MorpJwlogy. 2 7 



reproduction. In tlie Ustilaginece and tlie Uredlnece, 

 illustrated by '^ rust/' ^' bunt/"* and " mildew '' on 

 corn, the last vestiges of tlie sexual form of repro- 

 duction disappear, the gonidial condition alone remain- 

 ing, and in the Basidiomycetes the gonidiophores or 

 hyph83 directly bearing the gonidia have assumed 

 characteristic and permanent forms, henceforth known 

 as basidia, and the reproductive bodies to which they 

 give origin are called spores. In the Protohasidiomy' 

 cetes the basidia are septate ; in the genus Pilacre 

 the basidium is formed from the cylindrical, swollen 

 tip of a hypha which is divided into four equal cells 

 by three transverse septa, each cell giving origin to a 

 single spore. In Tremella the basidia appear as the 

 swollen tips of hypha?, which, soon become divided at 

 the apex by two vertical septa crossing each other at 

 right angles, each of the four apical portions elongates 

 into a long, slender, tapering tube, continuous with 

 the cavity of the swollen basal portion or basidium, 

 known as a sterigma. Each sterigma finally becomes 

 swollen at the apex, into these swellings the whole of the 

 protoplasm contained in the basidium and sterigmata 

 becomes concentrated, the swollen tips are then 

 separated from the cavity of the sterigmata by the 

 formation of the transverse septa, and drop off as 

 mature spores. In the AtitohaMiomy cetes the basi- 

 dium is met with in its most highly differentiated 

 condition, and consists at first of a large, terminal, 

 clavate cell, producing at the apex four slender, spine- 

 like sterigmata, each carrying a spore at its apex. In 

 Dacryomyces and allied genera only two sterigmata 

 are present on a basidium. In all cases basidia are 



