. Morphology of spermatophytes. [Part I. Gymnosperms]. Gymnosperms; Plant morphology. 9Q MORPHOLOGY OP SPEEMATOPHYTES seems to have been the first to see all the four structures in the pollen tube injected into the egg, an observation which has been frequently confirmed since. It should be remembered, however, that in the case of Taxus haccata Belajeff ^° reports the passing into the egg of a single male cell only, the smaller one re- maining in the tube. In Pinus, in Taxodium as shown by Coker,*^ and in 0ephalotaxus as shown by Arnoldi,*^ the upper part of the cytoplasm of the egg, after the
. Morphology of spermatophytes. [Part I. Gymnosperms]. Gymnosperms; Plant morphology. 9Q MORPHOLOGY OP SPEEMATOPHYTES seems to have been the first to see all the four structures in the pollen tube injected into the egg, an observation which has been frequently confirmed since. It should be remembered, however, that in the case of Taxus haccata Belajeff ^° reports the passing into the egg of a single male cell only, the smaller one re- maining in the tube. In Pinus, in Taxodium as shown by Coker,*^ and in 0ephalotaxus as shown by Arnoldi,*^ the upper part of the cytoplasm of the egg, after the discharge of the tube, con- tains two male cells, the disorgan- izing tube nucleus and stalk cell nu- cleus, besides cytoplasm of the tube and starch grains. The cytoplasm of the male cells is no longer distinguish- able, and their nuclei may be recog- nized by their large size and more deeply staining contents as compared with the tube and stalk cell nuclei, which can hardly be distinguished from each other. One male nucleus moves forward through the cytoplasm of the egg, the other three injected bodies re- maining near the top of the egg and gradually disappearing. Arnold! *^ makes an interesting observation in connection with the func- tionless male cell in Cephalotaxus Fortunei. He reports that as it lies unused in the peripheral region of the cytoplasm of the egg it may divide amitotically, one of his figures showing six nuclei as having been derived from a single functionless male nucleus. According to Blackman,*'^ the functional male nu- cleus moves very rapidly and increases in size, an increase appar- ently due in some cases to actual increase of stainable substance, and in others to vacuolation. The male nucleus of Pinus is nearly spherical, with a diameter of about 40/i, and is usually one third (rarely one half) the diameter of the ellipsoidal or egg- shaped nucleus of the egg. The behavior of the male nucleus after it reaches the egg nu- cleus is peculiar (Fig. 74
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