26 British Uredinecs and Ustilannecs, 



follows that if all the spores in the field present this 

 central germ-pore, then of course there must be a corre- 

 sponding pore on the opposite side (Plate II. Figs. 4-7 

 and 10), so that when germination commences, the spores 

 assume a rouiTded cuboid form, with a germ-pore at each 

 angle. The process of germination continues from one 

 of these germ-pores, rarely from more than one. The 

 outgrowth of the endospore progresses, until it assumes 

 the form of a blunt-pointed, cylindrical tube. Into this 

 tube the protoplasm of the spore passes, and with it the 

 orange granules which give the colour to the spore. The 

 tube grows onwards for a considerable distance — ten or 

 more times the diameter of the spore. Contemporaneously 

 with the growth of the germ-tube, the protoplasmic con- 

 tents are continuously passed onwards to its extremity ; 

 so that the longer the germ-tube grows, the further are 

 the orange granules rem_oved from the spore in which 

 they were originally contained (Plate II. Figs. 6, 7, 10, and 

 14). The further development of the germ-tube consists in 

 its continued growth ; the walls, however, become not only 

 distinctly thinner, but give off various branches, mostly at 

 a right angle to the axis of its growth (Plate II. Fig. 7). 

 While these changes have been taking place, the whole 

 germ-tube has been making a series of convolutions, some- 

 times from right to left, sometimes from left to right 

 (Plate II. Fig. 6). Often a germ-tube will turn in one 

 direction during the first part of its course, and in the 

 opposite during the latter part. These circumnutatory 

 movements were observed by Tulasne * in ALc crassiim, 

 violcB, etc. This circumnutation of the germ-tubes I have 

 only observed in the Uredineae, and it is quite distinct from 

 the torsion one observes in other mycelial hyphae, when they 

 extend themselves into a dry atmosphere. This has been 



* Tulasne, " 2" Memoire," p. 12S. 



