Potentilla effusa

Douglas ex Lehmann

Nov. Stirp. Pug. 2: 8. 1830.

EndemicIllustrated
Synonyms: Potentilla hippiana subsp. effusa (Douglas ex Lehmann) Dorn P. hippiana var. effusa (Douglas ex Lehmann) Dorn
Treatment appears in FNA Volume 9. Treatment on page 162. Mentioned on page 161, 163.

Stems (0.5–) 1.5–4 (–5.5) dm, lengths 2–3 (–4) times basal leaves. Basal leaves pinnate, (3–) 5–15 (–25) cm; petiole 0.5–5 (–8) cm, long hairs absent to abundant, ± appressed, 1–3 mm, stiff to weak, short and crisped hairs absent or obscured, cottony hairs abundant (at least on first-formed leaves), glands sparse or obscured; leaflets not conduplicate, lateral ones evenly to unevenly paired, 2–5 (–7) per side (secondary leaflets sometimes interspersed) on distal 1/3–1/2 of leaf axis, distal pairs usually not decurrent or confluent with terminal leaflet, larger leaflets oblanceolate to narrowly obovate, 1–2.5 (–3) × 0.3–1.3 (–1.8) cm, distal (1/2–) 2/3–3/4 (rarely more) of margin incised ± 1/2 to midvein, teeth (1–) 2–9 per side, 1–4 mm, surfaces similar, gray to white or ± green, abaxial: long hairs sparse to common (at least on veins), 0.5–1.5 mm, weak to stiff, short or crisped hairs absent or sparse, sometimes obscured, cottony hairs absent or sparse to dense, glands absent, sparse, or obscured, adaxial: long hairs absent or sparse to common, short or crisped hairs absent or sparse, cottony hairs absent or sparse to abundant, glands absent or sparse. Cauline leaves 2–6+. Inflorescences 7–30-flowered. Pedicels 0.3–3 cm. Flowers: epicalyx bractlets linear to narrowly lanceolate, 1–2.5 (–3) × 0.3–1 mm, 1/2–2/3 as long as sepals, abaxial vestiture often much sparser than sepals, often glabrate or glabrescent distally, straight hairs absent or sparse, cottony hairs usually abundant (at least proximally), sometimes absent or nearly so (var. rupincola); hypanthium 2–6 mm diam.; sepals 3–6 (–7) mm, apex long acuminate; petals 4–6.5 × 4–6 mm; filaments 1–3.5 mm, anthers 0.5–1 mm; carpels 3–15, styles 1.5–2.1 mm. Achenes 1.8–2.1 mm, smooth.

Distribution

V9 236-distribution-map.jpg

Alta., Man., Sask., Colo., Idaho, Minn., Mont., N.Dak., N.Mex., Nebr., S.Dak., Utah, Wyo.

Discussion

Varieties 2 (2 in the flora).

In the southern Rocky Mountains, Potentilla effusa is relatively distinct from P. hippiana both morphologically and geographically, with P. effusa mostly east of the Continental Divide and P. hippiana mostly west. In general, P. hippiana differs from P. effusa in having leaflets more evenly paired, more tightly serrate with teeth often occurring on the whole margin, and more bicolored with abaxial vestiture of crisped rather than cottony hairs. Stems of P. effusa have more cauline leaves on average than P. hippiana, and vestiture of epicalyx bractlets of P. effusa (as here circumscribed) is never sericeous.

The distinction between the two species is marred by intermediate populations throughout their shared range in the northern Rocky Mountains and Great Plains. Most regional floras focused on these areas have accordingly included Potentilla effusa within P. hippiana, sometimes without infraspecific distinction. An alternate solution has been the recognition of P. hippiana subsp. effusa, with the subspecies further subdivided into the two varieties recognized here. The varieties themselves intergrade; P. effusa var. ×coloradensis (Rydberg) Th. Wolf is available for the hybrid.

Selected References

None.

Key

1 Leaflets gray to white, surfaces moderately long-hairy and moderately to densely cottony. Potentilla effusa var. effusa
1 Leaflets ± green, surfaces glabrous or sparsely to moderately long-hairy (at least on veins) and not or sparsely cottony. Potentilla effusa var. rupincola

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

... more about "Potentilla effusa"
white +  and more or less green +
glabrescent +  and glabrate +
smooth +  and slightly rugose +
1.8mm +  and 2.1mm +
green +  and white +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
Barbara Ertter +  and James L. Reveal +
Douglas ex Lehmann +
compound +  and simple +
15 cm150 mm <br />0.15 m <br /> (25 cm250 mm <br />0.25 m <br />) +
5 cm50 mm <br />0.05 m <br /> (15 cm150 mm <br />0.15 m <br />) +
Leucophyllae +
25 cm250 mm <br />0.25 m <br /> (30 cm300 mm <br />0.3 m <br />) +
less cordate or reniform +  and narrowly elliptic +
0.5 cm5 mm <br />0.005 m <br /> (25 cm250 mm <br />0.25 m <br />) +
reduced +
free +  and distinct +
hairy +  and glabrous +
Alta. +, Man. +, Sask. +, Colo. +, Idaho +, Minn. +, Mont. +, N.Dak. +, N.Mex. +, Nebr. +, S.Dak. +, Utah +  and Wyo. +
not +  and aggregated +
0.25 cm2.5 mm <br />0.0025 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
0.1 cm1 mm <br />0.001 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
linear +  and narrowly lanceolate +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
0.1 cm1 mm <br />0.001 m <br /> (0.35 cm3.5 mm <br />0.0035 m <br />) +
0.8 cm8 mm <br />0.008 m <br /> (2 cm20 mm <br />0.02 m <br />) +
unisexual +  and bisexual +
not +  and aggregated +
deciduous +
on style scar +, hairy +  and glabrous +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.26 cm2.6 mm <br />0.0026 m <br />) +
weak +  and stiff +
stoloniferous +  and short-rhizomatous +
straight +
weak +  and stiff +
nearly +, abundant +  and sparse +
crisped +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
0.25 cm2.5 mm <br />0.0025 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
0.7 cm7 mm <br />0.007 m <br /> (1 cm10 mm <br />0.01 m <br />) +
0.2 cm2 mm <br />0.002 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
0.2 cm2 mm <br />0.002 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
crassinucellate +
2.5 cm25 mm <br />0.025 m <br /> (3 cm30 mm <br />0.03 m <br />) +
1.3 cm13 mm <br />0.013 m <br /> (1.8 cm18 mm <br />0.018 m <br />) +
1 cm10 mm <br />0.01 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
0.3 cm3 mm <br />0.003 m <br /> (1.3 cm13 mm <br />0.013 m <br />) +
bipinnate +, odd-pinnate +, subpalmate +, palmate +  and ternate +
opposite +  and alternate +
marcescent +
well-developed +
persistent +
cauline +  and basal +
reduced +
oblanceolate +  and narrowly obovate oblong or cuneate +
linear +  and oblanceolate +
palmate +  and pinnate +
less +, 1/4 +  and 1/2 +
inferior +  and superior +
clustered +, biseriate +  and superposed +
3 cm30 mm <br />0.03 m <br /> (6 cm60 mm <br />0.06 m <br />) +
0.3 cm3 mm <br />0.003 m <br /> (3 cm30 mm <br />0.03 m <br />) +
0.3 cm3 mm <br />0.003 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
free +  and distinct +
0.4 cm4 mm <br />0.004 m <br /> (0.65 cm6.5 mm <br />0.0065 m <br />) +
usually longer +
0.4 cm4 mm <br />0.004 m <br /> (1 cm10 mm <br />0.01 m <br />) +
0.4 cm4 mm <br />0.004 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
5 cm50 mm <br />0.05 m <br /> (8 cm80 mm <br />0.08 m <br />) +
0.5 cm5 mm <br />0.005 m <br /> (5 cm50 mm <br />0.05 m <br />) +
adnate +, free +, connate +  and distinct +
pinnate +  and subpinnate +
45 cm450 mm <br />0.45 m <br /> (50 cm500 mm <br />0.5 m <br />) +
3 cm30 mm <br />0.03 m <br /> (45 cm450 mm <br />0.45 m <br />) +
Nov. Stirp. Pug. +
not arillate +
0.6 cm6 mm <br />0.006 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
persistent +
free +  and distinct +
erect +  and spreading +
lanceolate +  and broadly ovate or deltate +
0.3 cm3 mm <br />0.003 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
Endemic +  and Illustrated +
free +  and distinct +
not rooting +
reddish +  and green +
2-3(-4) times basal leaves +
ascending +  and erect +
1 +  and many +
not flagelliform +
palmate +  and pinnate +
0.1 cm1 mm <br />0.001 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
deciduous +
distinct +
subapical +
papillate-swollen +  and tapered-filiform +
rough-thickened +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.21 cm2.1 mm <br />0.0021 m <br />) +
gray +  and white or more or less green +
Potentilla hippiana subsp. effusa +  and P. hippiana var. effusa +
not fleshy-thickened +
Potentilla effusa +
Potentilla sect. Leucophyllae +
species +
2 +  and 9 +
0.1 cm1 mm <br />0.001 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
inconspicuous +
enlarged +
biennial +, annual +  and perennial +
herb +  and matted +