Cream Pea is a native erect twining perennial vine, with smooth slightly angled stems, growing from one to three feet.
The leaves are compound, pinnately divided into 3 to 5+ pairs of leaflets, without a terminal leaflet, and instead, a tendril at the tip. The leaflets are virtually stalkless as the stalk is minute. Leafets are ovate to elliptical in shape, with a rounded but asymmetrical base and tapering to pointed tip that has a minute projection of the main leaflet vein. Margins are smooth but a bit wavy. The color is initially green but turns to a dusky purplish-bronze. The upper surface is smooth while the underside is paler in color and showing a fine networked vein pattern. Leaflets are 1 to 2 inches long and 1/2 as wide. At the base of the leaf are a pair of large ovate stipules, rounded at the base but with pointed tips. Leaf stalks have a purplish color.
The inflorescence is a stalked raceme of 5 to 10 stalked flowers, the raceme stem shorter than the leaves and also purplish in color.
The flowers are typical pea-like, 5-parted, about 3/4 inch long with a calyx that is greenish-cream with faint vein lines and varying to creamy with pinkish tones shading to more creamy on the tip with deeper pinkish color veining. The calyx is about 1/3 the length of the total flower and has 5 sharply pointed teeth at the tip, two of which are much larger than the other three. The calyx and corolla are hairless. The corolla is typical of Pea family flowers. It has lobes that shade from white to cream. One lobe of the corolla turns upward forming the large banner petal. It has a notch at the top. The other petals consist of two narrow laterals that fold downward and forward and then two joined keel petals within which are the reproductive parts of several stamens and a single style connected to the ovary. The corolla of fading flowers can turn orangish as a photo below shows.
Seed: Flowers are usually fertilized by long-tongued insects and mature to a linear seed pod resembling the garden pea, but flat. The pod splits into two sections at maturity to release fruit. Much like your typical garden pea pod. Seeds average 3.2 mm long by 2.8 mm wide and are flattened. A cool period is required to break dormancy. Fall planting will allow the climate to do the job.
Habitat: Cream Pea usually grows in dry sandy to loamy soils of uplands, wood edges, cliffs and other areas where full to partial sun is available. Like most peas, if it grows in too much shade, flower production will be reduced. It is a nitrogen fixing legume that grows in the cooler northern continental and boreal temperate climate.
Names: The genus Lathyrus, is from the Greek word lathyros, meaning 'pea'. The species ochroleucus, means 'yellowish-white', referring the cream color of the corolla. The author name for the plant classification - ‘Hook.’ is for William Hooker, (1785-1865), English Botanist, author, collector, Professor of Botany at the University of Glasgow and the first director of the Royal Botanic Garden at Kew. His work on North American plants was mostly published in Flora Boreali-Americana.
Comparisons: This is the only native pea of this genus that has white to cream colored flowers with broad leaflets and very large leaf stipules. Both Vicia americana, American Vetch, and Lathyrus palustris, Marsh Pea, also have a tendril at the tip, but the flowers are pink. Veiny Pea, Lathyrus venosus, also has a tendril at the leaf tip, but the leaflets are not opposite each other, and the flowers are pink.
Above: Cream Pea showing the inflorescence and the later leaf color. Note the large stipule. Drawing from Britton, N.L., and A. Brown. 1913. An illustrated flora of the northern United States, Canada and the British Possessions. 3 vols. Charles Scribner's Sons, New York.
Below: 1st photo - flowers showing a greenish-cream calyx and petals beginning to age. 2nd photo - Tendrils are at the end of the leaf.
Below: The calyx showing pinkish tinges. Note that 2 lobes of the calyx are larger. The flower facing downward is past maturity and showing typical orange cast.
Below: Leaves have 3 to 5+ pair of leaflets that have slightly asymmetrical bases; the tendril is at the tip of the leaf.
Below: 1st photo - the inflorescence is a stalked raceme of separately stalked flowers. 2nd photo - the large stipules. 3rd photo - the leaf underside is pale in color with a fine interlaced vein network.
Below: A group of plants in the Upland Garden.
Cream Pea is found across all of Canada except for some of the Maritime Provinces and in the U.S. is found in the northern states, from Washington State east as far south as Wyoming, Nebraska, Iowa, Illinois, Kentucky, Pennsylvania and New Jersey. Absent in most of New England. Lewis and Clark reported finding the plant on Jule 16, 1806 on the Lolo Trail in what is now Idaho.
In Minnesota Cream Pea is found in almost all counties of the State except those of the SW Quadrant. It is found throughout the metro area. There are six species of Lathyrus found in Minnesota: L. maritimus, Beach Pea; L. ochroleucus, Cream Pea or Pale Vetchling; L. palustris, Marsh Vetchling; and L. venosus, Veiny Pea are all considered native. Two others are introduced: L. latifolius, Everlasting Pea; and L. tuberosus, Tuberous Vetchling. Only L. venosus and L. ochroleucus are found in the Garden.
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"