Botany Blitz Finds Uncommon Plants in Whiting Ranch

Written by Guest Author Ron Vanderhoff

On Sunday morning, April 16, a large group of one-hundred enthusiastic OC CNPS [Orange County Chapter of the California Native Plant Society] members and friends joined our second Botany Blitz, this year at Whiting Ranch Wilderness Park.

We were nearly overwhelmed by the enthusiasm and number of participants, which included a diverse selection of expert botanists, students, land managers, naturalist volunteers, friends, and nature lovers. Participation was so strong that we had to shut down registrations a week early. 

Gathering at Concourse Park before the Botany Blitz. Ron Vanderhoff (right) and 7 botanists lead. (Photo by S. Saroa)

Each participant received a first draft of our Whiting Ranch Wilderness Park Vascular Plant Checklist

A Botany Blitz is a one-day coordinated effort to document as many plant species as possible at a given location, in this case the 2,500-acre Whiting Ranch Wilderness Park in the foothills of the Santa Ana Mts. The park was divided into seven survey areas and teams were assigned to each area. Each team was led by expert botanists, including Bob Allen, Rebecca Crowe, Joshua Der, Emile Fiesler, Amanda Fisher, Sandy Leatherman, Fred Roberts, Michael Simpson, and Ron Vanderhoff.

Documenting plants in Whiting during the Blitz. (Photo by A. Arenas)

Here are a few numbers from the day:

Plant observations: 1,714.

Individual plant taxa observed: 299 (218 native, 81 non-native).

New plants added to the Whiting Ranch Park Vascular Plant Checklist: about 20.

Newly vouchered (collected) plants added to the checklist: about 15.

Species with the most observations: Phacelia parryi – Parry’s phacelia with 31.

Some individual superstars from the day were Laura Camp and Dan Hetzel. Laura made a whopping 154 plant observations, followed by Dan with 149. For the most individual species identified they flipped order, with Dan recording 124 and Laura 112. Wow!

The Whiting Ranch Wilderness Park Checklist is a collaboration between the UCI Herbarium and OCCNPS. Begun in 2022, this checklist will include herbarium vouchers (collections) of every plant taxon at the park, with additional observations from iNaturalist and Calflora. 

UCI Herbarium samples. (Photo by R. Crowe)

Only in its first year, our project is already dramatically increasing the documented plant diversity at the park. Our total taxa (incl. species, subspecies and varieties) at the park is now 470. That is a dramatic increase from only a handful of records just a year ago, when the project was begun.

Some highlight species from both the Blitz and the Checklist Project:

        Aphyllon species – broomrape. Possibly A. californicum or an undescribed taxon.

        Arctostaphylos glandulosa subsp. glandulosa – Eastwood manzanita. A low elevation occurrence.

        Aristida adscensionis – sixweeks three-awn grass. Uncommon in OC.

        Calochortus catalinae – Catalina mariposa lily. Conservation status.

        Cenchrus ciliaris – bufflegrass. Invasive. Possibly a first OC record.

Cenchrus ciliaris– Invasive. (Photo by R. Vanderhoff)

        Chorizanthe procumbens – prostrate spineflower, uncommon in OC.

        Cryptantha muricata var. muricata – pointed cryptantha. Uncommon in OC.

        Leptosiphon parviflorus – variable linanthus.  Uncommon in OC, westerly, low elevation.

Leptosiphon parviflorus. (Photo by R. Vanderhoff)

        Muhlenbergia microsperma – littleseed muhly. Conservation status.

        Nolina cismontana – chaparral beargrass. Conservation status.

        Oenanthe sarmentosa – Orange County’s only known colony.

        Penstemon centranthifolius – scarlet bugler. A low elevation, westerly occurrence.

        Phacelia ciliata – great valley phacelia. Uncommon in OC.

Phacelia ciliata. (Photo by R. Vanderhoff)

        Phacelia hubbyi – Hubby’s pahacelia. Conservation status, uncommon in OC.

        Senecio angustifolius – New invasive in OC and San Diego Counties

This brings the Whiting Ranch Wilderness Park Vascular Plant Checklist project to the following totals:

Observations: 8,836.

6,921 iNaturalist Observations.

1,509 Calflora Observations.

406 Collections on the Consortium of CA Herbaria (CCH2).

If you want to dive a little deeper into the details of the Blitz or the full Checklist, see the individual species and observations or other details, here are a few helpful links:

The official on-going checklist, published on the CCH2 site, click HERE.

Results of only the April 16 iNaturalist Botany Blitz, click HERE.

ALL the iNaturalist observations, all-time at the park, click HERE.

ALL the Calflora observations all-time at the park, click HERE.

Want to help? Here are some ways you can assist this project.

  • Keep visiting the park and recording the plants you see. Our team is monitoring all iNaturalist and Calflora records at the park. All you need to do is take great diagnostic photographs of the plants you see and post them to either iNaturalist or Calflora. It’s free, it’s easy, and we will see them, confirm them, and include them in the checklist. If it is a species we have not yet vouchered (collected) we may contact you or return to the exact location of your record and collect a sample.
  • At your computer, review the iNaturalist observations from the park, especially those that are not yet Research Grade. Here’s a shortcut that will take you directly to the iNaturalist “Identify” page for the park. If you are certain an identification is correct “Agree” with it, if not, click on it and enter the correct identification. This curation elevates the observation to Research Grade, which is necessary to be included in the Checklist.
  • Volunteer at the UCI Herbarium (IRVC) this summer! IRVC is preparing the plant vouchers for both the Whiting Ranch and Caspers Wilderness Parks projects. We need your help in preparing these plant specimens, which will be kept safe in perpetuity and serve as verifiable records of the plants at the park. This entails neatly attaching plant specimens and their data label to archival paper. Preparing herbarium specimens is really fun and is sure to get the science and art parts of your brain active! Herbarium sessions are planned for the second Sunday and third Thursdays of June, July, and August OR until we run out of specimens (June 11th, June 15th, July 9th, July 20th, August 13th, & August 17th)! Please email Rebecca Crowe,, for more info and to sign up for a session!
Preparing plant specimens at UCI Herbarium. (Photo by R. Crowe)

We thank Whiting Ranch Wilderness Park Supervising Ranger Candice Hubert as well as the Natural Resources Staff at Orange County Parks for their full support and encouragement. They granted our permits and allowed unprecedented access to this amazing natural resource in Orange County.

One response to “Botany Blitz Finds Uncommon Plants in Whiting Ranch”

  1. For anyone wanting to dive even further into the technical parts of our surveys and work, visit our checklist project on the California Consortium of Herbaria:


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