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 can remain viable in the soil for several decades. 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. The seeds of Common Purslane have been observed at some archeological sites in North America, including the remnants of an Amerindian village in Oklahoma that is 5,000 years old. Such findings, if true, would indicate that Common Purslane is also native to the New World, in which case it may be adventive in Illinois from the southwestern United States. However, it's possible that the seeds of the archeological sites are from another species of Purslane that is native to the southwest. Habitats of Common Purslane include rocky bluffs, cropland, gardens, nursery plots, barnyards, cracks in sidewalks and pavement, and waste areas with sterile soil. This plant prefers disturbed areas, and is common in run-down areas of cities.
Faunal Associations: The flowers attract flower flies, small bees, and beetles. 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). Purslane species are an important food source for wildlife in the Western states, but less important in the Eastern states because of the greater availability of other kinds of plants.
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.