Plant Species of San Jacinto Mountain: Allium species, onions

Plant Species of San Jacinto Mountain
Allium species, onions

Fig. 1. Left: An area of the ridge between Tahquitz Peak and Saddle Junction showing zillions of onion plants in bloom on 3 May 2011. By June or July each year, there is not a single trace of the onions left, and it looks like a barren area of decomposed granitic sand. Right: Closeup of that area, showing plants of Allium burlewii in full bloom.
Click on the pictures for larger versions. The larger version of the left picture shows a shadow of the photographer, and some Jeffrey pine cones, to give a scale.

Table of Contents

Introduction and Photographs of These Species
How To Identify These Species
Geographic Distribution of These Species
Elevation Distribution of These Species
Discussion on the Geographic and Elevation Distribution of These Species
Evolutionary Relationship of These Species

Introduction and Photographs of These Species

We had botanized the high elevations of San Jacinto Mountain for years without ever seeing an onion. On 16 July 2007, the eagle-eyed James Dillane spotted a dried-up detached onion inflorescence in two places along the PCT below the Red Tahquitz / White Tahquitz Ridge, which shocked us. We at first thought this dried-up plant probably was A. burlewii, and it turns out Hall had only seen a single dried-up plant of what he thought might be this species in his surveys, too!

We finally made it back to this location earlier in the year on 7 June 2010, and were stunned to see that the entire slope was covered with onion leaves and flowers! In fact, there were onions in the trail. We, and zillions of other PCT hikers, had been walking on the area where they grew for years without knowing the bulbs were sleeping under our feet.

However, even with fresh flowers, we couldn't definitively key these plants out to the species; they weren't perfect matches to any species description in the Jepson Manual.

The next year, in late April 2011, Dave found the same onions growing in the same barren-looking habitat on the Black Mountain Trail. This started a quest to examine similar habitats all over the mountain early in the season to see how many of them harbored onions. A lot of those spots had onions in great abundance! For example, when we surveyed for onions on the ridge between Chinquapin Junction and Saddle Junction, we quickly realized it was far easier to GPS locations without onions than to GPS all the locations with onions.

It turns out that onions are one of the most numerous plant species at San Jacinto Mountain, but you'll only know that if you botanize it early in the season; see Fig. 1.

We eventually found nine onion species at San Jacinto / Santa Rosa Mountain. Some of the onion species are distinctive at a glance in the field, but others are harder to distinguish, and require closer examination to identify them. The purpose of this page is to show our nine onion species, and point out how to distinguish them.

Photographs of the entire inflorescence of each species are shown in Fig. 2, and the names of the species are given in Table 1. The scientific name in Table 1 is linked to the online Jepson Manual eflora, and the common name is linked to pictures are Calphotos.

A. burlewii

A. campanulatum

A. cratericola

A. fimbriatum var. fimbriatum

A. lacunosum

A. marvinii / A. haematochiton

A. monticola

A. parryi

A. peninsulare var. peninsulare
Fig. 2. The nine Allium species at San Jacinto Mountain. All photos by Tom Chester except A. marvinii by Jordan Zylstra and A. monticola by Kirk Anderson. Click on the pictures for larger versions.

Table 1. The Nine Allium species at San Jacinto Mountain

Scientific NameCommon Name# of VouchersElevation Range (feet)
Allium burlewiiBurlew's onion105300 - 9000
Allium campanulatumdusky onion15600 - 8700
Allium cratericolaCascade onion114500 - 7000
Allium fimbriatum var. fimbriatumfringed onion183900 - 4600
Allium lacunosumpitted onion104200 - 5300
Allium marvinii / A. haematochitonYucaipa onion / redskin onion142400 - 5500
Allium monticolaSan Bernardino Mountain onion0 
Allium parryiParry's fringed onion74500 - 5300
Allium peninsulare var. peninsulareMexicali onion33800 - 5300

The Rest of this page has not yet been written, and just contains a shell taken from another page as a template

The elevation range in Table 1 is from vouchers; need to add our observations (guessed at campanulatum; need to look up).

Fig. 1 shows photographs of our nine species.

How To Identify These Species

Geographic Distribution of These Species

The geographic distribution of the accepted vouchers is shown for all species in one plot, for all of SnJt Mountain in Fig. 2, and for just the west side of SnJt Mountain in Fig. 3. Maps of accepted vouchers for each species individually are linked here:

Fig. 2. Geographic distribution of vouchers of the nine Allium species at SnJt.

Elevation Distribution of These Species

Fig. 4. Plot of the elevation vs. longitude for the nine Allium species at SnJt.

Discussion on the Geographic and Elevation Distribution of These Species

Evolutionary Relationship of These Species

Here are all of the San Jacinto onions that we have recorded and mapped to date listed roughly in descending
 order of the elevation at which they were found:
Burlew's onion (Allium burlewii)
Sierra onion (Allium campanulatum)
San Bernardino mountain onion (Allium monticola)
Redskin onion (Allium marvinii)
Peninsular onion (Allium peninsulare var. peninsulare)
Parry's fringed onion (Allium parryi)
Pitted onion (Allium lacunosum)
Cascade onion (Allium cratericola)
Fringed onion (Allium fimbriatum var. fimbriatum)

Voucher data provided by the participants of the Consortium of California Herbaria on .

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Copyright © 2016 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 16 April 2016.