Physiological Importance of Calcium in Legume Inoculation

Abstract

1. The origin of the large solitary sporangium is marginal. 2. The sporangium wall and tapetum arise from segments cut from a dolabrate apical cell. 3. The primary sporogenous cell by three successive divisions gives rise to sixteen spore mother cells. 4. Subsequent to the formation of the spore mother cells and the tapetal plasmodium there is rapid increase in the sporogenous mass. 5. A striking feature is the formation of multinucleate spore mother cells, which is not uncommon. 6. Two features render additional support to the relationship of Schizaeaceae to Marsileaceae proposed by Campbell and supported by Bower: (a) The spore output of S. rupestris has advanced to 64 per sporangium as compared with the prevailing number of 128 in most species. This reduction in spore output has reached the upper limit of Pilularia (64-32). (b) Multinucleate spore mother cells resulting from a failure of wall formation following nuclear division is a step toward the heterosporous condition of the Marsileaceae.