246 BARTRAM: BOTANIZING IN SOUTHERN ARIZONA 
RUTOSMA PURPUREA Woot. & Standl. Frequent on banks of the 
arroyos west of Tuc 
POLYGALA MACRADENIA Gray. Confined to a rocky hillside near Picture 
Rocks. . 
UPHORBIA CAPITELLATA Engelm. Forming —— showy mats on ledges 
and in crevices along the arroyos west of Tucson 
EUPHORBIA PEDICULIFERA Engelm. A ae with densely glandular 
pubescent stems and leaves is not uncommon 
EUPHORBIA POLYCARPA Benth. This and the two preceding species 
of the genus are freely distributed over the arid ridges and talus slopes. They 
all belong to the group of perennials with entire pubescent leaves and vary 
considerably in habit and appearance. 
DITAXIS NEOMEXICANA (Muell. Arg.) Heller. The lax straggling habit 
of this species is very different from the stiff erect form of D. sericophylla. 
DITAXIS SERICOPHYLLA (Gray) Heller. With the preceding on rocky 
slopes at Robles Pass. 
CALLITRICHE PALUSTRIS L. In shallow water at the mouth of Sabino 
Canyon. 
SIMMONDSIA CALIFORNICA Vutt. A striking cea: bush of the dry 
plains and goers with leathery leaves and yellow flowers in drooping 
axillary clusters. 
Doponaka viscosa L. Abundant along the stream bank in the mouth 
of Sabino Canyo 
CONDALIA SPATHULATA oe: Banks of arroyos near the foothills. 
Leaves and fruits persisten 
RHAMNUS TOMENTELLA one Ledges in Sabino Canyon at about 
3000 feet elevat 
HIBIscus else Harv. Flowering sparingly through the winter. 
: HIBIscus DENUDATUS Benth. The pale almost leafless stems and 
cae tinted pink flowers give this plant an attractive personality. Rare 
n slopes at Robles Pass 
GAYOIDES CRISPUM (L.) Small. Frequent on rocky slopes. 
ABUTILON INcANUM (Link) Sweet. Common on rocky hillsides. Leaves 
and carpels persistent. 
SPHAERALCEA AMBIGUA Gray. A polymorphous species widely scattered 
over the region. Flowezs white or pink and leaves varying greatly in outline. 
' SPHAERALCEA GROSSULARIAEFOLIA York. On rocky slopes at Robles Pass. 
ERMANNIA PAUCIFLORA S. Wats. Confined to rocky slopes near the 
mouth of Sabino Canyon. 
,_  AYENIA PUSILLA L. Frequent on the dry gravel plains. 
FOUQUIERIA SPLENDENS Engelm. Although the | ll developed 
in sunny sheltered places no flowers were in evidence by the end of Jan uary. 
OpunTIA FULGIDA Engelm. Common on the plains. 
