Houstonia minima Beck - Bluets

Houstonia minima plant

Family - Rubiaceae

Stems - From small taproot, +/-4cm tall, erect, herbaceous, 4-angled, scabrous, strigillose on angles, hollow, multiple from base, dichotomously branching.

Leaves - Basal leaves petiolate, opposite. Petioles to +/-5mm long, glabrous. Blades broadly ovate, entire, glabrous, 4-5mm long, 3.5-4mm broad, rounded to subacute at apex. Cauline leaves reduced, opposite, becoming sessile, connected at base by scarious acuminate stipules(to 2mm long), acute, with some purplish tinge, slightly scabrous.

Houstonia minima leaves

Inflorescence - Singe terminal flowers. Peduncles to 1.3cm long, 4-angled, erect, scabrous as stems.

Flowers - Corolla salverform. Corolla tube 3mm long, glabrous. Corolla lobes 4, white to lilac or deep purple, broadly ovate, acute, to 4mm long, 2.5-3mm broad, entire, typically with a darker base. Stamens 4, included, adnate at middle of corolla tube. Filaments short, green, glabrous, .3mm long. Anthers yellow, .6mm long. Style -1mm long, green, glabrous. Stigma .7mm long, pubescent, ellipsoid. Ovary 2 locular, inferior. Placentation axile. Ovules many. Calyx tube +/-1mm long, glabrous. Lobes 4, linear-lanceolate, acute to acuminate, green with purple at margins, glabrous or strigillose, strigillose on margins.

Houstonia minima calyx

Houstonia minima flower

Flowering - January - April.

Habitat - Prairies, glades, flood plains, ledges, bluffs.

Origin - Native to U.S.

Other info. - This minute plant packs quite a punch of color for its size. My pictures don't really do the plant justice as the flowers are typically much more blue in color. The plant is quite prolific and can be found in large colonies, especially in the glade habitat. A rock garden could be enhanced greatly by the addition of this species.
This species and another, H. pusilla Schoepf, have been lumped together taxonomically and are now known as Hedyotis crassifolia Raf.

Photographs taken at Dave Rock Conservation Area, St. Clair County, MO., 4-2-01.


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