Introduction Flora of Blue Ridge Trail / Big Pines Area, San Gabriel Mountains
Botanical Highlights
The FloraIntroduction
This flora came from:
- field work on 16 September 2014 by Tom Chester, Keir Morse and Adrienne Ballway. This survey was done late in the year, in a poor rainfall year, so some dead annuals could not be positively identified, and many species were probably missing.
The survey was of the 2.0 mile Blue Ridge Trail, from the trailhead sign near Big Pines at 6860 feet elevation, to the junction of the Blue Ridge Road in the Blue Ridge Campground at 7900 feet. The survey included species seen in the moist area directly between the Big Pines Trailhead and the Angeles Crest Highway.
- a Consortium of California Herbaria search on 15 September 2014, for vouchers with coordinates from 34.36 to 34.38° latitude and -117.70 to -117.68° longitude, and for vouchers with Big Pines in their localities. For the latter set, the locality was examined and only those that were clearly east of the Big Pines / Angeles Crest Highway junction were retained.
All voucher localities were examined for ones in Big Pines Meadow; in Swartout Valley (east of the aforementioned junction); or in the Blue Ridge. Species vouchered from those localities are identified in the checklist.
Voucher georeferencing is quite problematic for this area, since many of them simply have Big Pines as their locality, and the vouchers could have been taken from miles away. As a result, at least some of the vouchered species are probably not in the Blue Ridge Trail area. For example, the vouchers of Pinus ponderosa were probably taken in the area west of Big Pines near the organizational camps, since we only found P. jeffreyi in our survey. None of the localities for P. ponderosa vouchers were identified as being in the localities mentioned in the previous paragraph. Hence we rejected that species from the list.
RT Hawke pointed out that the voucher of Astragalus purshii var. tinctus was likely to be a misdetermined A. leucolobus, since there are only two very old (1899 and 1931) georeferenced voucheres in this area of it, compared to 19 vouchers of A. leucolobus. Hence Astragalus purshii var. tinctus was rejected from the checklist.
Astragalus douglasii var. parishii was rejected from the list since most vouchers here are of var. douglasii.
Oenothera deltoides was rejected from the list since it almost surely was not actually taken from this area, or, if it was, it was a waif.
Phacelia egena was rejected from the list as an almost certain misdetermination of the P. imbricata plants here, which are intermediates between its two subspecies. See Flora of Table Mountain for more information from Heckard's monograph on this group of Phacelia species.
Eriogonum wrightii var. subscaposum was rejected from the list as a misdetermination of the Eriogonum umbellatum var. munzii plants abundant along the trail. Variety subscaposum is a significantly taller shrub which appears to be found only in the Mojave Desert environs just north of the Wrightwood Area, in association with Joshua Trees.
Species note. The plants here that correspond to Ericameria nauseosa var. mohavensis and var. oreophila along the Angeles Crest Highway and environs appear to be a single population that is intermediate between those two varieties, and thus some have been vouchered as one variety and some as the other. We've arbitrarily assigned the plants here to var. oreophila, but note that a Principal Components Analysis that we've done shows that they are distinct from the oreophila plants in San Antonio Canyon. Variety bernardina is quite distinct from this intermediate population, and is also present here.
Botanical Highlights
The north side of the Blue Ridge is the only place in the San Gabriel Mountains which contains ranger's buttons, Sphenosciadium capitellatum. These are not found directly on the Blue Ridge Trail; they are just above the trail at the drainage at mile 0.70, just above (34.37199, -117.68540) at 7020 feet elevation. In addition to these plants in the area of this trail, they also occur in Buford Canyon (Swinney 5658; Walt Fidler reported a gigantic patch of them there) and also in Government Canyon (observed by Walt Fidler). Government Canyon is the next canyon east of the area of the Blue Ridge Trail, with Buford Canyon the next canyon east of Government Canyon.
There are vouchers from Big Pines Park, which may refer to one of these localities, or may come from another nearby area.
The north side of the Blue Ridge also has perhaps the densest easily-accessible stands of Salix scouleriana in the San Gabriel Mountains. The only other locations for this species, from vouchers, in the San Gabriel Mountains is the Pine - Dawson - Baldy Ridge; north and east of Baldy Notch; Icehouse Canyon; and San Sevaine Flats. Not all of those locations may actually contain S. scouleriana, since without flowers, specimens of S. lasiolepis are easy to confuse with S. scouleriana.
The Flora
The column #V gives the number of georeferenced vouchers found in the search detailed above.
The column Mdw indicates species vouchered from the Big Pines Meadow.
The column BR indicates species vouchered from Swartout Valley or in the Blue Ridge.
The column #Pls gives a rough estimate of the minimum number of plants seen in the 15 September survey, with a maximum value of 99 plants. The main intent of this column is to indicate the species for which we found very few plants. The species identification is uncertain if there is a ~ or ? along with the number. A V in this column indicates a species vouchered from the Blue Ridge Trail that we didn't see in our late-season survey.
Species with no entry other than in the #V column may have been collected west of the Big Pines / Angeles Crest Highway junction.
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Voucher data provided by the participants of the Consortium of California Herbaria (ucjeps.berkeley.edu/consortium/) on 4 July 2014.
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