144 ASCOMYCETES. 



Chocolate-brown slime-flux.' 



A slime-tlux of this colour appears on the stumps, of felled 

 beeches ; it contains numerous forms of Oidium, and later Ascoholns 

 Constantini (Roll) is developed in large quantity.^ 



THE PARASITIC EXOASCEAE.^ 



In this family are included the genera Exoascus, MagnvsicUa, 

 and Taphrina. The asci of most of the known species are 

 produced from a mycelium which lives under the cuticle of the 

 liost-leaf, in a few {e.g. Magnusiella fiava), the mycelial 

 liyphae are developed between the cells of the epidermis, 

 while in others {e.g. M. potentillae), the mycelium permeates 

 the whole leaf-tissue and the asci arise from hyphae situated 

 under the epidermis. T. Ltturencia and a few others have an 

 intracellular mycelium, and produce asci inside the epidermal 

 cells. A number of species are known to possess a perennating 

 mycelium, in the remainder the hyphae are wholly used up in 

 the formation of asci. 



The ascospores produce conidia before leaving the asci, which 

 are therefore frequently found filled with minute conidia instead 

 of the usual ascospores. In nutritive solutions the conidia sprout 

 yeast-like ; on a host-plant, they give rise to a hypha which 

 penetrates the cuticle. 



^Ludwig, " Ein neuer Pilzfluss d. ^^'aldbaume," Forst.-naturu'isn. Zeit'ichrift, 

 1893, and 1894. 



-Kriiger has found various niicro-organisnis, inchiding a fungus {Prototheca) 

 and several algae, in the slime-flux of broad-leaved trees. (Zopf, Beitr. z. 

 Physiol, u. Morph. iiied. Organinmen, 1894.) 



=*Sadebeck: (1) Untersuch. iib. die Pikfjattmifj Ejoascus, 1884. (2) Kritische 

 Untersuch. iib. die durch Taphrina-Arttii herror<jehrachten liainiil-rdiil-liiiten, 

 1890. (.S) Die parasitisclmi Exoasceen, 1893. (4) " Einige neue T.cdlia.lidin-en u. 

 kritische liemerkuugcn ul). die. Exoasceae," Ber. d. deutsch. holaii. OV.s. , 1895. 



Johanson : (1) S/ndiif iij'n r Srnmpslaget Taphrina, 1887. {-) Otn Sramp- 

 .tliititet Taphrina och (liih<ir<i udi Sn nska arter, 1885.] 



Rostrup, TaphriiKtiui, hanidi, 1S90. 



l)e Baiy, BeitrCuje z. Morph. u. Physiol, d. Pilze, 1864-1870. 



(Jiesenhagen, " Die Entwickelungsreihen der parasitischen Exoasceen." Flora, 

 Erijd7izuii<jsiiand, 1895. With numerous flgiu-es from microscopic sections. 



Atkinson, " Leaf-curl and plum-pockets." A contribution to the knowledge of 

 the prunicolous Exoasceae of the United States. Cornell Univ. Jgric. Exp. 

 Station, BuHetin 73, 1894. \Vith numerous illustrations. 



Patterson, "A study of N. America parasitic Exoasceae." Bulletin of the 

 Lab. nat. hint., Univ. of loica, 1895. 



Smith, "Untersuch. der Morph. u. Anatomie der durch Exoasceen verursach ten 

 Dcformationen." Forst.-naturwiss. Zeitschrift, Munich, 1894 ; Italian, translation 

 by Berlese, Bivista di Palologia, 1895. 



