FUNGI. CHYTRIDIEAE. 85 



1. CHYTRIDIEAE. 



The Chytridieae 1 are Fungi of the most simple organisation. There is an 

 advance within this group from unicellular forms without a mycelium to others which 

 possess a mycelium. Reproduction is effected by means of swarm-spores, which 

 usually have but one cilium. Resting cells are also found in many species, \\hich 

 germinate and become sporangia producing swarm-spores. A sexual process has 

 been described only in the case of Polyphagus Euglenac, in which according to 

 Nowakowski a zygospore is formed 2 . 



Chytridium has no mycelium, but consists of single cells which live on or within the 

 plant that feeds them. The cells after reaching their full size become zoosporangia. 

 The swarm-spores have only one cilium, which is in front or at the hinder end in the 

 peculiar backward hopping movement which they exhibit. The plants live on living or 

 dead organisms in water and are parasitic on other Fungi and on Algae. The genus 

 Rhizidiurn has the rudiment of a mycelium in the form of slender branched root-like 

 processes on the cell which produces the swarm-spores, and from which the mycelium 

 is separated by a transverse wall. Cladoehytrium, on the other hand, has a distinct 

 delicate filiform mycelium which proceeds from cells that produce zoospores, and bears 

 new zoosporangia. The Cladochytrieae are parasites on water or marsh Phanerogams, 

 for instance on MenyantJies. 



The genus Protomyces 3 comes near to the Chytridieae. The mycelium of 

 Protomyces inacrosporus, composed of segmented filaments, is parasitic on the stems 

 and leaf-stalks of Aegopodium Podagraria and other Umbelliferae, and causes peculiar 

 marks on them like weals. Single cells of the mycelium swell into tough-walled resting 

 spores, which germinate in the spring following their formation. An inner membrane 

 protrudes from the outer, and its contents form a number of small cylindrical rod-like 

 bodies, spores, which however have no cilia. These are set free and conjugate in pairs, 

 forming by their union an H -shaped body. A germ-tube grows out from one of the two 

 united spores, and forces its way into a healthy plant of Aegopodhun, and there 

 produces a mycelium which again generates resting-spores. No gonidia have been 

 observed. 



2. USTILAGINEAE. 



The Ustilagineae 4 are parasites which live inside land-plants, some in their 

 intercellular spaces only (Entyloma), while some penetrate the walls of the cells of the 



' A. Braun, Ueber Chytridium, eine Gattung einzelliger Schmarotzergewachse (Abhandl. d. Berl. 

 Akad. 1856). Nowakowski, Beitr. z. Kennt. d. Ch) tridiaceen, I, II, in Cohn, Beitr. zur. Biol. d. 

 Pflanz., Bd. II. [In De Bary, Vergl. Morph. u. Biol. d. Pilze, Mycetoz. u. Bact., Leipzig 1884, p. 184, 

 the literature up to 1884 will be found.] 



2 [Now known in other forms ; see de Bary ; also Fisch, C., Beitr. z. Kenntn. d. Chytridiaceen, 

 Enlangen, 1884; Borzi, Nowakowskia (Bot. Centralbl. XXII (1885).] 



3 De Bary, Beitr. z. Morph. u. Phys. d. Pilze, I Reihe (Abhandl. d. Senckenberg'schen Ges. zu. 

 Frankf. a. M., V. Bd. 1864 ; [see also Vergl. Morph. u. Biol. d. Pilze, Mycetozoen u. Bacterien, Leipzig 

 1884, p. 199, for the literature]. 



4 The position of the Ustilagineae is still unsettled even after the latest investigations, but at 

 present it seems most natural to connect them with the Chytridieae. See Tulasne, Mem. sur les 

 Ustilaginees comparees aux Uredinees (Ann. d. sc. nat. 3 ser. t. VII), and 2d e Mem. sur les Ured. et 

 les Ustilag. (Ann. d. sc. nat. 4 ser. t. II). De Bary, Unters. ii. d. Brandpilze, Berlin 1853; Id. 

 Protomyces microsporus (Bot. Ztg. 1874, p. Si); [also De Bary, Vergl. Morph. u. Biol. d. 1'il/c, 

 Mycetozoen u. Bacterien, Leipzig, 1884, p. 200, where further literature is quoted.] Wolff, Beitr. 

 z. Kenntniss d. Ustilag. (Bot. Ztg. 1873). Woronin, Unters. ii. d. Ustilag in De Bary u. Woronin, 

 Beitr. z. Morph. u. Phys. d. Pilze, V. Reihe, 1882 (Abh. d. Senck. Ges. zu Frankfurt a. M.). [Weber, 

 Ueber den Pilz der Wurzelanschwellungen v. Juneus biibrmis (Bot. Zeit. 1884).] 



