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Carex stipata (1), C. annectens (2), and C. vulpinoidea (3). At this site C. annectens generally was growing between a population of C. stipata and a population of C. vulpinoidea, and in some ways was morphologically intermediate between the two.

I'm posting 3 "trios" of photos from this patch of low-growing, rhizomatous & cespitose Carex...found by Ellen Uhler on a grassy north-facing slope on San Bruno Mountain. The other two "trios" are here and here.

This first "trio" has the best images, though none of the photos show stigmas, a clear view of male spikelets, or various other characters. Nevertheless, with luck an ID may be possible by Carex cognoscenti (a group which doesn't include me! ;-). The 1st photo here shows the habitus of a culm; the 2nd photo shows a detail of its basal spikes (with pistillate spikelets below, and staminate spikelets above); and the 3rd a detail of the non-basal (i.e. longer-pedunculate) spike.

In the field, Ellen was thinking gestalt & morphology suggested C. brevicaulis or C. rossii were the most promising candidates...though this seemed an unusual location for the latter. (Note that C. rossii is "mostly a mountain species" and there are no records of it from San Mateo County on CalFlora or the California Consortium of Herbaria...the closest record is from northeast of Mt Diablo . On the other hand, C. brevicaulis is a more coastal central CA species, and both CalFlora and the CCH have numerous records from San Mateo County, including some from San Bruno Mountain.

Checking the Jepson eFlora Carex key the plants do seem to have a number of diagnostic characters associated with C. brevicaulis and C. rossii, including:

Leaves glabrous, "peri" (gynia) hairy (Group 2); some or all flowering stems bisexual, with both staminate and pistillate flowers; basal spikelets present; pistillate flower bracts prominently 1(3)-veined; etc.

Below are links for the descriptions of the two species:

C. brevicaulis : Jepson eFlora; FNA
C. rossii : Jepson eFlora; FNA

The two species are separated at couplet 5 of the FNA key. But I'm not clear on how to resolve the choices at that key break...as, on the one hand, in my photos the "bracts of the proximal nonbasal pistillate spikes" appear to exceed the inflorescences (which would suggest C. rossii); whereas on the other hand the pistillate scales mostly "equal or exceed the perigynia" (suggesting C. brevicaulis).

This is the 2nd of three "photo trio" posts documenting a patch of low-growing Carex on a north-facing slope of San Bruno Mountain. (One point of this post is to illustrate how easy it can be to overlook the presence of diagnostic flowering spikes for this Carex in the field!)

The 1st photo of this series shows the densely rhizomatous & cespitose growth habit of the patch. The 2nd photo is a detail from below-right-of-center in the 1st photo...where, with effort, one can make out culms with basal spikes at lower left and two longer-pedunculate spikes a bit to the right. The 3rd photo is identical to the 2nd, but includes pink arrows to the basal & pedunculate spikes.

My best shot at the species ID here is either C. brevicaulis or C. rossii. For further details...see remarks under this companion post.

Dichanthelium microcarpon x lanuginosum, possibly an introgressant rather than an F1. More similar to D. microcarpon in having glabrous spikelets, ligule either tiny or not present, mostly glabrous (except some sheaths with spreading hairs) but with bearded nodes. Bushy habit is very different from D. microcarpon. The reduced leaves are odd, as is the proliferation of cilia.

Habitat a riverscour cobblebar. Dichanthelium lanuginosum (https://www.inaturalist.org/observations/91696695) was growing in very close proximity, shown in the last photo (hybrid on left, lanuginosum on the right/in the center of the photo). Dichanthelium microcarpon was growing within a few meters of the two plants but I didn't get a photo. Dichanthelium clandestinum is very common along the river in other habitats but not present at this site; no other species seen nearby.

Pressed specimen and living collection taken.