Plant Species of San Jacinto Mountain: Salix species, willows
Fig. 1. The two most common willow species above 6500 feet elevation at San Jacinto Mountain: Salix scouleriana at bottom left; S. lutea at upper right. The difference in shape of the leaves is the most reliable separation, since the color difference is rarely as obvious as it was for these two plants. Willow Creek, 8 August 2009. Click on picture for larger version.
Table of Contents
Introduction
The San Jacinto Mountain willow species found above 4000 feet elevation
Comparison of the species found above 7000 feet elevation
Pictures of S. lemmonii
Pictures of S. lutea
Pictures of S. scouleriana
References
Introduction
In determining willows one is only too often entirely misled at first, and even by a slow and careful examination it is not always possible to determine the proper identity of the plant.Quote from C. K. Schneider, the foremost European Salicologist of his day, in his 1919 monograph on Salix, J. Arnold Arboretum 1: 85, from Argus (2005).
Willows are certainly a difficult genus if you have to work with all the species in the genus, or even if you just have to work with some of the problematic species to separate. Fortunately, at elevations below 6000 feet in coastal southern California, there are only five species, which are essentially a piece of cake to separate.
The higher elevations of San Jacinto Mountain contain three species not found below 6000 feet, and those species are in some cases fairly similar at times to at least one other species. This makes it a bit more troublesome to separate the species in some cases, and the quote above is thus more pertinent. Most plants are fairly easily determined from the leaves alone, but some plants require further work to separate, such as examination of flowers. Even then, some plants will require further careful study in order to determine them.
George Argus (2008) offered excellent advice on how to identify willows:
The accurate identification of Salix is not always easy. Nor is it easy to write keys that will identify more than a small percent of unknowns. With practice one can come to know the species by "the way they look." This recognition of general patterns brings into play many more characteristics than can be described in words. These include the general branching pattern, overall color, the way the leaves are borne on the shoot, the appearance of catkins and leaves when they are very young, etc. Field identification comes to rely on these characters despite their variability and the possibility of being misled by superficial look-alikes or developmental variation. An important rule is to exercise caution and to carefully check the unknown against its description or by comparison with herbarium specimens.
We have been a bit mortified that during the writing of this page we have come across specimens in our photographs that we had misdetermined in the field from a quick glance. Hence we firmly echo the advice to exercise caution, since it is easy to be fooled into the wrong determination by just a casual glance.
This page is not complete yet, but it has enough information on it that we are putting it online despite the incompleteness.
The San Jacinto Mountain willow species found above 4000 feet elevation
There are six willow species at the higher elevations of San Jacinto Mountain, above 4000 feet, with only three of them found above 7000 feet.
Table 1 gives the numbers of areas we have surveyed at San Jacinto Mountain that contain each of the six species, along with the elevation range for each species, both from our surveys and from vouchers we've deemed "probably reliable". Our surveyed areas are mostly above 4000 feet elevation in the Pine Forest.
Table 1. Number of San Jacinto high-elevation surveyed areas containing each willow species, and their observed elevation range.
| # of areas | Name | Elevation Range (feet) |
|---|---|---|
| 46 | Salix scouleriana | (4500) 6000 - 9640 |
| 24 | Salix lutea | (5400) 6600 - 8100 |
| 14 | Salix lasiolepis | < 7000 |
| 2 | Salix laevigata | < 5200 |
| 2 | Salix lucida ssp. lasiandra | < 5200 |
| 1 | Salix lemmonii | 7900 - 8000 |
The most common species above 6500 feet elevation is by far S. scouleriana. The overall abundance of S. lutea is somewhat exaggerated by Table 1, since it is mostly confined to the major creeks and we have done 15 separate surveys of 6.25 miles of Tahquitz and Willow Creeks, slicing those creeks into much smaller areas than are typical of the other surveyed locations.
This page currently shows photographs of the three species found above 7000 feet elevation, along with tips on how to distinguish them. The other three species are discussed on the Key to Willows of Coastal Southern California Below 6000 Feet Elevation. We'll eventually add pictures of those species from San Jacinto to this page, along with tips on how to distinguish them from all the other species.
The first section below shows pictures of the three species side by side. Subsequent sections are devoted to each of the species, with additional sets of pictures showing the variation in each species.
Comparison of the species found above 7000 feet elevation
We first compare the species for various characteristics in words, followed by pictures showing the three species side by side.
Distribution. S. scouleriana is widespread, found along minor to major drainages in Tahquitz, Round and Long Valleys, as well as in other areas where its roots can tap enough moisture. S. lutea is found only along Willow and Tahquitz Creeks in Tahquitz Valley next to flowing water. S. lemmonii is found only at the edges of Skunk Cabbage Meadow, and was not even known at San Jacinto Mountain prior to our surveys.
Leaves. Most leaves of S. scouleriana are obovate or oblanceolate, widest above the middle, with a rounded tip, which is distinctive when it occurs. However, S. scouleriana infrequently has narrower leaves, with an acute tip, which can easily be confused with S. lemmonii. In those cases, measuring the ratio of the length to width usually separates the two species. S. lemmonii has narrower leaves, with a typical length to width ratio of 3.3 to 5.1. S. scouleriana has a typical ratio of 1.9 to 4.1. One can get a pretty good range that will discriminate your specimen by measuring ten leaves. If you just measure one leaf, the fates almost always give you a leaf that will measure in the overlap range.
S. scouleriana also typically has minutely turned-down leaf margins, which usually requires a hand lens to see, from the bottom of the leaf. The other two species usually have flat leaf margins. (Don't confuse a serrate or bumpy edge of the leaf with the turned-down margin. The leaves of all species range from having smooth to serrate leaf margins.)
Leaves of S. lutea are distinctive in having a lighter-green, much-smoother surface, with less obvious and less deep venation, and often has very slender acuminate tips.
Stipules. S. lutea is distinctive by the presence of leafy stipules at the base of all except its oldest leaves. The other two species generally don't have any noticeable stipules at all, except sometimes for their youngest leaves, with smaller stipules than those of S. lutea.
Flowers. TBS.
Capsules. TBS.
Pictures.
Leaves
The pictures show some of the variation for each species. See the individual section for each species to see additional pictures.
Click on the thumbnail pictures to get a larger version of any of them that often includes surrounding parts.
S. lemmonii Skunk Cabbage Meadow 24 September 2010 | 
S. lutea Willow Creek 28 July 2009 | 
S. scouleriana Tahquitz Creek 7 September 2009 |
S. lemmonii Skunk Cabbage Meadow 11 October 2011 | 
S. lutea Willow Creek 12 August 2009 | 
S. scouleriana Skunk Cabbage Meadow 24 September 2010 |
Stipules
S. lemmonii Skunk Cabbage Meadow 24 September 2010 | 
S. lutea Tahquitz Creek 7 September 2009 | 
S. scouleriana Tahquitz Creek 7 September 2009 |
Pictures of buds, flowers and capsules TBS.
Pictures of S. lemmonii
Leaves
|
Skunk Cabbage Meadow 24 September 2010 | 
Skunk Cabbage Meadow 11 October 2011 |
Skunk Cabbage Meadow 11 October 2011 |
Stipules
|
Skunk Cabbage Meadow 24 September 2010 | 
Skunk Cabbage Meadow 11 October 2011 | 
Skunk Cabbage Meadow 30 September 2011 |
Buds
Skunk Cabbage Meadow 24 September 2010 | 
Skunk Cabbage Meadow 24 September 2010 | 
Skunk Cabbage Meadow 11 October 2011 | 
Skunk Cabbage Meadow 11 October 2011 |
Skunk Cabbage Meadow 11 October 2011 | 
Skunk Cabbage Meadow 11 October 2011 | 
Skunk Cabbage Meadow 11 October 2011 | 
Skunk Cabbage Meadow 25 October 2009 |
Pictures of S. lutea
|
Willow Creek 28 July 2009 |
Willow Creek 12 August 2009 |
Willow Creek 28 July 2009 |
Tahquitz Creek 7 September 2009 |
Tahquitz Creek 7 September 2009 | 
Willow Creek 8 August 2009 | 
Tahquitz Creek 7 September 2009 |
Pictures of S. scouleriana
TBS
References
Argus 2005, A Guide to the identification of Salix (willows) in Alaska, the Yukon Territory and adjacent regions
Argus 2008, A Guide to the identification of Salix (willows) in Alberta.