org/guide_taxa/346778

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