Portulaca family (Portulaceae)
Description: This introduced annual plant forms a spreading mat up to 6" tall and 2' across, branching frequently at the base. The stems are round, thick, and succulent. They range in color from light green to reddish brown. The leaves are alternate or nearly opposite and sessile along the stems. They are up to 1" long and ½" across, obovate or oblong, glabrous, and smooth along the margins. Like the stems, the leaves are rather thick and succulent. They are usually shiny green, sometimes becoming reddish purple in bright sunlight. There is a tendency for the leaves to cluster toward the apex of the stems.
The yellow flowers occur singly or in small terminal clusters. When fully open, each flower is about ¼" across, consisting of 5 yellow petals, 2 green sepals, numerous yellow stamens, and several pistils that are bunched together in the center of the flower. These flowers have floppy petals that open up for a few hours during bright sunny mornings. The blooming period occurs from mid-summer through the early fall and lasts about 1-2 months. Each flower is replaced by a seed capsule that splits open around the middle to release the numerous small seeds. Each seed is dark brown or black, somewhat flattened, and nearly round or kidney-shaped. The surface is granular, appearing somewhat coiled. The root system consists of a taproot. This plant can spread by reseeding itself, or vegetatively, as the broken-off stems can form rootlets to establish new plantlets.
Cultivation: The preference is full sun and mesic to dry conditions. Common Purslane will grow readily in practically any kind of soil containing loam, sand, or gravelly material. The seeds germinate after the weather becomes warm, and they can remain viable in the soil for at least 30 years (Georgia, 1913). Tolerance to heat and drought is excellent.
Range & Habitat: Common Purslane is a common plant that occurs in every county of Illinois. It was introduced into the United States from Europe as early as the 17th century and was used as a potherb or salad herb. Habitats of Common Purslane include rocky bluffs, cropland, gardens, nursery plots, barnyards, cracks in city sidewalks and pavement, and waste areas with sterile soil. This plant prefers highly disturbed areas, and it is common in run-down areas of cities.
Faunal Associations: The flowers attract flower flies, small bees, and beetles (Robertson, 1929). The larvae of Schizocerella pilicornis (Purslane Sawfly) mine the interior of leaves, while the larvae of another Argid sawfly, Schizocerella lineata, feed externally on the leaves of Common Purslane (Smith, 2006). The seeds are a minor source of food to sparrows and closely related songbirds at various times of the year, including Spizella passerina (Chipping Sparrow), Pooecetes gramineus (Vesper Sparrow), and Calcarius lapponicus (Lapland Longspur); see Martin et al. (1951/1961). The Prairie Deer Mouse also eats the seeds (Whitaker, 1966). Some mammalian herbivores feed on the succulent foliage of Common Purslane – examples include pigs and deer (Georgia, 1913). The seeds are able to pass through the digestive tracts of White-tailed Deer and remain viable (Myers et al., 2004). This helps to spread Common Purslane into new areas.
Photographic Location: A flower bed that was overgrown with weeds in Urbana, Illinois.
Comments: The fleshy stems and leaves provide this species with a distinctive appearance. There are cultivated forms of Purslane that are grown in vegetable gardens, which can be eaten fresh or as a potherb. The only other Portulaca sp. that is known to naturalize in Illinois is Portulaca grandiflora (Moss Rose). The Moss Rose has much larger flowers than Common Purslane, and its succulent leaves are linear in shape. This species is from South America and it is often grown in flower gardens because of the attractive flowers. While it occasionally reseeds itself, the Moss Rose rarely persists in the wild state for very long.