144 ASCOMYCETES. 



Chocolate-brown slime-flux. 1 



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

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

 Constant ini (Roll) is developed in large quantity. 2 



THE PARASITIC EXOASCEAE. 3 



In this family are included the genera Exoascus, MagnusieV, 

 and T<iphrin. The asci of most of the known species are 

 produced from a mycelium which lives under the cuticle of the 

 host-leaf, in a few (e.g. Magnusidht /ra), the mycelial 

 hyphae are developed between the cells of the epidermis, 

 while in others (e.g. M. potentillac), the mycelium permeates 

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

 under the epidermis. T. Laurencia 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. Waldbaume," Forst.-naturuiss. Zeitschrift, 

 1893, and 1894. 



2 Kriiger has found various micro-organisms, including a fungus (Prototheca) 

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

 Physiol. n. Morph. nied. Orr/anitmen, 1894.) 



3 Sadebeck : (1) Untersuch. ub. die. Pilzr/attunr/ Esoascus, 1884. (2) Kritische 

 Untersuch. i'di. die diirck Taphrina- Art en hervorgebrachten Baumkrankheiten, 

 1890. (3) Die parasitixchen Exoasceen, 1893. (4) " Einige neue Beobachtungen u. 

 kritische Beinerkungen lib. die. Exoasceae," Ber. d. deutsch. botan. Ges., 1895. 



Johanson : (1) Studier offer timmpsiayet Taphrina, 1887. (2) Om tfcawz^- 

 Kfi'ii/ft-t, Taphrina och ditliijrande Svenska arter, 1885.; 



Rostrup, Taphrinaceae Daniae, 1890. 



DC Bary, B<-ilni<,,- -.. Morph. n. Physiol. d. Pilze, 1864-1870. 



Giesenhagen, " Die Entwickeluugsreihen der parasitischen Exoasceen. " Flora, 

 Erganzungsband, IS!).'). With numerous figures from microscopic sections. 



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

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

 Station, Bu'lethi 73, 1894. With numerous illustrations. 



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

 LaJi. '>i<(/. Itixf., i'liir. of I<ra, 1895. 



Smith, " Untersuch. der Morjili. u. Anatomie der durch Exoasceen verursachten 

 I ) fi/i'inalioiK 1 ]!." l'\>r*t.-nttt iirir'ixx. Z, !/.--r/i rift, Munich, 1894; Italian, translation 

 ly ilerlese, l!'u-i.<t<i di Patologia, 1895. 



