Dryas octopetala

Linnaeus

Sp. Pl. 1: 501. 1753.

Endemic
Treatment appears in FNA Volume 9. Treatment on page 330. Mentioned on page 327, 328, 331.

Plants 2.5–12 cm. Leaf-blades oblong or ovate to elliptic, 3–16 × 0.5–6.5 mm, base usually truncate or cordate, sometimes cuneate, margins flat, coarsely dentate to serrate, sinuses 5–50 (–65) % to midvein, apex acute to rounded, surfaces plicate along midvein, usually rugulose, sometimes rugose, midvein and lateral-veins sunken, abaxial tomentose to woolly, adaxial usually glabrous, rarely tomentose or sparsely hairy proximally on midvein, feathery hairs scattered to rare along midveins abaxially and on petioles, scattered to rare elsewhere, midveins and petiole apices usually abaxially stipitate-glandular. Peduncles 11–125 mm. Flowers erect at flowering; sepals linear-oblong, 4–7 × 1.5–2.5 mm; petals 8, spreading, white or cream, 9–14 × 5–9 mm; filaments glabrous. Achenes 2.5–3 mm; styles 16–32 mm.


Phenology: Flowering Jun–Aug.
Habitat: Tundra
Elevation: 1000 m

Discussion

On Greenland, a major zone of hybridization and introgression of Dryas octopetala with D. integrifolia occurs, mixing morphological characteristics so extensively as to nearly obliterate D. octopetala (E. Hultén 1971). M. Phillip and H. R. Siegismund (2003) found continuous variation, making a clear separation of the two species impossible. N. Tremblay and D. Schoen (1999) described a series of events isolating populations of Dryas species in refugia during glaciation followed by secondary contact between species after glacial retreat; such events could explain the large amount of variability seen on much of Greenland. Such hybridization and diversification are not uncommon in arctic species (Phillip and Siegismund) and were too recent to allow fixation of consistent characteristics throughout the range of taxa (I. Nordal et al. 1999).

Phenotypically, some plants of the eastern coast of Greenland seem to be outliers of Dryas octopetala in the strict sense (T. T. Elkington 1965). Introgressed plants on Greenland have been called D. chamissonis Sprengel ex Juzepczuk (formerly D. chamissonis Jurtzev).

Selected References

None.

Lower Taxa

None.
... more about "Dryas octopetala"
tomentose +  and woolly +
2.5mm +  and 3mm +
hairy +, tomentose +  and glabrous +
Joshua C. Springer +  and Bruce D. Parfitt† +
Linnaeus +
blackish +, reddish +  and brown +
compound +  and simple +
opposite +  and alternate +
cuneate +, cordate +  and truncate +
3.9 cm39 mm <br />0.039 m <br /> (4.6 cm46 mm <br />0.046 m <br />) +
smooth +  and rugose +
ovate +, oval +, obovate +, oblongelliptic +, oblong +, linear +, lanceolate +  and elliptic +
0.2 cm2 mm <br />0.002 m <br /> (3.9 cm39 mm <br />0.039 m <br />) +
stoloniferous +
free +  and distinct +
Greenland +
not +  and aggregated +
1000 m +
stipitate-glandular +  and villous +
1.3 cm13 mm <br />0.013 m <br /> (2.9 cm29 mm <br />0.029 m <br />) +
unisexual +  and bisexual +
not +  and aggregated +
linear +  and lanceolate +
0.08 cm0.8 mm <br />8.0e-4 m <br /> (0.35 cm3.5 mm <br />0.0035 m <br />) +
Tundra +
0.3 cm3 mm <br />0.003 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
crassinucellate +
0.3 cm3 mm <br />0.003 m <br /> (1.6 cm16 mm <br />0.016 m <br />) +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.65 cm6.5 mm <br />0.0065 m <br />) +
persistent +
crenate +  and 1-2-toothed +
stipitate-glandular +
inferior +  and superior +
clustered +, biseriate +  and superposed +
1.1 cm11 mm <br />0.011 m <br /> (12.5 cm125 mm <br />0.125 m <br />) +
persistent +  and deciduous +
free +  and distinct +
0.9 cm9 mm <br />0.009 m <br /> (1.4 cm14 mm <br />0.014 m <br />) +
0.5 cm5 mm <br />0.005 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
Flowering Jun–Aug. +
adnate +, free +, connate +  and distinct +
not arillate +
persistent +
free +  and distinct +
erect-ascending +, ascending +  and spreading +
linear-oblong +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
free +  and distinct +
rooting +  and branched +
adnate +  and free +
persistent +
distinct +
basal +, lateral +, subterminal +  and terminal +
elongate +
1.6 cm16 mm <br />0.016 m <br /> (3.2 cm32 mm <br />0.032 m <br />) +
rugose +  and rugulose +
Dryas octopetala +
species +
inconspicuous +
hemispheric +