330 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM, 
PLATANACEAE. Sycamore Family. 
Platanus racemosa Nutt. CALIFORNIA SYCAMORE. 
Noted by us at Ensenada and on the west slope of the San Pedro Mértir Mountains, 
It grew along a watercourse at 1,080 meters elevation below Rancho Santo Tomas 
and was common along the river at 900 meters near San Antonio. Brandegee records 
it from the slopes of the San Pedro Martir Mountains. 
ROSACEAE. Rose Family. 
Adenostoma fasciculatum Hook. & Arn, CHAMISO. 
Perhaps the most abundant shrub in the Upper Sonoran Zone on the western slopes 
of the Sierra del Pinal and San Pedro Mértir mountains. East of Ensenada on open 
southwest slopes it was noted at altitudes ranging from about 300 meters up to 
about 1,800 meters, and in places probably reaches still higher. It is absent from the 
bottoms of San Rafael and Trinidad valleys, which are largely Lower Sonoran in char- 
acter, but grows on adjacent hill slopes. Brandegee records the species as far south as 
Rosario. A flowering specimen was collected east of Ensenada, May 31. The name 
“chamiso”’ is also commonly applied to the various species of Atriplex growing in 
the Peninsula. 
Adenostoma sparsifolium Torr. PALO AMARILIO. 
The Mexican name for this shrub is “palo amarillo,” the name given to Esenbeckia 
flava in the southern part of the Peninsula. It ranges irregularly over the western 
slopes of the Sierra del Pinal and San Pedro Maértir mountains. Near San Antonio 
it was observed as low as 1,020 meters and from this level upward in favorable situa- 
tions on warm slopes to 1,740 meters near Rancho Santo Tomés. On open slopes 
about Laguna Hanson, near the top of the Pinal Mountains, it is one of the most, 
characteristic species. It grows in thickets almost to the exclusion of other shrubs 
on some hillsides with a surface of loose, decomposed granite, and where the forma- 
tion changes abruptly to harder rock it may disappear almost entirely and be replaced 
by a thick growth of manzanita and Adenostoma Jasciculatum. Specimens were 
taken along the road from Ojos Negros to Alamo and between Rancho Santo Tomas 
and San Antonio. 
Cercocarpus rotundifolius Rydb. MOUNTAIN MAHOGANY. 
This mountain mahogany was common along small canyons from about 1,440 meters 
elevation on the west side of the Sierra del Pinal to about 1 ,680 meters near the summit 
of the range in the vicinity of Laguna Hanson. It grows as a shrub 3.5 to 5.5 meters 
high and, combined with Adenostoma fasciculatum and other species, forms dense 
thickets on some slopes. A specimen with the flowers dropping and the hairy fruits 
just appearing was collected at Laguna Hanson, June 2. The species was not noted 
by us in the San Pedro Mértir Mountains, but may occur there. 
Heteromeles arbutifolia Roemer. CALIFORNIA HOLLY, 
Common only locally, usually along streams or near springs, from near the Pacific 
coast up to about 1,200 meters elevation on the west side of the Sierra del Pinal and 
San Pedro Martir mountains. A specimen still retaining fruit was taken about 10 
miles east of Ensenada, May 31, and others in flower at Arroyo de Leén and San Antonio, 
July 4 and July 28. South of the high mountains of the northern part of the Penin- 
sula the California holly was not seen until we entered the Sierra de la Laguna, in the 
Cape District, where the same or a related species occurs on the upper slopes at from 
