Nemastylis geminiflora Nutt.

Prairie Iris


CC = 10
CW = 5
MOC = 10
SRank = S2

© SRTurner

Family - Iridaceae

Habit - Perennial forb with ovoid or subglobose bulbs.

Stems - Ascending to erect, to 40 cm, terete.

Leaves - 1-3 per aerial stem, linear, to 11 mm wide, parallel veined, folded longitudinally near base, becoming pleated along veins or flat toward tips.

Nemastylis_geminiflora_leaves.jpg Leaves.

© SRTurner

Nemastylis_geminiflora_leaves2.jpg Leaves.

© SRTurner

Inflorescences - 1-3 per aerial stem from upper leaf axils, long stalked, each with 1-2 flowers enclosed by a pair of herbaceous spathelike bracts.

Nemastylis_geminiflora_bracts.jpg Inflorescence bracts.

© SRTurner

Nemastylis_geminiflora_twin.jpg Inflorescence.

Geminiflora="twin flowers," though this is not always seen.

© SRTurner

Flowers - On stalks 12-35 mm long. Perianth spreading, light blue to bright blue, usually with a well-developed white or light yellow "eye" at the base, the sepals and petals similar and fused at the bases, elliptic with the tips rounded or bluntly pointed, the petals slightly shorter than the sepals. Stamens 3, the filaments free or fused only at the base, the anthers 0.6-1.2 cm long, becoming tightly spirally twisted after shedding the pollen. Style short, deeply 3-lobed, each lobe again deeply 2-lobed, linear.

Nemastylis_geminiflora_corolla1.jpg Perianth.

© SRTurner

Nemastylis_geminiflora_corolla3.jpg Perianth.

© SRTurner

Nemastylis_geminiflora_anthers1.jpg Freshly opened flower. Anthers are long and straight.

© SRTurner

Nemastylis_geminiflora_corolla2.jpg Appearance of anthers following dehiscence.

© SRTurner

Fruits - Capsules 10-20 mm long, obovoid, tapering at the base, abruptly and broadly rounded or flattened at the tip. Seeds 2.0-2.5 mm long, broadly obovoid-angular, tapering to a short, beaklike tip at 1 end, dark brown.

Nemastylis_geminiflora_fruits.jpg Fruits.

© SRTurner

Flowering - April - May.

Habitat - Glades and prairies on calcareous substrate.

Origin - Native to the U.S.

Lookalikes - N. nuttallii.

Other info. - This plant has got to be one of the most strikingly beautiful of all Missouri's wildflowers. The three bright yellow anthers provide an attractive contrast to the delicate blue of the perianth. At the right place and time, the ground will be carpeted with hundreds of these bloom, but they don't last long. The plant is not common in Missouri, known from only a few widely scattered counties, and is considered imperiled in the state. Beyond Missouri its range extends to only a few other states, mostly to the south.

The specific epithet geminiflora means "twin flowers." Although the inflorescences do indeed often contain two flowers, it is less common for both to be open at the same time.

Photographs taken at St. Joe State Park, St. Francois County, MO, 5-2-2010, 5-31-2010, 4-26-2014, 4-10-2017, and 4-26-2020, and at St. Francois State Park, St. Francois County, MO, 5-5-2010 (SRTurner).