﻿4M BOTANICAL GAZETTE ' [jUNE 



fungus are described. The Chytridiales have offered an open field 

 for speculation heretofore, and have baffled definite judgment as^ 

 to their nature and relationship. Fuller knowledge of their 

 cytological peculiarities may lead to a more satisfactory con- 

 dition. 



North Carolina 



College of Agriculture and Mechanic Arts, 



Raleigh. 



EXPLANATION OF PLATES XVI AND XVII. 



All figures are from material killed in chrom-acetic acid and' stained 

 with Flemming's triple stain. The figures were sketched with an Abb6 

 camera, using a Leitz ,^2"» 3-P- i*30i giving an enlargement of 1790 diameters, 

 with the exceptions oifigs. i and ^, which were drawn from a Bausch and 

 Lomb I, with a magnification of 750 diameters. Plate not reduced in repro- 

 duction. 



PLATE xvr. 



Fig. I. One parasitized cell in early stage of development, showing large 

 nucleus and nucleolus surrounded by granular cytoplasm ; adjacent cells 

 show nuclei and chloroplasts. 



Fig. 2. Parasite nearly at end of growing period; nucleus heavy walled, 

 vacuolate ; chromatin distributed along nuclear wall, around the nucleolus, 

 and on connecting strands. 



Fig. 3. Single nucleus of a stage similar to but slightly later thany?^. 2, 

 and more highly magnified ; nuclear vacuoles prominent, nucleolar substance 

 giving way to vacuoles; chromatin on nuclear wall also arranged in irregular 

 heaps around the nucleus ; nuclear wall still definite and firm. 



Fig. 4. Portion of nucleus slightly later, showing the continued wasting 

 of the nucleolus and a somewhat more even distribution of chromatin. 



Fig. 5, Portions of nucleus still later; nucleolus not present; the large 

 chromatin lumps and globules oifig. 4 have given place to more numerous 

 and smaller ones which have also taken on a much more even distribution, 

 thus largely obliterating the large conspicuous vacuole of earlier stages; the 

 nuclear membrane is less distinct on its outer border. 



PLATE XVII. 



Fig. 6. The chromatin globules of earlier figures are assuming the rod- 

 form ; the nuclear membrane has softened from the outside inward, being 

 now largely represented by a thick layer which stains darkly with the 

 orange G. 



Fig. 7. Chromatin rods entirely replace the globules of earlier stages; 

 these rods intersect at sharp angles, often appearing as dots from end view; 

 a nucleolus, similar in stain to the nucleolar vacuoles mfig. 4, is seen to the 



