Boechera fructicosa
Boechera pinetorum
Holboell's rock-cress, woodland rock-cress
3 to many per caudex branch, arising from margin of rosette near ground surface, 3.5–6 dm, pubescent proximally, trichomes short-stalked, 2–4-rayed, 0.2–0.3 mm, glabrous distally.
usually 1 per caudex branch, arising from center of rosette near ground surface, 2–8(–9.6) dm, densely pubescent proximally, trichomes simple and short-stalked, 2–4-rayed, to 1 mm, sparsely pubescent or glabrous distally.
blade oblanceolate, 3–7 mm wide, margins dentate, ciliate proximally, trichomes (simple), to 0.3 mm, surfaces pubescent, trichomes short-stalked, 4–8-rayed, 0.05–0.2 mm.
blade oblanceolate, 2–8(–11) mm wide, margins entire or denticulate, ciliate proximally, trichomes (simple), 0.5–1 mm, surfaces sparsely to densely pubescent, trichomes short-stalked, 2–4 (or 5)-rayed, 0.2–0.5 mm, these mixed with fewer simple ones.
5–10, not concealing stem;
blade auricles 0.5–1 mm, surfaces of distalmost leaves glabrous.
7–33, often concealing stem proximally;
blade auricles 1–3 mm, surfaces of distalmost leaves sparsely pubescent or glabrous.
10–18-flowered, usually unbranched.
15–63-flowered, usually unbranched.
divaricate-ascending at anthesis;
sepals pubescent;
petals lavender, 4–6 × 1–1.5 mm, glabrous;
pollen spheroid.
divaricate to pendent at anthesis;
sepals pubescent;
petals white to lavender, 5–6 × 1–1.5 mm, glabrous;
pollen spheroid.
divaricate-descending, straight, 5–10 mm, glabrous.
reflexed, abruptly recurved near base, otherwise straight, 4–12 mm, sparsely pubescent or glabrous, trichomes spreading, simple and 2-rayed.
divaricate-descending, not appressed to rachis, not secund, curved, edges parallel, 4–6 cm × 1.5–1.8 mm;
valves glabrous;
ovules 60–70 per ovary;
style 0.1–0.4 mm.
reflexed to closely pendent, not appressed to rachis, not secund, straight or curved, edges parallel, (4.5–)5.5–8.5 cm × 1.5–2 mm;
valves glabrous;
ovules 70–110 per ovary;
style 0.05–0.4 mm.
uniseriate, 1.5–2 × 1–1.3 mm;
wing distal, ca. 0.1 mm wide.
uniseriate, 1.5–1.8 × 1.2–1.5 mm;
wing continuous, 0.15–0.3 mm wide.
Boechera fructicosa
Boechera pinetorum
Boechera fructicosa is known only from the type collection (A. & E. Nelson 5681) taken near Undine Falls in Park County. Multiple plants are represented (comprising the holotype and four isotypes), though one specimen with the same number at RM is B. stricta. Although the exact parentage of this apomictic hybrid remains in doubt, it is virtually certain that B. microphylla contributed at least one genome.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Most authors (e.g., R. C. Rollins 1993; R. D. Dorn 2001; S. L. Welsh et al. 2003; N. H. Holmgren 2005b) have treated Boechera pinetorum as a variety of Arabis (Boechera) holboellii. Under this guise, the name has been applied to a vast array of plants collected throughout western North America. This includes a diversity of sexual diploids plus nearly every hybrid containing a genome from B. retrofracta. Based on re-examination of the type collection, we have adopted a much narrower concept of the species. Morphological evidence suggests that B. pinetorum is an apomictic triploid hybrid containing three different genomes, derived from B. rectissima, B. retrofracta, and B. sparsiflora. Plants closely resembling the type of B. pinetorum are confined to the northern Sierra Nevada and adjacent southern Cascades. The majority of collections previously associated with the epithet pinetorum represent B. pauciflora (see M. D. Windham and I. A. Al-Shehbaz 2007 for detailed comparison).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
- Local floras:
CA, 
OR - Local Web sites: CalFlora, CalPhotos,
Flora NW, 
PNW Herbaria 
WildflowerSearch
iNaturalist (observations)- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
