Leaf Structure of Rhododendron catawbiense Michx. Growth in Picea-Abies Forest and in Heath Communities

Cain, Stanley; Miller, J D

During the past five years the writer has been interested in members of the order Ericales which are abundant, both as to numbers and species, in the Southern Appalachian Mountains, especially in the Great Smoky Mountains which are the highest and least disturbed. Especially interesting are the treeless communities, mainly in exposed or burred places in the sub-alpine zone, which are dominated by species of Ericales such as Rhododendron catawbiense Michx., R. punctatum Andr., R. maximum L., Kalmia latifolia L., Dendrium prostratum (Loud.) Small, Vaccinium corymbosum L., Hugeria erythrocarpa (Michx.) Small, Menziesia pilosa (Michx.) Pers., etc. A considerable quantity of material for ecological comparisons of anatomy has been collected, from which this study on Rhododendron catawbiense, and the following by Mr. Duncan, on R. punctaturm, are the first reports. The anatomical work is preliminary to physiological and transplant studies which it is hoped can be carried out in time. For that reason the relation of these xeromorphic structures to vital processes is reserved for later consideration. This study compares the leaf structure of a single species grown under the protection of the sub-alpine spruce-fir (Picea rubra-Abies Fraseri) forest, and the heath bald communities where exposure is much greater. In transitional regions, between the balds where Rhododendron catawbiense is one of the dominants in the superior stratum, and the denser, taller forest where the Rhododendron is scattered, it forms one of the dominants in the shrub stratum. These communities have been described by Davis (1930) and by Cain (1930 and 1931). The following data on the environment have been taken from the latter publications.

Leaf Structure of Rhododendron catawbiense Michx. Growth in Picea-Abies Forest and in Heath Communities

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