Grove Sandwort (Moehringia lateriflora)

Description: This perennial wildflower is 2-8" tall. It is ascending to erect with either unbranched or sparingly branched stems. The slender stems are light green, terete, and usually short-pubescent. There are pairs of opposite leaves at intervals along these stems. The leaves are ½-1¼" long and about one-third as much across; they are medium green, glabrous above, and either glabrous or short-pubescent below. The leaves are oblong-elliptic to broadly oblong-elliptic in shape and smooth along their margins; they are either sessile or have short petioles (1 mm. in length). The stems terminate in small clusters of 2-5 flowers (less often individual flowers). In addition, axillary clusters of flowers may originate from the upper two pairs of leaves. Individual flowers are up to 1/3" across (8 mm.), consisting of 5 white petals, 5 light green sepals, a light green superior ovary with 3 styles, and 10 stamens. The widely spreading petals are oblong-elliptic in shape and about twice as long as the sepals. The sepals are lanceolate to ovate with blunt tips and either glabrous or short-pubescent. The very slender pedicels are up to 1" long and usually short-pubescent. The blooming period occurs during late spring to early summer and lasts about 1 month. Afterwards, the flowers are replaced by ovoid seed capsules about ¼" long. Along the upper rim of a mature seed capsule, there are 6 recurved teeth. Each seed capsule contains only a few seeds that are about 1 mm. in length, reniform and somewhat flattened in shape, and smooth along their outer surfaces. Attached to each seed, there is a spongy food appendage (elaisome). The root system is fibrous and rhizomatous. Clonal offsets often develop from the rhizomes, forming small colonies of plants.

Cultivation: The preference is partial sun to light shade, moist to dry-mesic conditions, and soil that is loamy, gravelly, or sandy with decaying organic matter.

Range & Habitat: The native Grove Sandwort is uncommon in the northern half of Illinois, while in the southern half of the state it is absent (see Distribution Map). Illinois lies along the southern range limit of this species, which has a circumboreal distribution that includes North America, Europe, and Asia. Habitats consist primarily of open woodlands, sandy oak woodlands, woodland borders, and gravelly or rocky borders of streams in wooded areas. Less often, this wildflower occurs in meadows and prairies as an understory plant.

Faunal Associations: The nectar and pollen of the flowers probably attract small bees (Halictid, Andrenid) and flies (Syrphid). Otherwise, little is known about floral-faunal relationships for this species.

Photographic Location: The wildflower garden of the webmaster in Urbana, Illinois.

Comments: This is a delicate and attractive small wildflower that can be easily overlooked. Across local populations of plants, there is some variability in hairiness of the foliage and width of the leaves. Grove Sandwort can be distinguished from similar species in the Pink family by the shape of its leaves, the characteristics of its flowers, and the number of teeth of its seed capsules. Unlike chickweeds (both Stellaria spp. & Cerastium spp.), Grove Sandwort has petals that are neither notched at their tips nor deeply bifurcated. Its flowers are similar to those of Minuartia spp. (Sandworts), but it has wider leaves than the latter and its seed capsules have 6 teeth, instead of 3. Grove Sandwort is also similar to Arenaria serpyllifolia (Thyme-Leaved Sandwort), but its leaves are more long and narrow in shape. Grove Sandwort differs from all of these species by the food appendages (elaisomes) that are attached to its seeds. This is a highly unusual characteristic for a species in the Pink family. A scientific synonym of Grove Sandwort is Arenaria lateriflora.