_Frangula Californica_ Gray. CALIFORNIA BUCKTHORN. Very common, variable, four to ten feet high; evergreen, gregarious, in clayey soil. _Ceanothus thyrsiflorus_ Esch. CALIFORNIA LILAC. Very common, and variable in size, sometimes handsome trees; exceedingly gregarious, forming dense chaparral, on the northern and eastern slopes of hills and mountains; evergreen. Much cultivated on account of the profusion of its fragrant flowers, and the various shapes that may be given it by trimming. _Ceanothus rigidus_ Nutt. Low, straggling, four to six feet high, less gregarious than the former; on the white sand-stone hills, east of Oakland. _Ceanothus ——._ A small shrub, three to four feet high, with very small glandular leaves; mostly single or in groups, on Mount Tamal Pais at 2,700 feet elevation. _Lupinus albifrons_ Benth. SILVER-LEAVED LUPINE. Very common in almost pure sandy soil, oblong in outline, two to six feet high; growing mostly single, evergreen. _Lupinus macrocarpus_ Hook. and Arn. YELLOW LUPINE. Large, spreading, oval in outline, evergreen, with large fragrant flowers; gregarious in moist gravelly places along the shore of the bay, and in depressions, or banks of runs, where the soil partakes of a clayey nature. _Pickeringia montana_ Nutt. Large, spreading, four to seven feet high; evergreen, and gregarious on the Oakland white sand-stone hills. _Cerasus Ilicifolia_ Nutt. CALIFORNIA CHERRY, or PLUM. A small tree, eight to fifteen feet high, with thick, shining, spinously serrate, evergreen leaves; fruit of a yellowish pink color, with a thin pulpy external portion. Hill sides on the peninsula of San Francisco, growing mostly in groups; rare. _Cerasus serotina_ Ehrh. BLACK WILD-CHERRY. A group of three or four small trees, eight to twelve feet high, near a road in the Oakland hills. Undoubtedly introduced from the Atlantic States. _Cerasus emarginata?_ Dougl. A small shrub, three to four feet high, with very slender reddish and white dotted branchlets, and deciduous leaves; rare. Tamal Pais, 2,700 feet elevation. _Nuttallia Cerasiformis_ Torr. and Gray. Oblong in outline, four to six feet high, deciduous; common on the northern slopes of hills, in clayey soil. Along the bay and Oakland hills. _Spiræa Opulifolia_ Linn. NINE-BARK. Large, spreading, eight to fifteen feet high; common on the banks of creeks among the Oakland hills. _Spiraea Ariæfolia_ Smith. Common on banks of creeks and northern slopes of hills, Oakland. _Cercocarpus parvifolius_ Nutt. Rare, on the hills in Marin County. Its spirally-tailed seeds give the shrub an appearance as if in full blossom. _Adenostema fasciculata_ Hook. and Arn.