Plant Species of San Jacinto Mountain:
Epilobium angustifolium = Chamerion angustifolium, Fireweed

Fig. 1. Top and middle rows: Fireweed in Tahquitz Creek photographed on 17 August 2009. Bottom row: Fireweed in Willow Creek photographed on 28 July 2009. Click on the pictures for larger versions.

Fireweed is a circumboreal species in the Evening primrose family, Onagraceae. It is sometimes seen as vast fields in the far northern latitudes of the world. The San Jacintos are not the southernmost extent of the range of fireweed but nearly so. Perhaps at these southern latitudes it is too arid for the mass displays of blooms seen to the north.

The scientific name of fireweed used in our flora is Epilobium angustifolium ssp. circumvagum, which is the name used in the printed versions of the Jepson Manual. The latest name for it is Chamerion angustifolium ssp. circumvagum, used in the Jepson eflora.

There are two recognized subspecies of fireweed that overlap geographically to a large degree. In North America ssp. circumvagum ranges farther southwest than ssp. angustifolium, and is the only subspecies found in California.

In the San Jacintos fireweed is confined to the high elevation riparian areas of the mountain.

In his 1902 publication A Botanical Survey of San Jacinto Mountain, Hall wrote, "Found only along Tahquitz Creek at 8300 ft. alt." He was also the first to voucher it in the San Jacintos in 1899. In addition to Hall there are three other vouchers on the Consortium of California Herbaria with the last one being in 1928. One is said to be from Round Valley, and two are at Deer Springs which is actually the Deer Springs Camp on the trail to the summit of Mt. San Jacinto. We have surveyed Round Valley extensively, and have not found this species there, nor has anyone else. We suspect that collection was actually from either Deer Springs Camp, which is on the trail toward Round Valley, or Tahquitz Valley.

During our Lemon Lily Census of Tahquitz Valley in 2009, we found fireweed growing with lemon lily in every one of our 15 segments, with a total of a minimum of 398 plants seen in 45 places, but we seldom saw them in bloom. As conspicuous as the blooming plants with their magenta flowers along tall erect stems are, non-blooming plants can be difficult to spot. We sometimes wondered if we were confusing young willows for non-blooming fireweed; see Fig. 1 bottom right photograph. This may explain the low reporting rate for fireweed in the San Jacintos.

The 398 plants seen in our survey of Willow and Tahquitz Creeks ranks fireweed as the 37th most abundant species of the 185 on the  list, just making the most abundant 20% of the 185 species. Fireweed is in the select group of just 16 species that were found  in all 15 segments.

We also found fireweed in Candy's Creek in Tahquitz Valley, and in the North Fork drainage including the Marion Mtn Trail to Deer Springs Campground; the PCT from the Marion Mtn Jct to the Fuller Ridge Junction; the 7 Pines Trail area; and the Fuller Ridge Trail.

Fireweed as the name implies is known to be a fire follower. It would be interesting to see what effect if any the 2013 Mountain Fire had on the fireweed population.

Go to:

Copyright © 2018 by Dave Stith and Tom Chester.
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 1 May 2018.