Petrophytum hendersonii

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

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

Common names: Olympic mountain rockmat
Endemic
Basionym: Eriogynia hendersonii Canby Bot. Gaz. 16: 236. 1891 (as hendersoni)
Synonyms: Luetkea hendersonii (Canby) Greene Spiraea hendersonii (Canby) Piper
Treatment appears in FNA Volume 9. Treatment on page 412. Mentioned on page 411, 413.

Shrubs, 2–9 dm diam. Stems decumbent to ascending, 1–10 cm, internodes 0.5–1.5 cm. Leaves: blade narrowly obtrullate, sometimes oblanceolate to spatulate-obovate, 1–2 (–3) × 0.2–0.6 cm, palmately 3-veined, venation visible through hairs, apex acute, abaxial surface sparsely strigose, pilose to pilose-sericeous, sometimes glabrate, sparsely strigose along veins. Panicles densely racemose, 2–5 × 1–2 cm, sparsely sericeous; bracts linear, 2–4 (–6) mm, pilose. Pedicels 2–5 mm; bracteoles 1, rarely extending to base of sepals. Flowers 3–5 mm diam.; hypanthium 0.5–1 mm, sparsely pilose; sepals reflexed, oblong to obtuse, 1–1.5 mm, margins ciliate, abaxial surface sparsely pilose; petals oval, oblong, or obovate, 2–2.5 mm, apex obtuse, sometimes 2-lobate; stamens 25–40, lengths 1–1.3 times petals (2 times sepals); carpels (4–) 5 (–6), abaxially connate. Follicles 1.5–2 mm. 2n = 18.


Phenology: Flowering Jul–Sep.
Habitat: Rock outcrops, cliffs, talus slopes
Elevation: 1000–2300 m

Discussion

Petrophytum hendersonii is known only from the Olympic Mountains of northwestern Washington.

Selected References

None.

Lower Taxa

None.

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

... more about "Petrophytum hendersonii"
pilose +, strigose +, glabrate +  and pilose-sericeous +
Richard Lis +
(Canby) Rydberg in N. L. Britton et al. +
gray +, brown +  and dark-brown +
compound +  and simple +
opposite +  and alternate +
Eriogynia hendersonii +
2 cm20 mm <br />0.02 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 />) +
1 cm10 mm <br />0.01 m <br /> (2 cm20 mm <br />0.02 m <br />) +
oblanceolate +  and spatulate-obovate +
0.2 cm2 mm <br />0.002 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
0.2cm +  and 0.6cm +
0.4 cm4 mm <br />0.004 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
2mm +  and 4mm +
hirsute +  and pilose +
Olympic mountain rockmat +
not +  and aggregated +
1000–2300 m +
0.3 cm3 mm <br />0.003 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
canescent +  and sericeous +
unisexual +  and bisexual +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.2 cm2 mm <br />0.002 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 +
Rock outcrops, cliffs, talus slopes +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
crassinucellate +
0.5 cm5 mm <br />0.005 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
compound +  and simple +
marcescent +
persistent +
entire +  and crenulate +
inferior +  and superior +
biseriate +  and clustered +
collateral +  and apical +
3 +  and 2 +
2cm +  and 5cm +
1 cm10 mm <br />0.01 m <br /> (2 cm20 mm <br />0.02 m <br />) +
0.2 cm2 mm <br />0.002 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
0 (?) +  and 4 (?) +
persistent +
free +  and distinct +
0.2 cm2 mm <br />0.002 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
Flowering Jul–Sep. +
adnate +, free +, connate +  and distinct +
in N. L. Britton et al., N. Amer. Fl. +
not arillate +
list;count +
persistent +
free +  and distinct +
oblong +  and obtuse +
0.1 cm1 mm <br />0.001 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
free +  and distinct +
1-1.3 times petals +
branched +  and simple +
decumbent +  and ascending +
1 cm10 mm <br />0.01 m <br /> (10 cm100 mm <br />0.1 m <br />) +
persistent +  and deciduous +
distinct +
basal +, lateral +, subterminal +  and terminal +
not elongate +
sericeous +, pilose +, canescent +, strigose +  and glabrate +
Luetkea hendersonii +  and Spiraea hendersonii +
Petrophytum hendersonii +
Petrophytum +
species +
inconspicuous +
thickened +  and minute +