Yadon’s rein orchid by Dash Dunkell

Hearing the word “orchid” often brings thoughts of rain-drenched equatorial jungles, or perhaps, a coddled houseplant protected from the elements and given just the right amount of water and nutrients. However, several species of orchids grow in Central California, including delicate rein orchids in the genus Piperia.

The federally endangered Yadon’s rein orchid (Piperia yadonii) is considered endemic to northern Monterey County, growing only in maritime chaparral, Monterey pine forest and Monterey cypress forest habitats. Elkhorn Slough Foundation (ESF) has protected approximately 371 acres of maritime chaparral, over 1/3 of all the chaparral in the slough  watershed. In 2023, the US Fish and Wildlife Service (USFWS) asked for information on Yadon’s rein orchid on ESF lands. While we knew that we had several large populations of orchids, the data were scarce and many of the populations hadn’t been surveyed in years. Not long after that, USFWS announced a grant opportunity for protecting endangered species.  With help from USFWS botanist Todd Lemain to plan the research and write a grant, ESF received funding to better understand and manage the orchids on our lands.

Unlike epiphytic orchids, which grow on other plants, terrestrial orchids such as Piperia species grow in soil. In maritime chaparral near the slough, Yadon’s rein orchid grows almost exclusively in poor soils on sandstone outcrops, often in association with Hooker’s manzanita (Arctostaphy,los hookeri) or Pajaro manzanita (A. pajaroensis), two other rare chaparral species. One of the many quirks of P. yadonii is that it can only be positively identified while in flower, but not every individual plant flowers every year. An unknown proportion of each population remains underground as dormant tubers in any given growing season. Of the individuals that do emerge and leaf out in any given year, only a smaller percentage will then produce flowers and there is strong variation in flowering rate between years, populations, and perhaps even habitats.

With support from the USFWS grant, ESF stewardship staff have been surveying all our potential habitat for populations of Yadon’s rein orchid. The first surveys were conducted during the winter of 2023/24 to look for the characteristic strap-like leaves emerging from the soil, and we were very excited to find potentially tens of thousands of individuals growing throughout our network of protected lands! More surveys were conducted during summer of 2024 to look for flowering plants and make positive IDs, where we found the vast majority of orchids were P. yadonii, with a few P. elongata (aka denseflower or chaparral rein orchid).

In fall of 2024 we harvested the seed from the positively identified Yadon’s rein orchids, put half in cold stratification and half not (to hedge our bets), and then this winter mixed the seed with a little bit of soil from existing populations before spreading it in areas of good potential habitat but no existing populations of the species. The reason to mix in soil was to try and expose the orchid seeds to the necessary symbiotic fungus species which helps the seed grow without an endosperm energy reserve (orchids are very strange!). Future work on this project will include removing encroaching trees and invasive species from areas near existing populations and continued monitoring of existing populations and seeded areas.

Keep your eyes open for tiny orchids in Santa Cruz county. If you’d like to see rein orchids in their Monterey County natural habitat, Manzanita Park in Prunedale has a known population and June is often peak flowering time. Another option is to become a member of Elkhorn Slough Foundation and join special members-only hikes and tours which can include properties with the orchids and other interesting plants!

kingdom  Plantae,  phylum  Anthophyta,   class Monocotyledones,  order Orchidales,  family  Orchidaceae,  genus Piperia