Morphological development of the fruit ofJuglans regia

Abstract

does not appear. First page follows. Introduction A major portion of the literature concerning the floral morphology of Juglans regia L. was published in the latter part of the Nineteenth Century and early Twentieth by French and German workers. Hicoria pecan, on the other hand, has been investigated within the last five to eight years by English and American workers. Van Tieghem,(15) the first to publish on the morphology of Juglans species, was interested in proving, to uphold his theory of parietal placentation, that the orthotropous ovule of the walnut is really an anatropous ovule, inserted on a single edge of one of the two sporophylls of the pistil. He used the vascular anatomy in this work and thus reported the number of bundles arising from the floral pedicel and the branches resulting from them. Errors have been found, especially in his interpretation of the ventral carpellary system. He also studied abnormal fruits to show that at one time in the phylogeny of the fruit there were four anatropous ovules, three of which have since aborted, leaving only the ovule traces to indicate their previous existence. He reported, therefore, that four ovule branches arise from each of the four marginals, but only one terminates in the ovule. The other three are the traces to his so-called “aborted ovules.” No other workers have reported this condition except Benson and Welsford,(2) who agree with him in all respects. They consider the placental bundles as built up of leaf traces diverging at the base of the flower and depict fruits with the two placental bundles of unequal size. They have, however, no illustrations of the three nonfunctional traces, but merely agree with Van Tieghem’s explanation of such a situation.