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Vascular Plants of California
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Salix petrophila

ROCKY MOUNTAIN WILLOW


Higher Taxonomy
Family: SalicaceaeView DescriptionDichotomous Key
Common Name: WILLOW FAMILY
Habit: Shrub, tree; dioecious (monoecious). Stem: trunk < 40 m; wood soft; bark smooth, bitter; buds scaly. Leaf: simple, alternate, deciduous; stipules generally present, deciduous or not, often large. Inflorescence: catkin [or various, or flowers 1]; each flower subtended by 1 bract. Flower: perianth modified into non-nectariferous, cup- or saucer-shaped structure or reduced to adaxial nectary (rarely also with abaxial nectary, then free or fused into shallow cup). Staminate Flower: stamens 2--many. Pistillate Flower: pistil 1, ovary superior to 1/2-inferior, chambers generally 2--4, placentas parietal, stigma lobes 2--4. Fruit: berry, drupe, or 2--4-valved capsule. Seed: often with basal tuft of hairs.
Genera In Family: 58 genera, 1210 species: widespread in tropics, northern temperate, arctic. Note: Now including many genera (e.g., Flacourtia, Idesia, Xylosma) formerly in Flacourtiaceae, at least in part because of presence on leaf margins in both families of salicoid teeth (vein extending to tooth tip). In California (and generally outside California), Populus pollinated by wind, Salix by insects, wind. Hybrids common; identification often difficult.
eFlora Treatment Author: John O. Sawyer, Jr., except as noted
Scientific Editor: Thomas J. Rosatti.
Genus: SalixView DescriptionDichotomous Key


Common Name: WILLOW
Habit: Shrub, tree; dioecious; bud scale 1, not sticky, margins generally fused (or free, overlapping). Stem: twigs generally flexible, generally not glaucous. Leaf: generally alternate; stipules generally vestigial on first leaves, leaf-like on later; mature blade linear to broadly obovate, entire to toothed, generally +- hairy; petiole glands generally 0. Inflorescence: catkin, blooming before, with, or after leaves, sessile or terminating +- short leafy or bracted shoot ("on leafy shoot" or "on bracted shoot," "catkin length" including leafless or bractless part of subtending shoot); 1 flower bract subtending each flower, deciduous or persistent, brown, black, or 2-colored (paler proximally, darker distally; darker generally +- brown). Flower: perianth reduced to adaxial nectary (rarely also with abaxial nectary, then free or fused into shallow cup). Staminate Flower: stamens (1)2(10); nectary generally 1. Pistillate Flower: ovary stalked or sessile, style generally 1, stigmas 2, each 2-lobed, deciduous or persistent; nectary generally 1, generally rod-like. Fruit: valves 2.
Etymology: (Latin: ancient name) Note: Difficult, highly variable, many hybrids. Not all specimens key easily; sprouts, other extreme forms not included in keys, may require field comparisons. Studies of chromosome numbers, hybridization needed. Inclusion of Salix sessilifolia Nutt. in TJM (1993) based on misidentification of plants belonging to Salix melanopsis. Fruit length as given throughout excludes the stalk (stipe). Hair lengths: minute, < +- 0.5 mm; short, +- 0.5 mm; long, > +- 0.5 mm. Salix commutata Bebb, treated as misapplied to Salix eastwoodiae in TJM (1993), may occur in northern California mountains; Salix bonplandiana expected in s-most California. For alternate treatments, see Dorn (e.g., 2000 Brittonia 52:1--19).
eFlora Treatment Author: George W. Argus
Reference: Argus 1997 Madroño 44:115--136
Unabridged Reference: Dorn, R. D. 1995. A taxonomic study of Salix section Cordatae subsection Luteae (Salicaceae). Brittonia 47: 160--174. Dorn, R. D. 1998. A taxonomic study of Salix section Longifoliae (Salicaceae) Brittonia 50: 193--210. Dorn, R. D. 2000. A taxonomic study of Salix sections Mexicanae and Viminella subsection Sitchenses (Salicaceae) in North America. Brittonia 52: 1--19.
Salix petrophila Rydb.
NATIVE
Habit: Shrub < 0.1 m, trailing, rooting. Stem: twigs yellow-green or -brown, sparsely soft-shaggy-hairy. Leaf: stipules 0 or vestigial; petiole 2--13 mm; young leaves long-soft-hairy; mature blade 19--44 mm, elliptic to obovate, acuminate to rounded (base wedge-shaped), entire, abaxial hairs long-soft-shaggy, wavy, to +- 0. Inflorescence: blooming with leaves, 18--60 mm, on leafy shoots 2--40 mm; flower bract +- tan to dark brown. Staminate Flower: stamens 2; nectaries generally only adaxial. Pistillate Flower: ovary silky, stalk 0.2--0.8 mm, style 0.4--1.6 mm. Chromosomes: 2n=76.
Ecology: Alpine tundra; Elevation: 1670--4000 m. Bioregional Distribution: CaRH (Lassen Peak), c&s SNH; Distribution Outside California: to western Canada, Colorado, New Mexico. Flowering Time: Jul--Aug Note: California, southern Rocky Mountains plants treated as part of Salix arctica Pall. in TJM (1993) treated here as a separate sp., Salix petrophila, elsewhere as Salix arctica subsp. petraea. Plants with narrow, sharp-pointed leaves approach Salix cascadensis Cockerell of Washington and northern, need study.
Synonyms: Salix arctica Pall., misappl.; Salix arctica subsp. petraea (Andersson) Á. Löve, D. Löve, & B.M. Kapoor
Jepson eFlora Author: George W. Argus
Reference: Argus 1997 Madroño 44:115--136
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)

Previous taxon: Salix orestera
Next taxon: Salix planifolia

Botanical illustration including Salix petrophilabotanical illustration including Salix petrophila


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Citation for this treatment: George W. Argus 2012, Salix petrophila, in Jepson Flora Project (eds.) Jepson eFlora, https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=42690, accessed on November 08, 2024.

Citation for the whole project: Jepson Flora Project (eds.) 2024, Jepson eFlora, https://ucjeps.berkeley.edu/eflora/, accessed on November 08, 2024.

Salix petrophila
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©2008 Neal Kramer
Salix petrophila
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©2013 Gary A. Monroe
Salix petrophila
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©2019 Neal Kramer
Salix petrophila
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©2008 Aaron Schusteff
Salix petrophila
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©2005 Steve Matson

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Geographic subdivisions for Salix petrophila:
CaRH (Lassen Peak), c&s SNH
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map of distribution 1

(Note: any qualifiers in the taxon distribution description, such as 'northern', 'southern', 'adjacent' etc., are not reflected in the map above, and in some cases indication of a taxon in a subdivision is based on a single collection or author-verified occurrence).






 

Data provided by the participants of the  Consortium of California Herbaria.

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CCH collections by month Flowering-Fruiting Monthly Counts

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa, if there are more than 1 infraspecific taxon in CA.
Blue line denotes eFlora flowering time (fruiting time in some monocot genera).