Plant Species of San Jacinto Mountain:
Delphinium parryi, blue larkspur, and D. patens, spreading larkspur
D. parryi ssp. parryi D. patens ssp. montanum Fig. 1. Left: Part of a flowering stem for D. parryi ssp. parryi at peak bloom, from Kenworthy on 1 June 2017. Right: The entire flowering stem for D. patens ssp. montanum just beginning peak bloom, from the Old Control Road east of Chimney Flats on 1 June 2017. The photographs are shown here at the same scale. The appearance and size of the individual flowers are approximately the same for the two species, but the number of flowers open at one time is much larger for D. parryi. Note also the difference in the thickness of the stem.
Click on the pictures for larger versions.
This page shows how to discriminate our two Delphinium species with blue flowers found west of the Desert Divide, and gives the geographic distribution maps for them. Our two species are Delphinium parryi ssp. parryi and D. patens ssp. montanum. We have a third blue-flowered species, D. parishii, east of the Desert Divide, from Ribbonwood down to the desert, which is quite similar to D. parryi except for the lower stem hairs, but isn't otherwise discussed here.
How To Identify Delphinium parryi and D. patens at San Jacinto Mountain
These two species are fairly easy to discriminate at San Jacinto Mountain even though their individual flowers are almost identical in size and appearance. The main differences are as follows:
- The number of open flowers on the main stalk at peak bloom. Fig. 1 shows a dramatic difference between the two species in the number of flowers that are open at a single time. On 1 June 2017, Tom measured a range of three to five flowers open at the same time for D. patens, compared to 11-14 flowers open at the same time for D. parryi. Those numbers are only a sample of the range for the number of open flowers at the same time for each species, since Tom did not do an exhaustive field survey to get that range. The fieldwork that day concentrated on measuring a large number of characteristics for a handful of individual plants.
The number of flowers open simultaneously on the main flowering stem at peak flower is one of the characteristics used in the Jepson Manual key to discriminate groups of species that contain these two species:7. ... inflorescence in mid-flower with generally < 6 flowers on main axis ==> D. patens
7'. ... inflorescence in mid-flower with generally > 6 flowers on main axis ==> D. parryi
Note that this characteristic can only be used on the main flowering stem, and not on the side branches which may have a number of flowers as well. The Jepson Manual key probably underestimates the actual difference in the number of flowers because D. parryi is a widespread species with a number of subspecies. On the other hand, depauperate plants of D. parryi might not even have six flowers total.
- The shape of the leaves. This is probably the easiest characteristic to check at a glance, since the leaves of these two species are dramatically different, as shown in Fig. 2. D. parryi has cauline leaves with 5 to 14 linear lobes, whereas D. patens has cauline leaves with just 3 to 5 lobes wider than linear. In addition, D. parryi usually has a number of cauline leaves, whereas D. patens has just a few.
D. parryi ssp. parryi D. patens ssp. montanum Fig. 2. Left: The cauline leaves for D. parryi ssp. parryi at peak bloom, from Kenworthy on 1 June 2017. Right: The cauline leaves for D. patens ssp. montanum just beginning peak bloom, from the Old Control Road east of Chimney Flats on 1 June 2017.
Click on the pictures for larger versions.
- The hairs on the stem and petioles. This is not a completely-reliable separation, but works in most cases. D. parryi always has dense short curved hairs on its stem. D. patens generally has few hairs on its stem, but those hairs can also be short and curved at times, too. See Fig. 3.
D. parryi ssp. parryi D. patens ssp. montanum Fig. 3. Left: D. parryi ssp. parryi has dense short curved hairs on its stem and petioles. Picture from Kenworthy on 1 June 2017. Right: D. patens ssp. montanum is nearly glabrous, with few hairs at all on its stem and petioles. Picture from the Old Control Road east of Chimney Flats on 1 June 2017.
Click on the pictures for larger versions.
- Whether the basal leaves are withered in flower or not. This is also not a completely-reliable separation, but generally the basal leaves of D. parryi ssp. parryi are withered when the plant is in peak bloom, whereas the basal leaves of D. patens are not.
- Shape of the fruit. The shape of the fruit is different, although the difference is somewhat subtle at times. The fruit of D. patens is always curved, with the three segments diverging from near their base. The fruit of D. parryi is usually straight, but can sometimes be curved almost as much as the fruit of D. patens at the top. However, the three segments only diverge above the middle of the fruit. See Fig. 4.
The fruits shown in Fig. 4 also have different trichomes (hairs), with the fruit of D. parryi having the same short curved hairs as the rest of the plant, whereas the fruit of D. patens has translucent multicellular hairs with enlarged tip that may or may not be glandular. This difference is not noted in the floras, so we don't know whether this is generally a good separation characteristic, or just works at San Jacinto Mountain.
D. parryi ssp. parryi D. patens ssp. montanum Fig. 4. Top: Photographs of the fruit of D. parryi and D. patens, labeled by species and location. Fruit from three different populations of D. parryi shows the variation from erect fruit with straight sides to erect fruit curved above the middle of the fruit. The fruit of D. patens is curved outward from near the base of the fruit.
Bottom left: One fruit of D. parryi showing short curved hairs. Bottom right: One fruit of D. patens showing what appears to be translucent multicellular hairs with enlarged tip that may or may not be glandular.
As always, it is best to use several characteristics to identify a specimen and not to rely on any single characteristic.
Habitat and Distribution at San Jacinto Mountain
The habitat of these two species is quite different at San Jacinto Mountain. As you might expect from the name, D. patens ssp. montanum is found in the Pine Forest. It appears to grow in a variety of habitats in the Pine Forest, including at the edges of the Forest. It occurs only in shadier areas, such as north-facing slopes and in more open areas that are shaded most of the day by tree canopies. It is often accompanied by Chinese Houses, Collinsia concolor, and is unfortunately often fighting with Bromus tectorum for those locations.
In contrast, D. parryi ssp. parryi is mostly a chaparral species, often growing through other plants. Many of the plants we saw were unapproachable because the plants were growing amidst prickly pear cactus, or inside chamise or Cercocarpus betuloides plants.
Fig. 5 shows the geographic distribution of all vouchers with fairly good locations, as well as the locations we've recorded D. patens.
Fig. 5. Geographic distribution of all vouchers of D. patens and D. parryi with fairly good locations, as well as the locations we've recorded D. patens. See Fig. 6 for a map for each species separately showing the terrain and geographic features.
The following maps show the locations on a map background of these points that are not to the same scale in order to show the locations of D. patens more clearly. Click on the maps for larger versions.
Fig. 6. Left: Locations of D. parryi. Right: Locations of D. patens. The maps are not to the same scale, in order to better show the locations of D. patens. See Fig. 5 for a map showing both species. Click on the pictures for larger versions.
The two species are almost completely-separated geographically, with the exception of one location for D. patens in the Idyllwild area near three vouchers of D. parryi; see elevation plot below for more information.
D. patens is the only one of these two species found at elevations of 4600 to 5500 feet on the west side of SnJt (west of the longitude of Idyllwild). This is quite different from the ecology given in the Jepson Manual treatment, which places it in drier, eastern sides of mountain ranges.
The following figure shows a plot of the elevation vs. longitude for these locations.
Fig. 7. Elevation vs. longitude for D. patens and D. parryi.
The voucher location of D. patens at 4000 feet elevation seems out of place. We intend to check that location soon to see if the voucher is misdetermined.
The voucher location of D. parryi at 5300 feet elevation also looks to be out of place. That voucher is from vicinity of Chalk Hill, which is a disjunct area of chaparral at high elevation surrounded by the pine forest. It would be reasonable that D. parryi, a chaparral species, would be found in that location.
We thank Nancy Accola and Bruce Watts for help with the fieldwork on 1 June 2017.
Copyright © 2017 by Tom Chester and Dave Stith.
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:
Comments and feedback: Tom Chester
Updated 10 June 2017.