The hypodermal zone in the testa of certain leguminous seeds.

Abstract

SYNOPSIS.The structure of the hypodermal “pillar”‐cell layer of the testa has been examined in 15 leguminous species and, for each, the diagnostic characters of the testa, as seen in radial section, have been tabulated and figured.In the following species the “pillar” cells formed a single hypodermal layer: Lotus corniculatus, L. ornithopodioides, L. requienii, L. uliginosus, Dorycnium rectum, Ononis arvensis, Psoralea corylifolia, Ornithopus sativus, and Mucuna urens. No evidence of an intermediate layer of parenchymatous cells lying between the epidermis and the “pillar” cells has been found in these species.The “pillar” cells form a single hypodermal layer in Voandzeia subterranea and Lotus tetragonolobus.In Physostigma venenosum 1–3 layers of thick‐walled transition cells lie between the single layer of “pillar” cells and the inner layers of thin‐walled parenchyma. In Tamarindus indica a similar arrangement is found but there are many layers of transition cells which are either cubical or stellate in shape or are much compressed.Several layers of “pillar” cells form the hypodermal zone in the testa of Anagyris fœtida and of Copaifera salikounda, the cells of the true hypodermal layer being of somewhat greater radial length than are the remaining cells of this zone. In both species the cells below the hypodermal zone are thick‐walled and much compressed dorsiventrally.