What a Rush! Collecting Juncus digitatus in Nevada County 

By Angela Pai

Seed banking California’s rare flora is one of the important projects that we work on in the Rare Plant Program. CNPS is one of many partner organizations participating in California Plant Rescue. Our mission is to collect seeds of rare plants and store them offsite in seed banks as a backup in case of extinction, while also gathering data about wild populations.  

On June 10, I drove out to Nevada County (Nisenan Territory) to meet Redbud Chapter President Shane Hanofee and California Floristics Specialist David Magney. Shane had spotted one of my targets for seed collection just two weeks earlier and kindly offered to take us to the population.  

Named for its distinctive fruits, the finger rush, Juncus digitatus (CRPR 1B.1), grows in vernally moist microhabitats and stands only a few centimeters tall. It is delightful to behold, if you can find it.  

Yellow finger rush flowers
Finger rush (Juncus digitatus) in flower in Nevada County in mid-May; Image: Jennifer Buck-Diaz

Just a few dozen steps away from a large intersection, we counted about 500 hundred of these tiny plants in an area of about 30 square meters. David had already obtained permission for CNPS to collect this plant, and our timing was perfect—nearly all the plants had mature fruits that were ready to gather.   

Rare plant finger rush with brown skinny fruits with outlines of seeds viewable
Finger rush (Juncus digitatus) with actual finger for scale. These fruits are perfectly ripe and ready to collect. If you look closely, you can make out the outlines of the seeds; Photo: Angela Pai

As far as we know, the finger rush (CRPR 1B.1) exists only in Nevada County, El Dorado County, and two sites in Shasta County, where it is threatened by ornamental rock mining and altered hydrology.  

About the Nevada County population, Shane notes, “I don’t have high hopes for the long-term survival of this population as it’s located in an area that is rapidly being developed at an almost constant rate.”  

Indeed, any development upslope from this population can change the hydrology of the site and destroy its sensitive microhabitat. Knowing that made this collection feel especially urgent. Shane also pointed out invasive plant encroachment and nearby dumping. 

“My only solace is the likelihood of other populations existing elsewhere, hidden by their small size and nondescript appearance,” says Shane.  

Shane pointing down to population of finger rush
Redbud Chapter President Shane Hanofee points to finger rush (Juncus digitatus); Image: Angela Pai

After seeing this plant in person, I’m inclined to agree. The tiny annual is easy to miss and seems to have a small window during which it is detectable. Both David and I have searched for this population before, but we were either too early (April) or too late (July)—or perhaps our eyes simply failed us because we didn’t find any trace of the plant.  

The Nevada County population was first documented in 2011, and the El Dorado population just in 2019. I’m optimistic that more populations of Juncus digitatus will turn up, but in the meantime, at least we have the seeds, just in case. 

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2 Comments

  1. Hello,
    Could you give more detailed information about what is a ‘vernally moist microhabitat’ so people can be alert to possibly finding a population of this tiny gem?

    Thanks

    Reply

  2. Vernally moist means that the soil is saturated for a relatively short part of the year. Much like a vernal pool. It differs from wetlands like freshwater seeps and riparian communities which tend to be perennially moist. From the photos, it looks like clay lenses/soils are the key.

    Reply

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