Help with ID on intriguing plant
Hi,
For over a year now, I have been intrigued by this small plant that I found in the Bay Area. It is something that I have only found in 2 locations that are in close proximity to each other. So far, the best ID I could get on iNat is "Vascular Plants". I have checked with a number of my friends, who are very knowledgeable about local flora. I even checked with the park's environmental scientist. None of them have an idea what it is. Is it something rare? Interesting? (Definitely interesting to me!) New?
Any help is appreciated.
The plant consists of a stalk with no leaves and one to several flowers. The 7 to 10mm flowers only open when they are wet (rain or heavy fog). When they are dry, the flowers close completely, making the plants nearly invisible and impossible to locate. Most of the flowers show no sign of reproductive organs. Only a few develop what look like round stones. The plants emerge with the first rains (this year in October) and are gone when the rains end (last year, by March). Oddly, I only find them on the trail, never off the trail, even near where the population is quite dense. This makes it seem like they require the ground to be scraped or very compacted.
I have been visiting them on a weekly basis and charting the weather conditions, to see when they bloom. It turns out that they just have to be wet. When I put a few drops on a closed plant, it opens within about 15 minutes.
Any help is appreciated!
@kueda
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Observations
Photos / Sounds
What
Hill Sun Cup (Tetrapteron graciliflorum)Observer
kendalloeiDescription
Or, at least I think it's a fungus. Or tiny flower?
Photos / Sounds
What
Hill Sun Cup (Tetrapteron graciliflorum)Observer
kendalloeiDescription
Really needs ID!
For over a year now, I have been intrigued by this small plant that I found in the Bay Area. It is something that I have only found in 2 locations that are in close proximity to each other. The 7 to 10mm flowers only open when they are wet (rain or heavy fog). When they are dry, the flowers close completely, making the plants nearly invisible and impossible to locate. Here's an observation with the flowers closed.
https://www.inaturalist.org/observations/104899181
So far, the best ID I could get on iNat is "Vascular Plants". I have checked with a number of my friends, who are very knowledgeable about local flora. I even checked with the park's environmental scientist. None of them have an idea what it is. Is it something rare? Interesting? (Definitely interesting to me!) New?
Any help is appreciated.
Photos / Sounds
What
Hill Sun Cup (Tetrapteron graciliflorum)Observer
kendalloeiDescription
Really needs ID! For over a year now, I have been intrigued by this small plant that I found in the Bay Area. It is something that I have only found in 2 locations that are in close proximity to each other. The 7 to 10mm flowers only open when they are wet (rain or heavy fog). When they are dry, the flowers close completely, making the plants nearly invisible and impossible to locate. Here's an observation of it with flowers open.
https://www.inaturalist.org/observations/104899180
So far, the best ID I could get on iNat is "Vascular Plants". I have checked with a number of my friends, who are very knowledgeable about local flora. I even checked with the park's environmental scientist. None of them have an idea what it is. Is it something rare? Interesting? (Definitely interesting to me!) New?
Any help is appreciated.
Photos / Sounds
What
Hill Sun Cup (Tetrapteron graciliflorum)Observer
kendalloeiDescription
1st observation of the year in 2021
Comments
Cool. I'll add @catchang to your list.
Thanx Dan!
Fascinating! I think the structures there might actually be the seed pod of the plant. @rupertclayton Any thoughts here?
Not sure what this is. @graysquirrel is on to something with her suggestion this is the fruit capsule. @jdmore might know.
Odd, though, that they would open whenever wet, even without the presence of any seeds to disperse. My first thought was that they were a fungus, reproducing like Bird Nest Fungi, but the stem is very woody. I've never seen any leaves or anything that looks like a flower, other than this structure.
Not ringing any bells here. Odd indeed! I see that all of your observations so far are in January. Are you able to follow them through other times of year to see if any other structures show up? (I agree this seems like a fruit, and not unusual that it would continue to respond to changing humidity after seed dispersal - think of pine cones for example.)
Any ideas? -
@dhwilken
@fmroberts2
@jdjohnson
@jrebman
@keirmorse
@kgferg
@klazar
@matt_g
@naomibot
@randomtruth
@sedgequeen
Add me to the list of clueless but intrigued.
Discovered them in January of last year, then got redirected to monitoring Peregrine Falcon nests in February. This year, I have observations from 10/31 to 1/9. Looked similar throughout this period. Perhaps I didn't recognize them prior to 10/31, because pods hadn't developed yet...? PEFA nesting season is approaching, but will see if I can continue to check once every few weeks.
I just added an observation for 10/31. https://www.inaturalist.org/observations/105089311
Note that they are shorter, as if recently emerged. Also, they are full of gravel, as if they came up open and scooped it up or grew around it.
Can you give more info on location? IE, is this at the base of the escarpment to Castle Rocks? Or directly in a trail?
Hi Cat, I PMed you.
I've seen these before in the Tehachapis. I believe they are the fruits of Tetrapteron. In our area that would be T. graciliflorum.
I would agree with @randomtruth that they look a lot like the hygrochastic capsules of Tetrapteron
Some photos on Calphotos:
https://calphotos.berkeley.edu/cgi/img_query?stat=BROWSE&where-genre=Plant&where-taxon=Tetrapteron+graciliflorum&title_tag=Tetrapteron+graciliflorum
I'm kind of sad a couple people already figured it out. It would have been more fun if we were all clueless.
I would never have gotten this! It looks like @randomtruth and @jrebman have the solution. Tetrapteron graciliflorum is the species that's present in the Bay Area. Tetrapteron was previously a section with Oenothera and was elevated into its own genus in 2007. I assume that the name (lit. "four winged") was given for the unusual capsule. The sister species T. palmeri was cited as an example of delayed seed dispersal in California desert plants in this 2015 paper: https://www.biodiversitylibrary.org/item/265709#page/23/mode/1up
I assume that the physical processes causing the hygrochastic opening of the woody capsule are independent of whether any seeds remain. Presumably most seeds got washed out during the major storm on 10/25–10/26 but the capsules keep opening and closing regardless. The paper mentions that "Old skeletons, at least one year old, have been observed and collected in the field."
Very cool! Thanx to everybody who pitched in! I see two observations by others on Mount Diablo and a fair number along the Diablo Range. Will try to follow up with pictures when they REALLY bloom, for my own info and enjoyment. This was a great mystery! Thanx again!
Found it. Here are photos I took in the Tehachapis of what is probably T. palmeri:
https://www.flickr.com/photos/randomtruth/7025500347/
Note the seeds still inside in March. I believe at that elevation the pods stayed closed under the snow and then opened with the thaw.
I think you nailed it @randomtruth, good call!
Fantastic- this species is somewhat under reported. Thanks for all the input.
Under-reported and perhaps Locally Rare for the SC Mtns bioregion. I've only seen T. graciliflorum at Edgewood Preserve and Santa Teresa CP. And I think it's also know at Almaden Quicksilver. But perhaps it's also a fire-follower that generally declines and disappears, except in areas where heavy disturbance germinates a few seeds each season. Such as along roads from use and brush-cutting. We see this locally in the SC Mtns with other annuals that are chaparral associates, such as Monolopia gracilens.
Wow!
I added the observations of my mystery flower when it's actually in bloom. Tetrapteron graciliflorum, what a beautiful flower!
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