Schwarze: Cleavage in Sporangia 



171 



60. Zopf, W. Zur Kenntniss der Phyco.myceten. 1, Zur Morphologie und 

 Biologie der Ancylisteen und Chytridiaceen. Nova Acta K. Leop. Carol, 

 deutsch. Akad. der Naturf. 47: 143-236. 1884. 



Explanation of Plates 



All figures were drawn with the aid of the camera lucida, and with the 

 Zeiss 1.8 mm. objective, N. A. 1.25 ; magnification about 1300 diameters. 



Plate 15 

 Sporodinia grandis 



Fig. 1. Median vertical section of a sporangium showing cleavage com- 

 plete on one side and first appearance of superficial cleavage furrows. 



Fig. 2. Median vertical section of a sporangium showing columella-cleft 

 completely formed and furrows passing upward through the spore plasm. 



Fig. 3. Tangential section of a sporangium showing an advanced stage of 

 cleavage and a large central mucorin crystal. 



Fig. 4. Oblique section of a sporangium, spores have become polygonal by 

 mutual pressure (expansion phase). 



Fig. 5. Tangential section of a sporangium representing an early stage of 

 cleavage. 



Fig. 6. Median vertical section of a sporangium, columella-cleft and 

 cleavage complete on one side of the sporangium and in an advanced stage on 

 the other side. 



Plate 16 



Fig, 7. Sporodinia grandis. Tangential section of a sporangium showing 

 advanced stage of cleavage. 



C ire in ell a minor 



Fig. 8. Tangential section of a sporangium showing branching furrows. 



Fig. 9. Horizontal section of a sporangium ; spore plasm cut into oblong 

 to sausage-shaped protoplasmic masses which are somewhat concentrically ar- 

 ranged and are undergoing transverse segmentation. 



Fig. 10. Section of a portion of a sporangium, protoplasmic masses are 

 being cut up into 1-2 nucleated protospores. 



Fig. 11. Vertical median section of a sporangium, somewhat later stage 

 of cleavage than shown in figure 10. 



Fig. 12. Oblique section of a sporangium about same stage as the last. 



Fig. 13. Spores have become multinucleated and polygonal (expansion 

 phase). 



Fig. 14. Mature multinucleated spores. 



Mucor racemosus 



Fig. 15. Tangential section of a sporangium showing the beginning A 

 two cleavage-furrows. 



Fig. 16. Tangential section of a somewhat larger sporangium, the pro- 

 toplasm is being cut up into irregular blocks. 



