Sisyrinchium atlanticum E.P. Bicknell

Eastern Blue-Eyed Grass


CC = 9
CW = -3
MOC = 14
SRank = S2

© SRTurner

Family - Iridaceae

Habit - Perennial (?) forb with fibrous roots, lacking rhizomes.

Stems - Aerial stems ascending, to 45 cm, flattened, 1-3 mm wide, narrowly winged, often somewhat glaucous, appearing branched.

Sisyrinchium_atlanticum_stem.jpg Stem with narrow wings.

© SRTurner

Leaves - Basal or nearly so, few, linear, straplike, flattened, 1-4 mm wide, often somewhat glaucous.

Inflorescences - 1-4 per aerial stem, from slender stalks 3-15 cm long from the axils of leaflike bracts. Spathelike bracts of each inflorescence 1.3-2.2 cm long, green, sometimes purplish tinged, subequal at flowering time or the outer bract less than 1.5 times as long as the inner bract. Each inflorescence with two to several flowers, these on stalks 8-18 mm long.

Sisyrinchium_atlanticum_inflorescences.jpg Stalked inflorescences.

© SRTurner

Sisyrinchium_atlanticum_inflorescence1.jpg Inflorescence.

© SRTurner

Sisyrinchium_atlanticum_inflorescence2.jpg Inflorescence.

© SRTurner

Flowers - Perianth 5-12 mm long, spreading, blue or purplish blue, usually with a well-developed white or light yellow "eye" at the base, the sepals and petals similar and fused at the bases, oblanceolate with the tips abruptly narrowed into an attenuate tip, sometimes with the attenuation protruding from an apical notch. Styles with 3 linear lobes. Stamens with the filaments fused to the tips or nearly so.

Sisyrinchium_atlanticum_flower2.jpg Flower.

© SRTurner

Sisyrinchium_atlanticum_flower.jpg Flower.

© SRTurner

Sisyrinchium_atlanticum_corollas.jpg Corollas.

© SRTurner

Fruits - Capsules 2-6 mm long, globose. Seeds black, globose.

Flowering - April - June.

Habitat - Prairies, pond margins, forest openings, cemeteries, roadsides, usually on sandy substrates.

Origin - Native to the U.S.

Lookalikes - Other species of Sisyrinchium, especially S. angustifolium.

Other info. - This little plant occurs in Missouri mostly in a few far-southern counties. Its main range is eastern, extending in a broad band along the Gulf and East Coasts. The blue-eyed grasses are generically recognized by their basal, grasslike leaves and small, blue flowers arising from a pair of bracts resembling a crab's claw. S. atlanticum is recognized by its stalked inflorescences (which lend a branching appearance to the overall habit), inflorescence bracts which are nearly the same length, and stems which are only very narrowly winged. However, Sisyrinchium is usually considered a taxonomically difficult group, with morphological variability and controversial species delineations contributing ambiguity. Determinations often require parts of plants which are sometimes not collected, such as roots and rhizomes, or may rely partially on color changes which occur during drying. Accepted species ranges may be influenced by differing taxonomic interpretations. It is not out of the question that the photos above could actually represent Sisyrinchium langloisii, which is common in Arkansas.

Despite their common names and grass-like leaves, plants in the Sisyrinchium genus are not grasses.

Photographs taken at Tingler Prairie Natural Area, Howell County, MO, 6-11-2021 (SRTurner).