National Herbarium. He considered it an undescribed genus and named
it Ectosperma alexandrae. When in 1963 it was found that the same generic name
had previously been used in 1803 for a group of green algae, the grass was
renamed Swalienia alexandrae by Soderstrom and Decker. (Pavlick, 1979). Its
exact placement in relationship to other grasses is yet to be determined. One
can only guess as to whether it developed within the limit of that specialized
habitat, or whether it was once more widespread. At the present time only four
populations are known, all in Eureka Valley in relatively deep sand. Three of
the populations are in lesser dune areas: (1) at the sand covered ridge west of
the main dune system, beyond the playa, (2) at the mouth of Marble Canyon, and
(3) in a pocket of sand on the northern end of the Saline Range. By far the
best and largest population is on the massive sand mountain where the grass
grows within 150 feet of the crest. It is thought that its survival depends on
that site. It forms large clumps as the sand is stabilized over and around
them. These may spread as new culms grow from buried stems. They have the
ability to root at the leaf nodes as well as to propagate by seeds. The
grass is a coarse perennial, the flowering culms 6 to 20 inches tall, with
stiff, lanceolate leaves, the blades 1 to 41/2 inches long, pungently tipped.
The panicles, which develop from April to June, are 2 to 4 inches long. The
grass is distinctive, its appearance unlike any other in the region. The steep
dune slopes dotted with dunegrass hummocks are unusual. No other dune growth is
known to have become established in pure sand to such heights. The annual
Dicoria is an occasional exception. A second endemic plant is the Eureka
evening primrose (Oenothera auita ssp. eurekensis). It was first collected by
Munz and Roos in 1954. It too has been the subject of considerable study in an
effort to determine the most appropriate classification for its unique
combination of characteristics. It is a perennial which adapts to an unstable
sand surface by developing new rosettes from the nodes of buried stems.
Although dependent on the sand dunes of Eureka Valley, it does not occur high
on the dune slopes. Its main habitat is on shallower sand sheets around the
perimeters, often well away from the slopes. The most extensive population is
east of the seif. On favorable years in May the sand sheet there is dotted with
white blooms for perhaps half a mile. Being verspertine, the evening primrose
is at its best in the evening and early morning hours when its fragile white
flowers are fresh and fully open. In the morning one may find remnants of its
petals at rodent holes. |
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A third endemic plant is
the Eureka locoweed or milk-vetch (Astragalus lentiginosus var. micans). Among
their collections in 1954, Munz and Roos had a robust perennial Astragalus
which R. C. Barneby determined was a variety of A. Ientiginosus. He named it
var. micans because of its "shining, silvery vesture". It, too, occupies the
sandy perimeters of the dunes, but usually in somewhat deeper sand than the
evening primrose. Its best development has been about the northern end of the
seif. Young plants are silvery-green and vigorously bushy, becoming rather
scraggly on maturity. They have a habit of putting out new shoots during the
summer to begin a renewed period of blooming in the fall. The flowers vary from
whitish to lavender, but are less conspicuous than the inflated pods which
usually angle upward. Interesting paragraphs could be written about each
dune plant, but we will mention only a few. Clarke's dicoria (Dicoria canescens
ssp. clarkae) is a frequent associate of dunegrass and may even go above it in
some places. It is of considerable value in the dune's ecological system
because it matures in the fall and thus provides seeds for food into the
winter. String plant (Tiquilia plicata) is a small perennial which is
abundant on the sand sheet. Each plant is attached to a branch of a slender,
dark, stringlike root up to a foot long. At the end of the "string" is a fleshy
cylinder 1 to 2 inches long. This appears to act as an anchor, while the
tethered plants are allowed to move freely with the blowing sand. It is a
favored food of the desert iguana (Dipdodaurus dorsalis). Indian rice-grass
(Oryzopsis hymenoides) is a common and widespread grass which grows in
abundance on the sandy dune borders. An almost |