Plant Species of San Jacinto Mountain: Juncus effusus, Pacific rush

This page is mainly just a place-holder for pictures of this species taken on 1 November 2008 on the Cedar Spring Trail, with some additional information. Abundance and locality information will be added in the future.

Two plants are shown below, one off-trail along the East Canyon Branch of Morris Creek, and a much smaller plant along the Cedar Spring Trail at mile 0.97, about 0.3 miles farther up the trail. Amazingly, both plants key from my pix of them, using Munz 1974:

1'  perennial
7   inflorescence lateral
8'  flowers inserted singly, each with a pair of bractlets at base
10' flowers many
11' stems terete; not J. mexicanus
12  perianth ~2.1-2.2 mm
13  capsules obovoid, not apiculate  ... J. effusus

These plants are usually ascribed to var. pacificus, although the current fashion is to call them ssp. austrocalifornicus. The Jepson Interchange says that ssp. austrocalifornicus is an unnamed variant mentioned as possibly warranting varietal status under Juncus effusus var. pacificus in The Jepson Manual [Ed. 1].

However, the Flora of North America treatment does not recognize varieties, saying:

The Juncus effusus complex has been variously recognized as containing several species or a single species with numerous infraspecific taxa. Unfortunately, North American treatments have dealt primarily with taxa in either the eastern or western portions of the continent. In considering the continent as a whole, little sense can be made of these treatments. The North American J. effusus complex is one that is in obvious need of modern systematic scrutiny.

Until the new Jepson Manual comes out, for the plant trail guides and floras of San Jacinto, I'll keep this under the name of var. pacificus to be consistent with the current Jepson Manual and because that is the most common name used in southern California references.


Plant found off-trail along the East Canyon Branch of Morris Creek:

Single plant amidst fallen leaves of velvet ash, Fraxinus velutina, with a dead California thistle, Cirsium occidentale var. californicum in front of it. Morris Creek is immediately behind the plant.

Single plant along Cedar Spring Trail, mile 0.97, with folded sheet of 8.5 x 11 inch paper(11 x 5.5 inches) as scale:

Leaf tip was probably broken off by trail traffic, which includes cows:

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Copyright © 2008 by Tom Chester.
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Updated 3 November 2008.