4 British UredinecB and UstilaginecE. 



CHAPTER II. 



MYCELIUM OF THE UREDINE/1\ 



This is, of course, common to all the different spore- 

 forms, inasmuch as it is that part of the fungus which 

 develops them. It consists of a number of hyaline tubes 

 that extend themselves principally between the cells of 

 the host-plant. In some instances these tubes send short 

 branches into the cells (haustoria), but the haustoria are 

 not so common nor so well developed as in some other 

 parasitic fungi (Peronosporeae, Ustilagineae). In the 

 tropical genus Hemileia * the haustoria are unbranched, 

 thin-stemmed vesicles, very like those of Cystopus. Bagn is t 

 has figured the haustoria of Pucciiiia malvacearnm, but his 

 figure is of a doubtful character ; and Barclay^ has depicted 

 an arborescent haustorium on the mycelium of j^cidiuni 

 iirtic£B, var. hinialayense. 



The mycelial tubes (Plate I. Figs, i and 2) consist of 

 hyaline, membranous walls, containing usually a colourless 

 watery fluid. They are rendered more distinct by the 



* Marshall Ward, "On Hemileia vastatrix," Linn. Soc. Jour. Bot., vol. 

 xix., and Quart. Joiir. Micr. Science, new series, vol. xxi. 



t Bagnis, " Obs. Vita et Morphol. Funghi Uredinei," t. i. fig. ii. 



X Barclay, "Scientific Memoirs by Medical Officers of the Indian Army" 

 (1S87), t. iv. fig. 4. 



