ZOOLOGY AND BOTANY, MIOBOSCOPY, ETC. 269 



roots of beeches and on Monotropa growing beneath them, viz. : — 

 (1) Chalk-white, in which there is no true pigment, but the colour is 

 caused by a coating of minute crystals of calcium oxalate ; (2) pale pink, 

 both on the beech and on Monotropa ; (3) pale violet ; (4) orauge ; 

 (5) golden yellow ; (6) reddish brown. With regard to the degree of 

 connection of the parasitic fungus with the root, he distinguished 

 between ectotropic mycorhiza, in which the fungus clothes the root only 

 with an external coating, and endotropic, in which it attacks the cells of 

 the root itself. 



Of ectotropic mycorhiza far the most frequent is the ordinary coral- 

 like form. A second form occurs with long branches and root-hair-like 

 lateral organs. This has been observed on beech-roots, and completely 

 resembles externally ordinary roots not attacked by mycorhiza. The 

 external fungus-coating has here an extraordinary thickness, equal to 

 half the radius of the root itself, and consists of ordinary pseudo- 

 parenchymatous elements, the hyphas closely united together into 

 parallel bands. A third form of ectotropic mycorhiza occurs on the 

 roots of Pinus Pinaster from the Cape. The roots are covered with 

 patent hair-like filaments resembling coarse root-hairs. These are very 

 short and slender branches of the root so densely covered with mycorhiza 

 that the coating may even be as thick as the diameter of the root-branch. 



Of endotropic mycorhizas, one of the most remarkable forms is that 

 of the roots of Ericaceae (as well as Empetrum)* The roots infested by 

 it are distinguished by their very small diameter, from • 03 to • 07 mm., 

 their very simple internal structure, and the entire absence of root-hairs. 

 The epidermis forms the principal part of the root, and its cells are 

 filled with a colourless mass consisting of the mycorhiza-hypha?, which 

 constitute a pseudo-parenchymatous tissue somewhat of the nature of a 

 sclerotium, but distinguished by the extreme minuteness of its elements. 

 The root cap is, in these cases, reduced to a rudimentary condition. 

 The mycorhiza was not found on the roots of other heath and marsh- 

 plants growing in similar situations. 



Another form of endotropic mycorhiza is that of the roots and 

 rhizomes of Orchideaaf occurring in the interior of the cortical paren- 

 chymatous cells in the form of a ball of interwoven hypha), which pierce 

 through the walls of the cells. It occurs invariably in non-chlorophyllous 

 orchids, such as Neottia nidus-avis, Corallorhiza innata, and Epipogon 

 Gmelini, and is essential to the absorption by the roots of nutrient sub- 

 stances. The nature of the symbiosis is here one of mutual assistance ; 

 the protoplasmic body of the cell of the root and that of the fungus con- 

 tained in it carry on their existence side by side, without the former 

 being affected parasitically by the latter or its vital processes injured. 



Abnormal Fructification of Agaricus procerus.:):— Dr. E. von 

 Wettstein describes a specimen of this fungus in which three additional 

 pilei sprang on the underside of the primary one from between the 

 lamella?. All were fully developed. 



Sexuality of Ustilagineae.§ — Sig. F. Morini has made some obser- 

 vations on the question of the sexuality of Ustilagineae. In a previous 

 paper he had regarded the fusion of the conidia as an asexual copulation, 



* See this Journal, ante, p. 86. t See this Journal, 1886, p. 1029. 



+ Oesterr. Bot. Zeitscbr., xxxvii. (1887) pp. 414-5 (1 fig.). 

 § Mem. Accad. Sci. Bologna, vi. (1886) pp. 283-00. 

 1888. U 



