Boechera constancei (Rollins) Al-Shehbaz, Novon 13: 384. 2003.

Morin, David P., Alexander, Patrick J., Beck, James B., Windham, Michael D. & Bailey, C. Donovan, 2018, Deciphering the sexual diploid members of the Boechera suffrutescens complex (Brassicaceae, Boechereae), PhytoKeys 98, pp. 15-50 : 29-31

Boechera constancei (Rollins) Al-Shehbaz, Novon 13: 384. 2003. Figures 3 , 4 , 6

Arabis constancei ≡ Arabis constancei Rollins, Contr. Gray Herb. 201:5. 1971. Type: U.S.A. California. Plumas County: 7.6 mi SE of Quincy (at Spring Garden Overpass), on road to Blairsden, 11 Jul 1969, L. Constance and T. Chuang 3875 (holotype: GH!; isotype: UC!). GH holotype image - http://kiki.huh.harvard.edu/databases/specimen_search.php?mode=details&id=49339

A. suffrutescens perstylosa = A. suffrutescens S. Watson var. perstylosa Rollins, Rhodora 43: 471. 1941. Type: U.S.A. California. Plumas County: Above the Middle Fork of the Feather River 7.3 mi SE of Quincy, 9 Jun 1938, L. Constance 2309 (holotype: GH!; isotypes: DS, NY, UC!, WS, WTU). GH holotype image - http://kiki.huh.harvard.edu/databases/specimen_search.php?mode=details&id=122692

Description.

Plants long-lived perennials, with woody caudices raised above ground level 1-5 cm, lacking crowded, persistent leaf bases; herbage often with a distinct bluish cast. Fertile stems 1(-3) per caudex branch, each arising from a basal rosette, 1.2-3.0 dm, glabrous or glabrate proximally with few 1-2 rayed trichomes. Leaves at stem bases narrowly oblanceolate, 1.5-4.0 mm wide, entire, ciliate with simple and stalked 2-3(4) rayed trichomes 0.3-0.8 mm, basal leaf surfaces glabrous with ciliate margins to pubescent; cauline leaves 6-12, glabrous, lacking auricles, usually not concealing the stem proximally. Inflorescences unbranched, 5-15 flowered; mature fruiting pedicels 4-12 mm, strongly recurved or reflexed proximally but not distinctly geniculate proximally, glabrous. Flowers divaricate-ascending at anthesis; sepals glabrous; petals 6-8 mm long × 1.5-2 mm wide, creamy white, glabrous; anthers with mostly well formed, narrowly ellipsoid, symmetrically tricolpate pollen; ovules 18-28 per fruit. Fruiting pedicels glabrous, 5-15 mm, recurved but not distinctly geniculate proximally. Fruits 3.6-7.5 cm long× 3.0-3.5 mm wide, pendent or reflexed, usually secund, straight or slightly curved, with undulate margins, glabrous; apical angle of fruit valve 16-25° (measured from base of style to 5 mm proximate); style persistent 1.5-5.5 mm. Seeds uniseriate, 3-4 × 2.5-3 mm; wing continuous, 0.5-1.0 mm wide.

Distribution, habitat and phenology.

Boechera constancei is only known from the western slope of the Sierra Nevada in the vicinity of Lake Delahunty in Sierra County and adjacent southern Plumas County, California. It appears to be confined to a variety of serpentinic substrates in association with Pinus jeffreyi and other "serpentine barren" vegetation types at elevations from 1200-1900 m; flowering from Apr-Jun.

Comments.

Boechera constancei was originally treated as a variety of Arabis suffrutescens s.l., but it is distinguished from members of that group by its non-auriculate cauline leaves, longer (6.0-8.0 vs. 4.5-6.0 mm) petals that are creamy white and longer (1.5-5.0 vs. 0.4-1.2 mm) style. Although restricted to serpentine substrates, it generally shows greater local abundance and higher population densities within its narrow geographic range than B. duriuscula , B. botulifructa and B. suffrutescens s.s.

Specimens examined. California.

Plumas County: Central Sierra Nevada , Plumas National Forest , N side of F.R. 24N20 above East Branch Rock Creek , 1.0 road miles from the junction with 24N28, 1.1 miles NE of Deanes Valley Campground, 4.3 miles WSW of central Quincy, 4 Aug 2009, P.J. Alexander 997 A (DUKE), B, E, F (NMC); Above the Middle Fork of the Feather River , 7.3 mi SE Quincy, 9 Jun 1938, L. Constance 2309 A (GH), A, B (UC); 7.6 mi SE of Quincy (at Spring Garden Overpass ) on road to Blairsden , 11 Jul 1969, L. Constance 3875 (UC), (GH); Sierra Nevada , about 2 miles from Spring Garden on road to Quincy , 20 Sep 1974, J.T. Howell 50896 A - D (CAS); Sierra Nevada. 2 mi. northwest of Spring Garden , 16 Jun 1975, J.T. Howell 51131 A, B (CAS); 2.65 mi W of Round Valley Reservoir dam, 23 Jun 1981, J.T. Howell 54150 (NY); Plumas Nat'l Forest 7.6 mi. SE of Quincy (at Spring Creek Overpass ) on road to Blairsden , 200 yards up steep serpentine slope from train track, 2 Jul 2012, D.P. Morin 36 A - F (NMC); Plumas Nat'l Forest . 16.6 road miles S on La Porte Rd to E turnoff toward Onion Valley Reservoir 30 yards from La Porte Rd as slope steepens, 2 Jul 2012, D.P. Morin 39 A (NMC); 1/ 2 mi. S of La Porte Rd, 1/ 2 mi SE (and above) serpentine cliffs. 1 mi NW of Pilot Peak, 3 Jul 2012, D.P. Morin 44 A, B, C, D (NMC), E, F (DUKE); Plumas Nat'l Forest . 0.5 air mi WSW of Onion Valley Reservior. +/- 16.75 road mi from La Porte turnoff N in East Quincy. Above cliffs ESE of La Porte Rd., 3 Jul 2012, D.P. Morin 45 F, H, L (NMC); Plumas NF; along all roads near Clear Creek NE of Mine Pit, E of Clear Creek, 8 Jun 1983, J.H. Robertson 17217 (UNR); At junctions of roads 26N 18, 26N 92 and 27N92, ca. 0.5 mi east of Long Valley Mine , ca. 4 air miles west of Greenville , 5 Jul 1981, M.S. Taylor 3649 A, B (CAS); S side of Hwy 70 ca. 200 yards S of Spring Garden Overpass ca. 7.5 mi SE of Quincy (T24N, R10E, S25; type locality), 2 Jun 1981, M.S. Taylor 3827 (MO); East side of 25N17, ca. 0.125 mi south of Bean Creek , ca. 0.25 mi north of jct. 25N17 with 25N81 ( Old Mt House Rd. ). Ca. 3.5 air mi NW of Meadow Valley, 22 Jun 1981, M.S. Taylor 3944 (CAS); Both sides of spur road off 26N18, ca. 0.5 mi southeast of Long Valley Mine , ca. 4 air mis west of Greenville , 18 May 1982, M.S. Taylor 4471 A, B (CAS); South side of 27N92, ca. 1.5 air mi southeast of Canyon Dam , 18 May 1982, M.S. Taylor 4474 A, B (CAS); South side of 27N92, ca. 2 air mi southeast of Canyon Dam , 18 May 1982, M.S. Taylor 4478 A, B (CAS); Both sides of road 27N92, near Goldstripe Mine, ca. 2.25 mi SE of Canyon Dam., 18 May 1982, M.S. Taylor 4479 A, B, C (CAS); North side of 204, ca. 1 air mi southeast of Long Valley Mine , ca. 4 air mis west of Greenville , 1 Jun 1982, M.S. Taylor 4582 C (CAS); County Rd 204 ca. 2 mi W from Round Valley (site); Crescent Mills 7.5 USGS quadrangle; NE.25 Section 8, 26 May 2004, D.W. Taylor 19075 A (ORE), A, B (JEPS). Sierra County : About 3/ 4 mile (air) east of Lake Delahunty , about 2 miles (air) northeast of Gibsonville (39°45'01"N by 120°52'39.6"W), 28 Jun 2006, L. Ahart 12874 (JEPS); West slope of the northern Sierra Nevada , 1.8 miles (linear) NE of Gibsonville on the road to Johnsville, 2.3 miles WNW of Mount Etna, 13.2 miles SSE of Quincy, Plumas National Forest , 26 Jun 2009, P.J. Alexander 1046 A (BRY), B, D - F (NMC); Plumas Nat'l Forest . Open serpentine knoll 300 m WSW of Lake Delahunty. 50 m S of sign "Entering and Welcome to Delahunty Lake." 1 mi E from La Porte Rd on McCrea / Johnsonville Rd. Large , healthy population, 3 Jul 2012, D.P. Morin 40 A - D, H (NMC), E, F, G (DUKE), I, J (MO); Plumas Nat'l Forest. From La Porte Rd , 1.8 mi road mi E on McRea/Johnsonville Rd 2ft from N side of road in washed out open serpentine slope, 3 Jul 2012, D.P. Morin 41 A, B, C, D (NMC); Plumas Nat’l Forest. From La Porte Rd, 1.8 road mi E on McRea/Johnsonville Rd 70 ft from S side of Rd., 3 Jul 2012, D.P. Morin 42 A - D (NMC) .

Figures

Figure 3. Geographic distribution of B. suffrutescens (CP-su, SNP-su, and TL-su) and B. rollei (TL-ro) lineages inferred from Analysis 2. A map of Plumas Co., California with distributions of the B. constancei clusters is presented in Fig. 4.

Figure 4. Distribution of diploid B. constancei s. l. and SNP-su clusters in Plumas County, California. CD-co lies to the north of the east branch of the north fork of the Feather River. The type locality cluster (TL-co) exhibited unstable placement in both genetic clustering analyses.

Figure 6. Boechera constancei, Ahart 12,874 (JEPS).