THE NATURE OF THE FLESHY SHOOT OF ALLENROLFEA AND ALLIED GENERA

Abstract

James, Lois E. (Whittier Coll., Whittier, Calif.), and Donald W. Kyhos. The nature of the fleshy shoot of Allenrolfea and allied genera. Amer. Jour. Bot. 48(2): 101–108. Illus. 1961.—A number of genera of the Chenopodiaceae are characterized by what have been called fleshy internodes which make them appear jointed. The fleshy tissue comprises on the average the outer ⅔ of what superficially appears to be the stem. This fleshy tissue contains a vascular network which is continuous with and similar to the vascular network in what has commonly been called the scalelike leaf. The problem is whether this fleshy vascularized tissue is the result of a downward prolongation of the base of the leaf or whether it is actually the true cortex of the stem. The present authors have found that Allenrolfea is uniquely suited to solving the problem of the so‐called fleshy internodes of these allied genera. The origin and development of the fleshy tissue indicate it to be foliar. This conclusion is further substantiated by the shape of the fleshy tissue, its phyllotactic arrangement, the extent of the palisade tissue and underlying vascular network, the pattern of branching of the leaf traces, and the effect of secondary thickening and suberization.