Arctostaphylos otayensis

A gorgeous shrubby tree manzanita. Similar to Arcto. manzanita Dr. Hurd' but more open. Native in the San Diego area in chaparral. Associated plants include Keckiella ternatus, Keckiella antirrhinoides microphylla, Arctostaphylos glandulosa Adamsii, Prunus fremontii, Quercus agrifolia, and believe it or not Acacia greggii. Soil varies from reddish clay to decomposed granite. The Otay Manzanita was about 15 ft. tall, with a 6 inch red trunk.
"Bombus edwardii had a thoracic temperature of 37C{100F} while foraging at 2C {35F} from a manzanita, Arctostaphylos otayensis, an energetically expensive operation. However each flower contained 1.5 cal of sugar while the maintenance cost was about .8 cal/minute, so that the bees could make an energetic gain while foraging at near freezing temperatures. At noon when the flowers were visited by small insects each flower contained only .32 cal of sugar. Thus it may be energetically most profitable for the bees to forage in the early morning when there is either little competition for nectar, a considerable accumulation of nectar, or the rate of nectar secretion is high." (Heinrich and Raven, 1972 as quoted in Price, Peter 1975)