1886.] "Himalayan Spruce-fir (Abies sraithiana). 7 



immersion in alcohol. In many places, the mycelial filaments may be 

 seen in parallel lines closely applied to the external surfaces of the 

 parenchyma cells. The main mass of the mycelium, therefore, lies in 

 the parenchymatous tissue, that is, between the hypodermal cells and the 

 endodermic sheath surrounding the central wood bundle. A few filaments 

 may be seen insinuated between the hypodermal cells and reaching the 

 epidermis cells. The extension of the mycelium inwards is largely and 

 conspicuously arrested at the endodermic sheath. Some filaments do, 

 however, pass between the cells of this sheath and may be traced among 

 the parenchyma cells. A very few may be traced in the phloem, but 

 none in the xylem. A special aggregation of filaments occurs between 

 the phloem and the cells of the sheath, entirely replacing the central 

 sclerenchyma cells. 



The minute structure of the mycelial filaments does not present 

 any special characteristics (fig. 9) : they are septate and branched. 

 While coursing through the parenchyma, they are not specially con- 

 voluted, but become very much so at the bases of the secidia and sperma- 

 gonia. A few haustoria occur in the cells of the parenchyma : they are 

 of the branched type and by no means numerous : as the mycelial 

 filaments are so closely applied to the cell walls, appearing as if cemented 

 to them, there would appear to be little necessity for haustoria. 



My specimens were unfortunately not favourable for the investiga- 

 tion of the course of the mycelium in the stem. The mycelial filaments 

 were, however, seen to ramify abundantly both in the cortical tissue and 

 also among the pith cells. The circle of vascular tissue was frequently 

 found to be broken in outline in order to allow of strands of the fila- 

 ments entering. I was unable to detect any actually between the wood 

 cells. The filaments here presented the same characters as those de- 

 scribed above. 



Spermagonia. — These, as already stated, occur in great numbers ; 

 they are deeply set with their bases beneath the hypoderma, and 

 measure about 0'139 m. m. in length and breadth. The conical neck 

 protrudes 45/x above the level of epidermis (fig. 12). They are of the 

 usual structure and require no description. The mycelium at their 

 bases forms densely convoluted masses which thrust the epidermis and 

 hypodermal cells widely apart. The spermatia are very minute oval 

 bodies (fig. 10). 



^cidiospores. — By reflected light the secidiospores are pale yellow. 

 They are long irregularly oval bodies densely beset externally with 

 minute spines or tubercles. Many of them are rounder at one extremity 

 than at the other and some are flattened and curved (fig. 7). The 

 dimensions of the dry spores were on an average 38/u by 16/>t. These 



