Petrophytum cinerascens

(Piper) Rydberg in N. L. Britton et al.

in N. L. Britton et al., N. Amer. Fl. 22: 253. 1908.

Common names: Chelan rockmat
Conservation concernEndemic
Basionym: Spiraea cinerascens Piper Erythea 7: 171. 1899
Synonyms: Luetkea cinerascens (Piper) A. Heller
Treatment appears in FNA Volume 9. Treatment on page 412. Mentioned on page 411, 413.

Shrubs, 1–5 dm diam. Stems prostrate to decumbent, 2–8 cm, internodes (0.1–) 1 (–2) cm. Leaves: blade oblanceolate to obtuse, 1–2.5 (–3) × 0.2–0.4 (–0.5) cm, palmately 3-veined, venation sometimes visible through hairs, apex obtuse, abaxial surface minutely canescent to strigose or cinereous, adaxial sometimes glandular. Panicles sometimes branched, 2–8 (–15) × 1–5 cm, canescent to puberulent; bracts linear to oblanceolate, 5–10 mm, pilose. Pedicels 0.5–2 (–4) mm; bracteoles 1 (–2), extending from middle to apex of sepals, rarely beyond. Flowers 2–4 (–6) mm diam.; hypanthium 1 mm, canescent; sepals erect, ovate or lanceolate, 1–1.5 mm, margins ciliate, abaxial surface pubescent, glandular; petals oblanceolate or narrowly ovate, 1–2.5 mm, apex acute or rounded; stamens 20–25, lengths 1.3 times petals (1.3–1.5 times sepals); carpels (3–) 5 (–6), distinct. Follicles 2 mm.


Phenology: Flowering Jun–Aug.
Habitat: Crevices and ledges of outcrops, gneiss, schist, or granite
Elevation: 200–600 m

Discussion

Of conservation concern.

Petrophytum cinerascens grows in crevices and ledges of outcrops above the Columbia River where there is little or no soil; it was found only on rocky outcrops of gneiss, schist, and granite between Chelan and Wenatchee in central Washington (D. J. Moore et al. 1998); C. L. Hitchcock et al. (1955–1969, vol. 3) erroneously cited its habitat as basaltic cliffs, which is the more common rock type on the Columbia River plateau. Moore et al. evaluated the ability of P. cinerascens for photosynthetic acclimation to increased growth temperature and drought stress under short-term experimental conditions, and concluded that it could not acclimate to such changes; they suggested that this endemic species might be at risk of extinction if warmer, drier local conditions result from projected climate changes.

Selected References

None.

Lower Taxa

None.

"dm" is not declared as a valid unit of measurement for this property.

... more about "Petrophytum cinerascens"
pubescent +, minutely canescent +  and strigose +
Richard Lis +
(Piper) Rydberg in N. L. Britton et al. +
gray +, brown +  and dark-brown +
compound +  and simple +
opposite +  and alternate +
Spiraea cinerascens +
2.5 cm25 mm <br />0.025 m <br /> (3 cm30 mm <br />0.03 m <br />) +
2.5 cm25 mm <br />0.025 m <br /> (3 cm30 mm <br />0.03 m <br />) +
0.4 cm4 mm <br />0.004 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
1 cm10 mm <br />0.01 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
oblanceolate +  and obtuse +
0.2 cm2 mm <br />0.002 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
0.2cm +  and 0.4cm +
linear +  and oblanceolate +
5mm +  and 10mm +
hirsute +  and pilose +
Chelan rockmat +
not +  and aggregated +
200–600 m +
0.2 cm2 mm <br />0.002 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
canescent +  and sericeous +
unisexual +  and bisexual +
2 cm20 mm <br />0.02 m <br /> (?) +
pilose +, glabrate +  and glabrous +
lanceoloid +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
coriaceous +
not +  and aggregated +
not +  and aggregated +
Crevices and ledges of outcrops, gneiss, schist, or granite +
1 cm10 mm <br />0.01 m <br /> (?) +
crassinucellate +
1 cm10 mm <br />0.01 m <br /> (2 cm20 mm <br />0.02 m <br />) +
1 cm10 mm <br />0.01 m <br /> (?) +
compound +  and simple +
marcescent +
persistent +
entire +  and crenulate +
inferior +  and superior +
biseriate +  and clustered +
collateral +  and apical +
3 +  and 2 +
8 cm80 mm <br />0.08 m <br /> (15 cm150 mm <br />0.15 m <br />) +
2cm +  and 8cm +
canescent +  and puberulent +
1 cm10 mm <br />0.01 m <br /> (5 cm50 mm <br />0.05 m <br />) +
0.2 cm2 mm <br />0.002 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
0 (?) +  and 4 (?) +
persistent +
free +  and distinct +
0.1 cm1 mm <br />0.001 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
Flowering Jun–Aug. +
adnate +, free +, connate +  and distinct +
in N. L. Britton et al., N. Amer. Fl. +
not arillate +
list;count +
persistent +
free +  and distinct +
lanceolate +  and ovate +
0.1 cm1 mm <br />0.001 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
Conservation concern +  and Endemic +
free +  and distinct +
1.3 times petals +
branched +  and simple +
prostrate +  and decumbent +
ascending +, erect +  and decumbent +
2 cm20 mm <br />0.02 m <br /> (8 cm80 mm <br />0.08 m <br />) +
persistent +  and deciduous +
distinct +
basal +, lateral +, subterminal +  and terminal +
not elongate +
sericeous +, pilose +, canescent +, strigose +  and glabrate +
Luetkea cinerascens +
Petrophytum cinerascens +
Petrophytum +
species +
inconspicuous +
thickened +  and minute +