April 13, 2014
First we stopped at Manzanita Point on the Catalina Highway to look at the Arctostaphylos pringlei plants there. Here, a whole hillside of A. pringlei was burned in a fire and is slowly recovering. Several of the larger plants were in bloom. There were pink flowers on some plants and white-pink flowers on others. Didn’t see any pollinators on the flowers, though there were what I think were honey bees flying around, rather aggressively. Very windy on the western side of the mountain.
Hiked the upper end of the Green Mountain Trail. Now we have been at both ends of this trail and the Bug Springs Trail. Trying to get an upper extent of both Arctostaphylos species and Arbutus arizonica in these mountains. All three species occur together at upper altitudes. A. pungens was the winner for highest elevation on this trail.
Getting an interest in silverleaf oak (Quercus hypoleucoides). In the southwest there are three main types of oak:
- Section Quercus, the white oaks
- Section Protobalanus, the intermediate oaks
- Section Labatae, the black or red oaks
Q. hypoleucoides is a black oak. The species is found in Arizona, New Mexico and Texas. The plant as a tree and sometimes as a small bush, extends further up into the forest and is more prevalent than any of the others I’ve mentioned. Like Arbutus arizonica, it occasionally gets toothed rather than smooth leaf edges. Like all other oaks, Q. hypoleucoides hosts many types of galls. Cynipid wasps induce most of a huge range of oak galls. The range of genera and species is great but in general the wasps don’t cross sections, wasps that induce galls in white oaks don’t induce galls in black or intermediate oaks and vice versa. I found a potato-shaped stem gall with many holes induced by Callirhytis quercussuttoni (proposed: Andricus quercussuttoni) in California. Note that it may not necessarily be the same species or even genus in Arizona. These wasps induce these galls during a bisexual generation, producing both males and females. During a unisexual generation the wasps induce galls in the leaves. I spotted another type of gall on the leaves induced by a erineum mite (Eriophyes mackiei). These mites are one of the few gall inducers on oaks that are not cynipid wasps and are unique because they use as hosts to both black oaks and intermediate oaks (Russo, 2007) (Weld, 1960).