TAPHRINALES 



163 



The position and germination of the chlamydospores in the leaves of 

 the host vary. In T. epiphylla on Alnus incana, (Juel 1921), T. bullata 

 and T. Betulae (Exoascus Betulae) on Betula alba (Eftimiu 1927), the 

 mycelium grows subcuticularly on the leaves and consequently the 

 chlamydospores are formed between the epidermis and cuticle. In T. 

 aurea on poplar, T. Alni-incanae and T. Crataegi, the mycelium appears 

 just below the epidermis. In the majority of the Taphrinales, as in T. 

 deformans, T. institiae and T. Pruni, the vegetative mycelium grows in 

 the parenchyma while the ascogenous mycelium which forms the chlamy- 

 dospores develops only under the cuticle. In T. (Magnusiella) Potentillae 



O^ooSH aads 



Fig. 101. — Taphrina deformans. 1. Hymenium (X670). Taphrina Carpini. 2. 

 Germination of asci in distilled water (X400). Taphrina aurea. 3, 4. Hymenium 

 (X 330). (After Gwynne-Vaughan, 1922, and Sadebeck, 1884.) 



on Potentilla, the mycelium lives only in the interior of the leaves and 

 the asci, as in Taphridium of the Protomycetaceae, are formed in a 

 mycelial layer under the epidermis. In T. aurea on Populus and T. 

 epiphylla on Alnus, the whole outer wall of the chlamydospores continues 

 in the wall of the young ascus. There is no septum between ascus 

 and chlamydospore, i.e., no abjunction of a stipe cell (Fig. 101, 3 and 

 4; 102, 4). The types of germination of these forms are occasionally 

 strikingly reminiscent of the Protomycetaceae. In T. Coryli on Conjlus 

 americana, the diploid nucleus divides into two daughter nuclei in the 

 chlamydospore. One remains in the basal cell and degenerates; the 

 other migrates into the young ascus and divides there into the 8 spore 

 nuclei (Martin, 1924). 



