Myosotis macrosperma Engelm.

Myosotis macrosperma plant

Family - Boraginaceae

Stems - From a taproot and fibrous roots, multiple from the base, erect, herbaceous, green, hirsute, slightly angled from decurrent leaf tissue, to 50cm tall (in fruit), branching.

Myosotis macrosperma stem

Leaves - Alternate. Basal leaves spatulate, to +/-6cm long, -2cm broad. Cauline leaves sessile, oblong to oblong-lanceolate, to 6cm long, 1.5cm broad. All leaves entire, hirsute, acute to rounded at the apex, green, with a single distinct midrib. Faint lateral venation anastomosing before the leaf margin.

Myosotis macrosperma leaves

Inflorescence - Terminal and lateral scorpoid racemes or cymes, compact in flower, very elongated in fruit. Pedicels short in flower, elongating to 3-4mm long in fruit, lanate. Axis of inflorescence lanate.

Myosotis macrosperma inflorescenceInflorescence...

Myosotis macrosperma inflorescence...qickly elongating in fruit.

Flowers - Corolla white, funnelform, glabrous, slightly zygomorphic, 3mm broad, 3mm long, 5-lobed. Longest lobes to 1.2mm long, 1mm broad, truncate at apex. Fornices small, included in the throat of the corolla. Stamens 5, adnate above the base of the corolla tube. Filaments minute, -.1mm long. Anthers brownish, .5mm long. Ovary 4-lobed, subtended by a green nectary. Lobes green, glabrous, lenticular, to .3mm in diameter, with a slightly winged margin, expanding to +2mm in diameter in fruit. Style exserted from between ovary lobes, green, .7mm long, glabrous, included. Stigma bilobed. Calyx accrescent, densely uncinate pubescent (hirsute) externally, glabrous internally, 5-lobed, zygomorphic. Lobes attenuate, the longest to 2mm in flower (longer in fruit). Calyx tube to 2mm long in flower, longer in fruit.

Myosotis macrosperma flowersFlowers close-up.

Flowering - April - May.

Habitat - Fallow and cultivated fields, moist to dry woods, slopes, bottoms, roadsides, railroads.

Origin - Native to U.S.

Other info. - This species can be found throughout Missouri. The plant can be identified by its small white flowers, hirsute stems, and elongated inflorescences (in fruit).
Steyermark listed this species as a variety of M. virginica (L.) BSP. More modern taxonomy lumps M. virginica and M. macrosperma into the same species, M. verna Nutt. Regardless of what you call the plant, its annoying fruits will stick to your clothes and hair and are a chore to remove.

Photographs taken off Hwy 29, Guilford County, MO., 4-20-03.


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