42 



BOTANICAL GAZETTE [july 



divide amitotically. No actual case of such amitosis, however, has 

 been observed in any stage of the tapetum. No mitotic figures have 

 been observed in the plasmodium either, though the nuclei seem 

 somewhat more abundant in the later stages. The sporangia vary 

 so much in size and consequently in number of nuclei found at any 

 stage that it is not possible to say with confidence that the nuclei 

 increase after the walls of the tapetum have disappeared. That the 

 nuclei do not move about passively in currents of cytoplasm seems 

 to be indicated by the fact that where one is apparently just entering 

 a crevice it is always drawn out to a point, which stains more deeply 



F 



with chromatin stains than do the other parts of the nucleus. Beer 

 has called attention to similar appearances of the nuclei of Helmin- 

 thostachys. The average size of the nuclei does not differ materially 

 in older stages from that of the earlier ones. There is considerable 

 individual variation of both size and shape at any stage. Cardiff 

 has pointed out that the nuclei of the plasmodium of Botrychium 

 increase fourfold in size; but Beer has found that this is not the case 

 in Helminthostachys. The structure of the nucleus, however, does 

 undergo considerable change. A reference to fig. i6 shows the 

 tendency of the chromatic material in the later phases of development 

 to aggregate itself into elongated masses, whose long axes are directed 

 lengthwise of the nuclei. These masses are much fewer than the 

 chromosomes. A similar condition is shown in Beer's "figures of 

 Helminthostachys. When the nuclear membrane breaks down, these 

 masses are spilled out and persist for some time. The nuclei persist 

 longer than the cytoplasm; it is not uncommon to find one or more 

 of them in sporangia from which the spores are just about ready to be 



shed. 



THE SPOROGENOUS TISSUE 



The earliest stage of the sporogenous tissue observed is shown in 

 fig. 8. At this time it probably lacks about two divisions of the 

 mother-cell stage. The cells are squarish or polygonal, and about 

 25 /i- in diameter. The nuclei, which var}^ slightly, average about 

 18 /A in diameter. The cytoplasm is delicately reticulated and does 

 not stain very intensely. It seems to be made up of a network of 

 delicately beaded strands, the meshes of which are filled with a 

 hyaline ground-substance w^hich stains very lightly or not at all. The 



