Portulaca oleracea (common purslane, also known as little hogweed, or pursley) is an annual (actually tropical perennial in USDA growing zones 10–11) succulent in the family Portulacaceae. Description The plant may reach in height. It has smooth, reddish, mostly prostrate stems, and the leaves, which may be alternate or opposite, are clustered at stem joints and ends. The yellow flowers have five regular parts and are up to wide. Depending upon rainfall, the flowers appear at any time during the year. The flowers open singly at the center of the leaf cluster for only a few hours on sunny mornings. The tiny seeds are formed in a pod that opens when the seeds mature. Purslane has a taproot with fibrous secondary roots and can tolerate poor soil and drought. The fruits are many-seeded capsules. The seed set is considerable; one plant can develop up to 193,000 seeds. The seeds germinate optimally at a temperature above 25 °C; they are light germinators, with even a soil cover of 5 mm having a negative effect on germination. Metabolism P. oleracea is one of the very few plants able to utilize both CAM and C4 photosynthesis pathways, for a long time believed to be incompatible with each other despite biochemical similarities. P. oleracea will switch from C4 to CAM pathways during drought, and there is transcription regulation and physiological evidence for C4-CAM hybrid photosynthesis during mild drought. Taxonomy P. oleracea was recorded in 1753 by Carl Linnaeus in Species Plantarum. Due to the great variability, a large number of subspecies and varieties have been described as species of their own, but according to other publications, they all fall within the range of variation of P. oleracea. The synonyms P. oleracea subsp. sativa, P. sativa, and P. oleracea var. sativa, which are more common in the literature, refer to a somewhat more robust form in cultivation with larger seeds that cannot be separated from the species. Approximately 40 cultivars of P. oleracea are currently grown. The flowering plant, more commonly known as winter purslane (Claytonia perfoliata), is a member of the Montiaceae family and is not closely related. Etymology The specific epithet oleracea means "vegetable/herbal" in Latin and is a form of (). Distribution and habitat Purslane has an extensive distribution, assumed to be mostly anthropogenic (or hemerochoric), extending from North Africa and Southern Europe through the Middle East and the Indian subcontinent to