212 Flora of Bouldin /sland. [ZOE 
the bottom of the river, and is added to year by year, as it is con- 
stantly sinking. Both sides of the levee are fringed with a dense 
growth of willows, alder, and the ever present ‘‘Tule.’’ The 
land slopes to the centre and is irrigated by means of guarded 
openings in the levee, care being taken not to admit an undue 
quantity of water. The island is dry on the surface for the most 
part, although the water is but a short distance beneath, and the 
winds often raise the light loam from the roads in swirling clouds 
of dust. The ground shakes very perceptibly from the passing 
of wagons, and in many places even from a footstep, a peculiar- 
ity which is somewhat unpleasant until custom has rendered it 
familiar. 
The natural flora of the islands embraces but few species as 
would naturally be expected from the sameness of environment. 
It consists besides the prevailing ‘‘ tules "’—Scirpus lacustris and 
S. Tatora—in great part of Psoralea macrostachya, Epilobium 
holosericeum, Solidago occidentalis and S. elongata, Baccharts 
Douglasti, Helianthus Californicus, Artemisia vulgaris, Apocynum 
cannabinum, Convolvulus Sepium, Stachys albens, Polygonum 
Flartwrightii, Urtica holosericea, Alnus viridis, Salix longifolia & 
S. sessilifolia, Typha latifolia, Cyperus erythrorhizos, Phragmites 
communis, etc. The leveed islands abound in weeds as may be 
seen from the list appended. Their luxuriance in most cases far 
exceeds anything seen on the mainland, and the species are 
usually well diffused. The vegetation is late, the time of fullest - 
flowering being in August and September. 
The entire absence of many of the large genera and even 
families of Californian plants of the not distant mainland is very . 
noticeable. Aanunculus aguatilis is the only plant belonging to 
that family to be expected, and even that has not been collected — 
on Bouldin Island. There are no Caryophyllaceze except a stray 
Stlene Gallica or Stellaria media, no violets, no Saxifragacez, no 
Hydrophyllacez, no Polemoniaceze except an occasional recently 
immigrated Gi/ia sguarrosa, not a single Hemizonia or Eriogonum, 
and no plant belonging to the Orchidaceze, Iridaceze, or Liliacez, 
unless Lilium pardalinum should be found to occur in some 
places. 
The list below is the result of a visit to Bouldin Island, Sep- 
