Flora of Idyllwild Park, San Jacinto Mountains
Introduction
Fieldwork Dates
Floral Regions
Species Checklist
Notes on Some Species
Fig. 2. The flora of Idyllwild Park contains flowers large and small. Note the fingers for scale in the upper pictures, and the pine needles, branches and one incense-cedar twig for scale in the linked version of the lower picture. Click on the pictures for larger versions. See Michael Charters' Field Trips Photo Gallery: Idyllwild County Park, San Jacinto Mountains, June 2010 for other pictures of flowers from Idyllwild Park.
- Upper left: the almost-unnoticeable teeny-tiny 3 mm (0.1 inch) flower of Parikh's threadstem, Nemacladus parikhiae, a species only described in 2020.
- Upper right: the large showy flower of lemon lily, Lilium parryi, ~12 cm (5 inches) across, the probable namesake of Lilly Creek. (Picture from Tahquitz Valley since we do not yet have a picture of a lemon lily flower from Idyllwild Park.)
- Lower: a field of flowers of volcanic gilia, Gilia ochroleuca ssp. exilis, and Palomar monkeyflower, Mimulus diffusus (called M. palmeri in the Jepson Manual), covering an area.
Introduction Idyllwild Park, a Riverside County Park, is located on the west side of Idyllwild. The Park contains a Nature Center on the north side, and a campground on the south side. Day use fees of $3 per adult, $2 per child and $1 per dog are charged.
The Park is roughly one mile long in the north-south direction at its maximum extent, and one half mile long in the east-west direction at its maximum extent. Its shape is roughly rectangular, with a rectangular piece missing on its northwest corner and a triangular piece missing on its southeast corner, with a total area of 202 acres.
Lilly Creek is the main feature of the western part of the Park, essentially forming the western boundary in the north Park and cutting a steep and deep gorge through the south Park as erosion has proceeded upstream from Strawberry Creek. There is over 560 feet of relief from the bottom of Lilly Creek to the top of the knolls above its banks (5200 feet elevation to over 5760 feet).
The USGS Topo Map uses the name Lilly Creek, although it is given as Lily Creek in other sources. The origin of the name is unknown. But since lemon lilies grow in the creek, it is probable that is the origin of the name. Historic references often spell lily as lillies, so the difference in the spelling is not significant.
Idyllwild Creek is the main topographic feature of the eastern and southeastern sides of the park, although most of the northern part of the creek is on private property to the east. The name Idyllwild Creek appears on a local Idyllwild map, but not on the USGS Topographic Map. Idyllwild Creek has a steep western bank extending to Idyllwild Park, and a gentle eastern bank that is essentially a relatively minor feature in Strawberry Creek Valley. Because of the latter, Idyllwild Creek is flatter in elevation profile along its course than Lilly Creek. Idyllwild Creek forms the southeastern boundary of the park and joins Lilly Creek near the southern end of the Park.
The topography of the Park is shown in the Google Earth image in Fig. 3:
The elevation profile of Lilly Creek in Idyllwild Park confirms what is seen in Fig. 3. The erosional nick point, shown by the yellow circle in the middle of the profile, occurs just southwest of the Nature Center, at the location shown in Fig. 1. Above that, the creek elevation profile has a constant slope of about 450 feet per mile. Below that the creek has an elevation profile of about 1200 feet per mile until it levels out in the flattish Strawberry Creek area.
Idyllwild Park has a rich vascular-plant flora due to its many different habitats resulting from its topography, and the fairly well-watered Lilly Creek, at least before it was dammed at Foster Lake with upstream diversions for the Idyllwild Water District.
Fieldwork Dates Our main plant surveys occurred on all-day trips on 15, 21 and 25 June 2010, and 20 November 2012, by the following people:
Table 1. Major floral surveys of Idyllwild Park
Date Surveyed Area of Park Participants 15 June 2010 Northwest, mostly on trail Tom Chester, Dave Stith and Kay Madore 21 June 2010 Northwest, mostly in Lilly Creek Tom Chester, Dave Stith and Michael Charters 25 June 2010 Southwest, mostly on trail, and Northeast Tom Chester, Dave Stith and Michael Charters 20 November 2012 Southeast and Northeast Tom Chester and Dave Stith On each survey, every species encountered was recorded, with its first location recorded by GPS. Abundances were estimated for each species at the end of each survey, by estimating the minimum number of plants we saw along our entire survey up to a maximum of 99 plants.
In addition:
- Dave Stith did shorter surveys on 1 and 5 September 2010; 19 and 20 April 2011; 13 June 2011; 8 July 2011; 31 December 2011; 2 May 2013; and 16 June 2013, usually with one or two species as targets.
- Bruce Watts did bloom surveys on 22 and 29 April 2017, recording all species in bloom, as well as finding Collomia on 17 June 2013 and teasel in 2012, and counting the Calochortus on 26 June 2016.
- Tom Chester and Nancy Accola surveyed most of the Park on 2 May 2017, with Bruce Watts joining us for the first half of the survey, looking for additions to the flora, checking on some species observed in the past, and updating abundances for some species.
- Tom Chester, Keir Morse, Don Rideout, and Bruce Watts botanized the park on 22 May 2017 to check on a number of species that needed further work.
- Tom Chester botanized the park on 21 September and on 7 October 2020 to check on some species and to look for additions to the flora that might be visible at this time of year.
Floral Regions Our surveys showed dramatic differences in the flora between different areas of the park, so we decided to present the flora separately for three different areas of the park. Our division is shown in Fig. 4, which also shows the hiking trails of the Park. As is almost always the case, boundaries between areas are sometimes somewhat arbitrary.
Fig. 4. Map showing Idyllwild Park, its hiking trails, and division into three floral areas (larger version). Base map from Riverside County Parks
The Southwest area has the clearest delineation, being the only part of Idyllwild Park significantly west of Lilly Creek, with a large area of chaparral plants not present in the rest of the Park. Its boundary with the southeast section is taken to be between the Hillside Trail and the Campground Road.
The Southeast area has extensive flattish moist areas not present in the rest of the Park; the only meadow in the Park; significant human disturbance from the 88 site campground; and borders an extensively-developed residential area. Its northern boundary is taken to be approximately along the top of the steep area to the north. This roughly corresponds to the northern boundary of the southwest section. Trails from the Nature Center that lead to the campground allow a fairly clear delineation on the north, except along the Perimeter Trail. Fortunately, the flora doesn't vary much in that section of the Perimeter Trail, so it makes little difference exactly where the boundary is placed.
The southeast portion has south-facing slopes similar to those of the southwest portion.
The North area is distinctive due to its terrain being above the erosional nick point, and hence not as steep as in the other two sections. Probably as a result of its gentler topography, it is covered by pine forest with no significant chaparral component. It contains the upper portion of Lilly Creek, which has a flatter elevation profile in the north.
The routes we have surveyed as of 24 November 2012, along with the GPS points where the first occurrence of species were recorded, are shown in this map (The GPS points shown on the north side of State Route 243 were not used for the Park Flora.) Although our surveys were not done with these divisions into flora areas in mind, our surveys were perhaps not-coincidentally usually confined to one area.
A few surveys crossed boundaries of the floral areas. For those, it was straightforward to use the GPS locations to assign the first location of species to floral areas. However, plant abundance estimates from those surveys could not be ex post facto separated into the floral areas.
Another effect from surveys that crossed boundaries is a possible loss of completeness in the checklist for the second floral area traversed. This occurs when species are present in both floral areas, since those species would be recorded only from their first location, which would be in the first floral area traversed. Fortunately, we have enough surveys beginning in each area that this loss of completeness is probably not high.
Now that we have the floral areas defined, future surveys can produce better abundance estimates and species lists for each area.
Species Checklist The following is the latest plant checklist for the park from all surveys to 21 September 2020. One species, Orobanche fasciculata (= Aphyllon fasciculatum), came from an iNaturalist observation, and might in fact be an undescribed species, since its flowers are white, not yellow.
We would have included vouchers from Idyllwild Park, but there are no vouchers online that we can be certain have come from the Park itself. There are no online vouchers as of 29 November 2012 whose locality is Idyllwild Park. There are many vouchers with a locality of Idyllwild; we have collected those separately in a Voucher Flora of the Idyllwild Area. However, some of those vouchers are not in fact even from Idyllwild itself, since vouchers often just list the nearest city within 20 miles or even more.
Basic information about the checklist presentation and links:
- Notes on the Scientific Names Used At This Site and
- Information about the links from the Scientific Name and Common Name.
Three species have qualifiers given in front of the scientific name, indicating that the species determination is not 100%. Notes on some of those species are given in the next section.
An asterisk before the Common Name indicates a non-native taxon.
The three columns under the header #Plants give a minimum estimate of the number of plants we saw along our entire survey in each area (up to a maximum of 99 plants). The southwest area (SW) is presented first, since its flora is significantly different from the other two areas, being dominated by chaparral. The other two areas, the north half of the park (N) and the southeast part of the park (SE), have significant riparian areas and are dominated by the pine forest.
For photographs of many of the species from here, see:
- Field Trips Photo Gallery: Idyllwild County Park, San Jacinto Mountains, June 2010 by Michael Charters for photographs of many of these species from 6/21/10 and 6/25/10.
- iNaturalist observations for Idyllwild Park. As of 20 September 2020, there are 304 observations from this area. Don Rideout has contributed the most observations, 45 observations of 44 species, with 77 other observers contributing observations. Be aware that we have not reviewed the determination of most of these observations. Many are not identified to species, and some are incorrectly identified.
This checklist, the version as of 9 March 2021, is also in PlantID.net (except for one species, Nemacladus parikhiae). The list there allows different displays of this checklist, including an illustrated one, and allows searches on some plant characteristics; see Information about PlantID.net.
The PlantID.net platform provides the following information about the lifeforms of the species on this checklist. It contains:
- 22 trees, of which 15 are broadleaf trees and 7 are conifers.
- 24 shrubs. Some plants can sometimes be trees, and sometimes shrubs, so there is overlap in the numbers of shrubs and trees.
- 5 vines.
- 165 herbaceous plants.
- 6 ferns.
- 39 grasses, sedges, and rushes.
Update on 4 July 2021: Deborah Burroughs found three to five Garrya flavescens plants on the south side of the small peak that is immediately south/southwest of the Visitor Center. This will be added to the checklist the next time it is updated.
Version for printing, without other text on this page: html (8 pages) or pdf Clickbook booklet (2 double-sided pages). (See printing instructions for an explanation of these options)
Notes on Some Species Hesperocyparis stephensonii. There are about 10 mature trees that have been planted along the southernmost boundary of the park next to a residential area. Since these are planted trees, they could be Hesperocyparis arizonica, or some hybrid between those two species.
Mimulus diffusus. The Jepson Manual First and Second Editions combined this species with the similar M. palmeri species found in the Transverse Ranges and north. M. diffusus is endemic to the Peninsular Ranges and was considered separate from M. palmeri in Munz 1974. Fraga (2012) demonstrated that there were actually five separate species lumped under the name M. palmeri, and restored M. diffusus as a separate species. Fraga updated the Jepson eFlora treatment in 2018 and restored this species, now under the name of Erythranthe diffusa.
Helianthus californicus. This species is found in only one spot, just below the trail southwest of the Visitor Center where it crosses Lilly Creek. It is short rhizomed, and therefore produces a lot of stems, each spaced a few inches apart. Tom's count was 47 live stems in 2020, not all of which produced flowers.
We thank Deborah Burroughs for the minimum estimate of the number of plants of Umbellularia californica, California bay.
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Copyright © 2010-2020 by Tom Chester, Dave Stith, Bruce Watts, Michael Charters, Keir Morse, Don Rideout, Kay Madore, and Nancy Accola.
Commercial rights reserved. Permission is granted to reproduce any or all of this page for individual or non-profit institutional internal use as long as credit is given to us at this source:
http://tchester.org/sj/flora/idyllwild_park.html
Comments and feedback: Tom Chester
Last update: 11 October 2020; link to PlantID.net added 9 March 2021; links to Riverside County Parks removed on 17 May 2021 since the county broke all the links; update to mention Garrya flavescens on 4 July 2021