Diapensia obovata

(F. Schmidt) Nakai

Trees Shrubs Japan 1: 194. 1922 ,.

Common names: Alaskan pincushion plant
Basionym: Diapensia lapponica var. obovata F. Schmidt Mém. Acad. Imp. Sci. Saint Pétersbourg, Sér. 7, 12: 161. 1868
Synonyms: Diapensia lapponica subsp. obovata (F. Schmidt) Hultén
Treatment appears in FNA Volume 8. Treatment on page 338. Mentioned on page 332.

Plants usually forming mats or low mounds or cushions (not tussock-forming), 2–5 cm; branches procumbent or decumbent, adventitiously rooted, proximal portions of stems with or without persistent leaf remnants. Leaves 3–8 (–12) mm; blade obovate to spatulate-elliptic, 1.5–2.2 (–3) mm wide, margins narrowly revolute, usually herbaceous, sometimes with narrow hyaline flange. Pedicels 5–20 mm, elongating to 30–50 mm. Flowers: sepals 4–7 mm; corolla 7–9 mm, lobes usually white, sometimes light pink or rose. Capsules 3–4 (–6) mm diam. 2n = 12.


Phenology: Flowering Jun–Jul.
Habitat: Tundra, alpine heath, subalpine meadows, slopes and ridges, dry or moist areas, gravel, silt (run-off banks)
Elevation: 500-1500 m

Distribution

V8 668-distribution-map.gif

B.C., N.W.T., Yukon, Alaska, Asia (Japan), Asia (Korea), Asia (Russia [Kamchatka]), Asia (e arctic and subarctic Siberia)

Discussion

Justifying his recognition of Diapensia obovata at subspecific rank, E. Hultén (1941–1950, vol. 8) wrote that “it seems to me to be a clear geographical race of D. lapponica and should be regarded as a subspecies.” Among relatively recent accounts to include both taxa, Hultén (1968), H. J. Scoggan (1978–1979, part 4), and W. J. Cody (2000) treated them as subspecies; B. K. Schischkin (1952) and A. E. Porsild and W. J. Cody (1980) treated them as distinct species.

The two taxa differ consistently in morphology, especially in growth form. In leaf shape, they are generally distinct, although their ranges of variation overlap. P. J. Scott and R. T. Day (1983) observed that they differ significantly in leaf length/width ratio—2–2.5 in subsp. lapponica versus 2.75–2.8 in subsp. obovata—but that the “distinction between the subspecies breaks down where they nearly meet in the Northwest Territories of Canada.” Maps by E. Hultén (1968) and A. E. Porsild and W. J. Cody (1980) indicate that the two taxa are separated in range by about 1000 kilometers. Each in its characteristic form is distributed over a broad area, and, in the view here, meets the morphogeographic criteria generally used for plant species.

Selected References

None.

Lower Taxa

None.
... more about "Diapensia obovata"
Guy L. Nesom +
(F. Schmidt) Nakai +
Diapensia lapponica var. obovata +
dentate-serrate +  and entire +
obovate;spatulate-elliptic +
1.5mm;2.2mm +
decumbent +  and procumbent +
0.3 cm3 mm <br />0.003 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
Alaskan pincushion plant +
0.7 cm7 mm <br />0.007 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
B.C. +, N.W.T. +, Yukon +, Alaska +, Asia (Japan) +, Asia (Korea) +, Asia (Russia [Kamchatka]) +  and Asia (e arctic and subarctic Siberia) +
500-1500 m +
straight;curved +
loculicidal +
Tundra, alpine heath, subalpine meadows, slopes and ridges, dry or moist areas, gravel, silt (run-off banks) +
pedicellate +  and subsessile +
crowded +, imbricate +, whorled +  and opposite +
0.8 cm8 mm <br />0.008 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
0.3 cm3 mm <br />0.003 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
rose +, light pink +  and white +
tenuinucellate +, bitegmic +  and hemitropous +
amphitropous +, campylotropous +  and anatropous +
elongating +
3 cm30 mm <br />0.03 m <br /> (5 cm50 mm <br />0.05 m <br />) +
Flowering Jun–Jul. +
Trees Shrubs Japan +
cylindric +
connate +  and distinct +
0.4 cm4 mm <br />0.004 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
epipetalous +  and antisepalous +
spatulate +  and scale-like +
mostly prostrate +  and decumbent +
slightly 3-lobed;unlobed +
Diapensia lapponica subsp. obovata +
Diapensia obovata +
Diapensia +
species +
taprooted +  and caulescent +
evergreen +  and perennial +
cushion +  and plant +