Micranthemum micranthemoides

(Nuttall) Wettstein in H. G. A. Engler and K. Prantl

Nat. Pflanzenfam. 67[IV,3b]: 77. 1891.

Common names: Nuttall's mudflower
Endemic
Basionyms: Hemianthus micranthemoides Nuttall J. Acad. Nat. Sci. Philadelphia 1: 119, plate 6, fig. 2. 1817
Treatment appears in FNA Volume 17. Treatment on page 359. Mentioned on page 358.

Leaves opposite or whorled; petiole 0–0.5 mm; blade elliptic to oblanceolate, 3–6 × 1.2–3 mm. Pedicels 0.6–2 mm. Flowers cleistogamous; calyx irregularly symmetric, tube deeply lobed abaxially, 1.2–1.5 mm, tube 0.7–1 mm, lobes 0.5–0.6 mm; corolla strongly bilaterally symmetric, unilabiate or nearly so, 1.8–2 mm, longer than calyx, tube 0.3–0.5 mm, abaxial lobes 3, forming a prominent lip, 1.4–1.5 mm, lateral 0, adaxial (0–) 0.4–0.6 mm. Capsules 1.1–1.3 × 0.9–1 mm. Seeds oblong to narrowly obconic, 0.3–0.4 × 0.2–0.3 mm.


Phenology: Flowering summer–fall.
Habitat: Fresh water tidal areas in sandy, gravelly substrates.
Elevation: 0–10 m.

Distribution

Del., D.C., Md., N.J., N.Y., Pa., Va.

Discussion

The range given for Micranthemum micranthemoides is historic; it is presumed extinct in the wild but may still be available in the aquarium plant trade. The most recently collected specimen examined by the author was gathered in 1941 by M. L. Fernald (Fernald & Long 13754, GH) along the Chickahominy River near Cypress Bank Landing, Virginia.

Micranthemum nuttallii A. Gray is an older, but illegitimate name that pertains here; it was an avowed substitute for Hemianthus micranthemoides.

Selected References

None.

Lower Taxa

None.

0.14 cm1.4 mm <br />0.0014 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
0 cm0 mm <br />0 m <br /> (0.04 cm0.4 mm <br />4.0e-4 m <br />) +
0.04 cm0.4 mm <br />4.0e-4 m <br /> (0.06 cm0.6 mm <br />6.0e-4 m <br />) +
Brian R. Keener +
(Nuttall) Wettstein in H. G. A. Engler and K. Prantl +
Hemianthus micranthemoides +
0.3 cm3 mm <br />0.003 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
elliptic +  and oblanceolate +
not leathery +
1.2mm;3mm +
campanulate +
0.11 cm1.1 mm <br />0.0011 m <br /> (0.13 cm1.3 mm <br />0.0013 m <br />) +
0.09 cm0.9 mm <br />9.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
Nuttall's mudflower +
nearly +  and unilabiate +
0.18 cm1.8 mm <br />0.0018 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
Del. +, D.C. +, Md. +, N.J. +, N.Y. +, Pa. +  and Va. +
0–10 m. +
bearing a process +  and gibbous +
cleistogamous +
poricidal +  and septicidal +
Fresh water tidal areas in sandy, gravelly substrates. +
whorled +  and opposite +
prominent +
oblanceolate;lanceolate +
unequal +
toothed +, undulate +  and entire +
tenuinucellate +  and unitegmic +
orthotropous +
0.06 cm0.6 mm <br />6.0e-4 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
0 cm0 mm <br />0 m <br /> (0.05 cm0.5 mm <br />5.0e-4 m <br />) +
Flowering summer–fall. +
Nat. Pflanzenfam. +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.04 cm0.4 mm <br />4.0e-4 m <br />) +
oblong +  and narrowly obconic +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.03 cm0.3 mm <br />3.0e-4 m <br />) +
repent +  and prostrate +
prostrate +  and weakly ascending +
weakly +  and 4-angled +
neither +, clavate +, capitate +  and 2-lobed +
Hemianthus +
Micranthemum micranthemoides +
Micranthemum +
species +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.05 cm0.5 mm <br />5.0e-4 m <br />) +
perennial +  and annual +