Orchid Species of San Jacinto Mountain
Table of Contents
Corallorhiza maculata, spotted coralroot
Varieties of C. maculata
Epipactis gigantea, stream orchid
Listera convallarioides (Neottia convallarioides), broad-lipped twayblade
Malaxis monophyllos var. brachypoda (Malaxis brachypoda), adder's-mouth
Piperia elongata (Platanthera elongata), dense-flowered rein orchid
Piperia transversa (Platanthera transversa), mountain piperia
Platanthera dilatata var. leucostachys (Platanthera leucostachys), white bog orchid
Spiranthes romanzoffiana, hooded ladies-tresses
| Corallorhiza maculata spotted coralroot | Epipactis gigantea stream orchid | Listera convallarioides (Neottia convallarioides) broad-lipped twayblade | Piperia elongata (Platanthera elongata) dense-flowered rein orchid | Piperia transversa (Platanthera transversa) mountain piperia | Platanthera dilatata var. leucostachys (Platanthera leucostachys) white bog orchid | Spiranthes romanzoffiana hooded ladies-tresses |
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| Corallorhiza maculata spotted coralroot | Epipactis gigantea stream orchid | Listera convallarioides (Neottia convallarioides) broad-lipped twayblade | Piperia elongata (Platanthera elongata) dense-flowered rein orchid | Piperia transversa (Platanthera transversa) mountain piperia | Platanthera dilatata var. leucostachys (Platanthera leucostachys) white bog orchid | Spiranthes romanzoffiana hooded ladies-tresses |
| Fig. 1. Photographs of the seven orchid species at San Jacinto Mountain that we've observed in bloom. One orchid species is missing; Malaxis monophyllos var. brachypoda is presumed extinct here now.
The pictures are not to scale. The target in each pix was cropped, and then scaled to be 167 pixels wide. Top row: frontal view of flowers. Second row: Side view of flowers. Third row: portion of the inflorescence. Fourth row: basal leaves (Corallorhiza maculata has no leaves at all). Fifth row: fruit. Pix of Corallorhiza maculata, Spiranthes romanzoffiana, Platanthera dilatata var. leucostachys, the basal leaves of all species, and the fruit of all except the Epipactis by Tom Chester; all other pix are by Bruce Watts. The side view of the Epipactis flower was flipped horizontally, to have the same orientation as the pix of the other species. Click on the pix to see larger versions. | ||||||
Introduction
Orchids? at San Jacinto Mountain? Don't orchids only grow in the tropics?
Although it is true that most orchid species grow only in the tropics, a small number of orchid species can be found on every continent except Antarctica. We have seven orchid species at San Jacinto Mountain, and we used to have an eighth species which appears to no longer be present. One of those seven orchid species was also thought to no longer be present here, since despite a number of searches for it, it hadn't been seen for 83 years until it was rediscovered in 2020.
Furthermore, our seven orchid species live in an amazing range of habitats, and some have very different lifestyles. One species, Corallorhiza maculata, is a parasitic plant with no leaves, that gets all its nutrients from a fungus that lives in dry areas of pine duff. The other six species all have leaves and photosynthesize. Of those six species, two species, Piperia elongata and P. transversa, grow in dry areas. The remaining four species grow in wet areas. Epipactis gigantea, the stream orchid, typically grows along streams, forming large clumps that are easily visible. Listera convallarioides grows along streams, but is well hidden under other vegetation. Platanthera dilatata leucostachys and Spiranthes romanzoffiana grow in high elevation boggy areas.
Our most common orchid is the spotted coralroot, Corallorhiza maculata, which is so reliably present on many of our high-elevation trails that there are 168 iNaturalist observations of it as of 8 July 2024. On those trails, if we have people with us who have never seen it, they get quite excited when we tell them they are about to see an orchid coming up on the trail. They, of course, are looking for a orchid with big flowers, like the ones women wear at high school proms, and perhaps one from a plant that is growing on a tree.
When we point to a spotted coralroot orchid in full bloom, on a thin stalk growing out of the ground, with flowers smaller than the width of your thumbnail, no one can believe that could be what we are pointing to. But when they see the up close photograph of the flower on their phone or camera, or look closeup with a hand lens, they are amazed that it is a perfect miniature orchid flower, much like those of cymbidiums.
Although spotted coralroot, and the stream orchid, have flowers that are the shape of "typical" orchid flowers, our other orchid species have flowers that might not be recognized as orchid flowers by many people. See Fig. 1 for photos of the other orchids we have seen in bloom at San Jacinto Mountain.
Table 1 lists our orchid species, and gives the number of occurrences for each species, from various sources.
Table 1. The Orchid Species at San Jacinto Mountain
| Scientific Name | Common Name | # locations in our surveys | # of Vouchers | # of iNat obs | Elevation range (feet) |
|---|---|---|---|---|---|
| Corallorhiza maculata | spotted coralroot | 34 | 15 | 168 | |
| Epipactis gigantea | stream orchid | 3 | 37 | 46 | |
| Listera convallarioides (Neottia convallarioides) | broad-lipped twayblade | 1 | 4 | 2 | |
| Malaxis monophyllos var. brachypoda (Malaxis brachypoda) | adder's-mouth | 0 | 1 | 0 | |
| Piperia elongata (Platanthera elongata) | dense-flowered rein orchid | 4 | 2 | 7 | |
| Piperia transversa (Platanthera transversa) | mountain piperia | 3 | 7 | 24 | |
| Platanthera dilatata var. leucostachys (Platanthera leucostachys) | white bog orchid | 16 | 20 | 10 | |
| Spiranthes romanzoffiana | hooded ladies-tresses | 1 | 7 | 2 |
The number of iNat observations for each species was as of 8 July 2024; click on that number to see the iNat obs.
A ninth orchid species, Cephalanthera austiniae, Phantom orchid, was vouchered from San Jacinto Mountain in 1908, and we, and others, have searched hard for it without success. Finally, detective work on that voucher led to the surprising conclusion that the single voucher of it was misdetermined, and the voucher was actually of Corallorhiza maculata.
The rest of this page discusses each species in detail, in alphabetical order by Scientific Name.
Corallorhiza maculata, spotted coralroot
Corallorhiza maculata is our most common orchid by far. On typical high elevation hikes, we see at least one plant, and often five or ten plants, which typically are found in clumps. Our record number of plants in a smallish area is well over 100.
The common name is a direct translation of the scientific name. The root / rhizome resembles a clump of soft corals. The spots are on the lowermost lip of the flower.
C. maculata is the only one of our orchids that have no leaves, and conducts no photosynthesis. Instead, it is parasitic on a below-ground fungus, getting all its nutrients from that fungus.
As a result, this species is only found where its fungus host is found, which is typically in the forest duff. When that duff is burned in a major fire, and especially if the trees that are symbiotic with the fungi are killed, it can take 20 years for the trees, duff, fungus, and orchid to re-establish! (Fire and Ecosystems, p. 218). The 2013 Mountain Fire extirpated this orchid in many places in Tahquitz Valley where it burned. For example, there used to be well over 100 plants along the Willow Creek Trail pre-burn, but post-burn there are only a handful so far.
Most people probably pass right by this orchid without noticing it, even when it is in full bloom, since it is typically a very slender stem only about a foot high, with no leaves, and has a brown color that blends in with the forest duff. Non-botanists might think it is just a stick standing upright on the ground.
In detail, this species looks very different at its different life stages. When it emerges from the ground, it is encased in a sheath; see the three pix of various stages in Don Rideout's iNat obs, and plants a bit farther along in Leeloo Gilet's iNat obs.
The flowers emerge successively from the bottom of the stalk, and develop slowly enough that it is sometimes possible to see buds, flowers, and fruit on the same stalk at the same time.
One of the amazing things about this species is that the fruit is two to three times longer than the flowers, which often remain at the tip of the fruit for a while; see Don Rideout's iNat obs. The fruit begins as a horizontal ovary, but then curves so it is pointed straight down at the ground.
In full flower, this species is quite variable in color. Although typically it is brownish over all, sometimes it is reddish, and color variants can be entirely yellow.
The base of the stalks can persist for a whole year, although that is fairly unusual.
Nearly all flowers get pollinated and form fruit, although the pollinator is not known for sure (Coleman, Wild Orchids of California, pp. 47-48). A single fruit capsule can contain up to four million seeds that are so small that they are close to the resolution limit of our eyes! This large number of seeds is needed because the seed has no food reserves, and will only germinate when the seed comes into contact with the fungus host underground.
C. maculata is the most common Corallorhiza species in California, and is widespread through western and northeastern North America. San Jacinto Mountain is almost the southwestern-most locality for this species, with Palomar Mountain and Volcan Mountain being the most southwestern localities. The type locality of var. maculata is Long Island, New York; that of var. occidentalis is "California" (originally under C. multiflora var. occidentalis).
As long as it has its fungus available, C. maculata pretty much doesn't care where it grows. Although it is purely a higher-elevation species at San Jacinto Mountain, because that is where the forest is here, it grows from sea level to 9000 feet in California, and it can even grow in non-native Eucalyptus groves in California!
Varieties of C. maculata
A large number of varieties have been defined based on color variation, but most sources do not think that color is of taxonomic significance, since almost all regions exhibit such variation in colors.
The latest treatment in the Jepson eFlora accepts two varieties in California based on whether the lip widens to the tip (var. occidentalis) or "± not widening to the tip" (var. maculata). The two varieties are said to be most distinct in eastern North America, and less so in western North America. The Jepson eFlora gives both varieties as occurring in the Peninsular Range, which includes San Jacinto Mountain.
Applying the Jepson eFlora key to photos of the lower lip in iNat observations, Fig. 2 shows examples of what would key to the two varieties from San Jacinto Mountain, along with an example of var. maculata from northern California for comparison.
| "var. maculata, eastern spotted coralroot", using the Jepson eFlora key | "var. occidentalis, western spotted coralroot", , using the Jepson eFlora key | |||
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| Fig. 2. Examples of plants from San Jacinto Mountain that key to the two varieties of C. corallorhiza, using the Jepson eFlora key. Left two columns: var. maculata, eastern spotted coralroot. Right two columns: var. occidentalis, western spotted coralroot.
The examples of var. occidentalis are strongly widened toward the tip. The examples of var. maculata range from flowers with essentially parallel left and right edges, with no widening toward the tip at all, at left in each row, to flowers that have just a small amount of widening toward the tip, which would fit in the "±" adjective, in the second position in each row. All photos are from San Jacinto Mountain except for the leftmost photo in the second row, which is from northern California and was determined as var. maculata by an expert. Click on the pictures for larger versions or to go to the original iNat observation. | ||||
Interestingly, the Jepson eFlora says "Where together, Corallorhiza maculata var. occidentalis typically flowers 2--4 weeks earlier than Corallorhiza maculata var. maculata".
To understand how well the plants at San Jacinto Mountain fit into the varieties, and to check the claimed difference in flowering time, Tom went through the San Jacinto Mountain iNat obs which had flowers, and determined 18 as var. maculata, and 21 as var. occidentalis. There were something like 10 observations with good enough pictures in which it was not clear which variety to call them since they seemed in-between the two varieties.
This immediately called into question as to whether the plants at San Jacinto Mountain could reliably be determined as one of the varieties, if ~1/3 of them went to one variety; ~1/3 of them were intermediate; and ~1/3 of them went to the other variety. A more reasonable interpretation is that our plants are intermediate between the two varieties.
Tom then checked the observation dates of the two varieties to see how well they fit the claimed difference between the varieties. Those dates are as follows:
Table 2. Dates of iNat observations for varieties
| Date | var. maculata | var. occidentalis | Delay in date of var. occidentalis |
|---|---|---|---|
| First observation date in year | May 25 | May 27 | 2 |
| Median observation date in year | June 20 | June 26 | 6 |
| Last observation date in year | July 13 | July 22 | 9 |
None of the differences in the first observation date and median observation date between the two varieties are likely to be statistically significant. Even the nine day difference in the last observation date rests on a single observation. If that observation was not present, the last date for var. occidentalis would be July 12, changing the nine days later to one day earlier.
The observed difference in flowering date is opposite to the claimed difference between the varieties. Instead of var. occidentalis flowering 2 to 4 weeks earlier than var. maculata, it flowers ~one week later (or perhaps at the same time, given the statistical uncertainties). We suspect that difference is primarily caused by the last flowers being smaller, which is typical for most all species.
Furthermore, there is no geographic separation between the varieties.
We conclude that the plants at San Jacinto Mountain appear to be a population that is intermediate to the two varieties, at least in terms of the width of the lower lip, and that it does not make sense to determine any of our plants as one variety or the other. Our plants could be intermediates, or they could be an undefined variety. As a result, Tom removed the variety determinations that he had made for those iNat obs in order to do this analysis.
Tom is continuing to study these varieties, with Keir Morse; see Corallorhiza maculata Varieties. See Fig. 3 of that webpage for a histogram of the lip width ratio for the San Jacinto Mountain plants, compared to the histogram of plants from the type localities of those two varieties.
For completeness, there are two other claimed differences between the varieties:
- The Jepson eFlora also states that the flower bracts of var. maculata are "generally 0.5--1 mm, generally entire", and those of var. occidentalis are "generally 1--2.8 mm, often forked".
- Coleman, in his book, says that "plants with a well-defined mentum" ... "have been referred to as var. occidentalis". A mentum is a "chin-like projection" created when the "bases of the sepals extend backward along the ovary".
There are 15 vouchers of this species at SnJt. 13 are only determined to the species; 2 are determined as var. occidentalis.
Sources and further information:
- Coleman, Wild Orchids of California
- Southwest Colorado Wildflowers for a number of nice pix, and interesting background information on this species.
- Wayne Armstrong's Fungus Flowers for great pix and info about the seeds of this species.
Incomplete below this point
Epipactis gigantea, stream orchid
Epipactis gigantea is very different from our other orchids in a number of ways. It is a large plant, typically 2 to 3 feet tall, and often forms large patches since it spreads by rhizomes. Its flowers are typically several inches wide, larger than the width of your thumb. Its "gigantic" size is why its scientific name is E. gigantea; see Fig. 2.
Fig. 2. The patch of Epipactis gigantea in full bloom near the lower end of the Ernie Maxwell Trail. Pix by Bruce Watts. Click on the pix for a larger version.
E. gigantea has only one major requirement for its habitat: it must have wet roots. Since San Jacinto Mountain is in general a pretty dry place, that limits it to growing along perennial streams, or seep areas that don't dry up.
Most of the locations at San Jacinto Mountain are at the base of the mountain, where the streams have water throughout much of the year, such as the lower ends of Andreas and Tahquitz Canyons on the east side, and the lower end of Snow Creek on the north side. It is found in places along the usually good-flowing streams in Dark Canyon, and is found at Halfway Spring on the Control Road. Our most unusual location is in an area near the lower end of the Ernie Maxwell Trail that apparently has high groundwater throughout the year, perhaps from a combination of heavy snow accumulation there, groundwater flow below ground, and a very shady location.
E. gigantea is the most common orchid species in California.
Listera convallarioides (Neottia convallarioides), broad-lipped twayblade
Malaxis monophyllos var. brachypoda (Malaxis brachypoda), adder's-mouth
Piperia elongata (Platanthera elongata), dense-flowered rein orchid
Piperia transversa (Platanthera transversa), mountain piperia
Platanthera dilatata var. leucostachys (Platanthera leucostachys), white bog orchid
Spiranthes romanzoffiana, hooded ladies-tresses
Spiranthes 7 vouchers from 5 collection events, 8/2/1916; 9/5/1922; 9/6/1922; 9/6/1929; 8/18/1937. three localities: Meadow north of Tahquitz Valley (Occasinal in wet meadow.); Tahquitz Valley (Marsh in meadow. (Near the old cabin).); Round Valley. 3 collection events determined as S. romanzoffiana (Meadow north of Tahquitz Valley; Tahquitz Valley); 2 determined as S. porrifolia (Round Valley, Tahquitz Valley).
Malaxis 1 voucher, from "Meadow north of Tahquitz Valley", "Rare in wet meadow, growing on small elevation.". Munz 6366, 5 September 1922, determined by R.A. Coleman in 1992.
How to Distinguish the Species
Abundance and Geographic Distribution of Each Species
The following maps are from our data and from iNat locations. The maps are currently in graph form. These maps will be replaced by maps showing geographic features in the future. There was a problem retrieving vouchers from CCH2, so voucher locations are not yet given in these maps.
Maps are not given for species with uncertain locations, Malaxis and Spiranthes.
The Piperia maps should be taken with caution, since many of the iNat observations are only of leaves, not flowers.
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| Fig. 1. Maps of the San Jacinto Mountain orchid species that have good locations. The first three maps have axes with the same range. The map for Epipactis extends much farther to the east since it is found at the base of San Jacinto Mountain near Palm Springs, whereas the others are all higher-elevation species. |