Plant to Ecosystem Science

Identifying the what, where, and why of OC plants and special places

By the

Orange CountyCalifornia
Land Area2,070 sq km403,932 sq km
Native Plants, Calfora1,4138,192
Rare and Imperiled (G1, G2 rank),
CNPS Rare Plant Inventory
Non-Native Plants, Calflora7212043
Cal-IPC Listed Invasive Non-Native, Cal-IPC 194
(SW CA Floristic Province)
Butterflies and Moths Attracted to Local Vegetation (approximate), Calscape3001350
Floristic Provinces, Jepson Herbarium1:
(Mediterranean climate)
Great Basin,

Wildflowers of Orange County and the Santa Ana Mountains

This is THE book of flowering plants in Orange County with over 600 species described. It contains sections on botany, geography, plant communities, and plenty of photos to help with identification. Allen and Roberts are two of our region's top field botanists/biologists. This book was published with support from our chapter.  

Holy Fire Research

On August 6, 2018, a wildfire ignited in Trabuco Canyon. The blaze burned 23,136 acres. Botanically, this fire was a significant event as much of the forest had not burned for 31 to 64 years or longer. Our chapter Rare Plant team petitioned the U.S. Forest Service for access permission and collection permits. This report describes their first year of explorations and findings, including 1,443 plant records, recovery progress, rare plants, and non-native plants.  


This grant is awarded annually to graduate and undergraduate students planning to conduct field research related to biology, ecology, floristics, taxonomy or ethnobotany of native plants.

For more information see our Education/grants page.

Grant Award Winners 2022

MARI COOKSON: Genomic investigation of the systematics and diversification in North American dwarf mistletoes (Arceuthobium ssp.)
XINU LI: Assessing plant pollinator interactions within a wildfire context.
ELIZABETH HERMAN: Assessing beach wrack ecology at Crystal Cove State Park. 

The CNPS BIG-3 Public Databases

CNPS Rare Plant Inventory

The Inventory of Rare and Endangered Plants started as deck of notecards in the late 1960's. It was a published book by 1974. After six book editions, the easily searchable online version took over. The photo above is Allen's Daisy, found only in Orange County.


Often used in the Gardening community, Calscape contains extensive information of interest to the science minded as well. Locations with herbarium specimens are marked and areas of local similar characteristics are highlighted. You will often find data for climate, site type, soil, dormancy, and wildlife supported including tremendous butterfly-moth associations. As with all of the CNPS online databases, Calscape has an easy to use, powerful, advanced search option.    

Manual of California Vegetation

The MCV is your portal to a treasure of California vegetation survey information standardized for easy searching. Look up which plants are found together in repeating patterns across the landscape. These plant groupings are called alliances. Find out where alliances occur and their characteristic soil, water, disturbance, and fire environment.  

More Data

Intro to Studying OC Plants

Here is Bob Allen's quick introduction to key geographical features and resources for study. People who scan to the third and final page are treated to a short list of 4 plants found only in Orange County or the Santa Ana Mountains. 


Favorite Resources

The CNPS Big 3 public databases will take you far, but you are likely to want more information. Fortunately the plant community is larger than many expect. We have links and brief descriptions of the most useful and a few other favorites. 

Floras, Plant Lists, Surveys...

What is a regional Flora? Did anybody identify the biological natural resources in Laguna Beach 40 years ago? What might I see while walking in the San Mateo Wilderness or Upper Newport Bay? Click above for answers and treasured plant lists.