Plant Species of the San Jacinto Mountains
Garrya fremontii, Fremont Silk Tassel
Fig. 1. Silk tassel bushes are very distinctive plants, with their flowers in "silk tassels" (top left) and with opposite leaves (top right). Garrya fremontii is distinguished from other Garryas by its lack of hairs on mature leaves (top right). Each plant is either male (bottom middle, showing the typically three flowers per bract, each with four stamens) or female (bottom left, showing the one to three flowers per bract, each with two styles). The fruit (bottom right) is a berry, with two seeds.
Photographs by Tom Chester except the bottom middle photo by Matt Berger. Click on the photographs for larger versions.
Garrya fremontii is one of our rarest species in the San Jacinto Mountains. We've seen only about 150 plants TOTAL in our extensive surveys here, with almost half of those plants present on the Devils Slide Trail and on the PCT just north of its upper end.
G. fremontii is rare in all of southern California. It primarily grows in the northern half of California and southern part of Oregon; see the CCH2 map of voucher locations. In southern California, it skips the San Gabriel and San Bernardino Mountains, and is only present in the San Jacinto Mountains, Palomar Mountain (one location near Morgan Peak), and the Cuyamaca / Laguna Mountains (two locations - Monument Peak, and on gabbro north of Cuyamaca Peak), and is not abundant in any of those locations. For example, we found just two plants in the Cuyamaca Peak area, and one of the vouchers from there says "rare, only 1 plant seen".
Vouchers incorrectly appear to indicate that G. fremontii is a bit more widespread in southern California than it actually is, since sparsely-hairy specimens of G. flavescens are sometimes misdetermined as G. fremontii. Young leaves of G. fremontii have sparse hairs similar to those of mature leaves of G. flavescens, but those hairs are quickly lost, leaving the mature leaves of G. fremontii glabrous. Also, most specimens of G. flavescens have straight hairs, whereas the hairs of G. fremontii are wavy.
G. fremontii in southern California is strictly a high-elevation species. At San Jacinto Mountain, it is present at 6905 to 8935 feet elevation.
The pendulous flowers of Garrya species are primarily wind-pollinated.
G. fremontii appears to be on the way out of southern California, due to the surprising number of locations where only a single plant is found. Those locations with a single plant will eventually have no plants, since a single plant cannot reproduce unless it can be wind-pollinated by a nearby plant.
Distribution in the San Jacinto Mountains
The plots in this section show the two Garrya species present in the San Jacinto Mountains, G. fremontii and G. flavescens.
The plots are made from GPS records from our surveys, along with iNaturalist observations downloaded as of 28 June 2021. The iNat observations were reviewed for accuracy of determination and location. Only observations with locations accurate to 100 m were accepted. Voucher locations were not used since there were only three collection events in the San Jacinto Mountains, and only one of them had an accurate location that was already present in our survey records.
There were 24 GPS points of G. fremontii from our surveys. No additional locations were contributed by iNat observations.
There were 35 GPS points of G. flavescens from our surveys. iNat contributed 88 locations of G. flavescens from both the San Jacinto and Santa Rosa Mountains. One iNat observation of G. flavescens was a misdetermined G. fremontii at the location of one of our survey locations of it. Due to the large number of iNat observations with good locations, we did not use or review the 19 voucher locations of G. flavescens in our area, many of which had very imprecise locations such as "San Jacinto Mountains" and "along Idyllwild to Tahquitz Peak Trail".
A map of all the known locations of G. fremontii in the San Jacinto Mountains is shown in Fig. 2, labeled by the number of plants at each location found in our surveys.
Fig. 2. Map of all the known locations of G. fremontii in the San Jacinto Mountains, with each location labeled by the number of plants found in our surveys. The largest concentration of plants is on the Devils Slide Trail (an actual count of 49 plants) and on the PCT just above its upper end (an estimate of at least 20 plants), with the total rounded to 70 plants. See also map without the labels.
A closeup of the main population in the area of the Devils Slide Trail is shown in Fig. 3.
Fig. 3. Map of all the known locations of G. fremontii on the Devils Slide Trail and nearby. Most of the 49 plants on the Devils Slide Trail are found in the rock cliffs area near the top of the trail. A minimum of 20 plants were found on the PCT north of Saddle Junction, and only a single plant was found on the PCT north and west of there.
Fig. 4 shows the geographic distribution of both G. fremontii and G. flavescens in the San Jacinto Mountain area. G. fremontii is found only at the contiguous higher elevations of San Jacinto Mountain, with G. flavescens found only in surrounding areas.
Fig. 4. Map of all the known locations of G. fremontii and G. flavescens in the San Jacinto Mountains. The northernmost point of G. flavescens is on the Skyline Trail, on the steep eastern slope above Palm Springs.
A plot of elevation vs. longitude is shown in Fig. 5. There is good separation in elevation between the two species in San Jacinto Mountain proper (excluding the Santa Rosa Mountains), with only the specimen of G. flavescens from the Skyline Trail in the range of elevations for G. fremontii. Three specimens of G. flavescens at high elevations of the Santa Rosa Mountains also overlap with the lowest elevations known for G. fremontii, with the highest elevation specimen at 7290 feet.
Fig. 5. Elevation vs. Longitude of all the known locations of G. fremontii and G. flavescens in the San Jacinto Mountains. At San Jacinto Mountain proper (longitudes west of -116.59°), G. fremontii is found at higher elevations than G. flavescens, with the exception of the plant of G. flavescens from the Skyline Trail, on the steep eastern slope above Palm Springs. That plant is found significantly to the east of the G. fremontii population; see Fig. 2.
The only location where the two species are physically close is at the top of the Cedar Spring Trail. G. flavescens is found at the intersection of that Trail with the PCT. G. fremontii is found 0.56 miles northwest of that location along the PCT, 200 feet higher in elevation.
We thank Deborah Burroughs, Cathy Peterson, and Don Rideout for their help in surveying for and counting the G. fremontii population on the Devils Slide Trail. We thank all the people at iNat who have posted observations of Garrya species there.
Copyright © 2021 by Tom Chester and Dave Stith.
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Updated 30 June 2021.