Despite being one of the most accessible and well-visited state parks in San Diego County, Torrey Pines State Natural Reserve is biologically isolated, sitting between the Pacific Ocean and the urban development of La Jolla. In addition, Torrey Pines State Natural Reserve supports one of the nation’s rarest pine trees, Pinus torreyana ssp. torreyana, and an ever-growing list of unusual and rare plant taxa. How do we make sure that list continues to grow and becomes increasingly well-documented? Just call on the botanists at the San Diego Natural History Museum.
With just six field visits in 2023 and a deep dive into specimen- and photo-based collections, Curator of Botany Dr. Jon Rebman and Research Associate Margie Mulligan added 85 new plant records (an increase of 13.5%!) to California State Parks’ plant checklist for the Reserve, investigated occurrences of unusual plant taxa, and documented seven rare plant species. Of the 85 new plants, 55 were documented with specimens collected during our field surveys, and another eight were found by searching historical voucher specimens within our own museum walls (in the San Diego Herbarium). Twenty-two of those new plant species were added after Dr. Rebman personally reviewed and verified thousands of iNaturalist observations.
The recently collected voucher specimens will shed some light on unusual plants that occur within the Reserve. Rhamnus, Erysimum, and Galium specimens may represent new or intermediate species, or just newly found morphological variation within a known species.
Our discovery of Sphenopholis interrupta ssp. californica within the Reserve increases our understanding of this extremely rare annual grass. (This species was recently rediscovered after being “lost” for more than 100 years and thought to be extinct!) While usually found on heavy clay soils, we found it growing along a trail in mostly sandy soils, suggesting we may need to search for this species in more places than previously thought.
Not only is our work increasing the known biodiversity within the Reserve and adding to the understanding of unusual and rare species, the 239 herbarium specimens collected by Museum staff and volunteers are crucial for verifying species occurrences, providing vouchers for future research, and preserving genetic material.
