8 H. MAllSHALL WARD. 



the exospore remains smooth and thin for some time. As the 

 regular ovoid shape of the spore becomes altered by lateral and 

 other pressures the thickening exospore develops the solid 

 papilla?, above, and the contents begin to assume the orange-red 

 tinge. 



As the spore-bearing branches (each of which forms spores as 

 above at first) pass through the orifice of the stoma they are 

 crowded together into a neck ; below and above this constriction 

 they expand again. As age advances, however, they are found 

 to become coalesced into a kind of pseudo-parenchyma, and the 

 later-formed spores arise from the sides and top of a compound 

 body (figs. 39 and 40 d), produced by their union. This struc- 

 ture presents the form of an oval boss, with its lower side 

 attached by a neck, which passes through the stoma to the 

 mycelium within the leaf; its sloping sides are covered with 

 crowds of short, stumpy processes (fig. 41), the remains of 

 pedicels from which spores have fallen. The fusion of mycelial 

 elements may even extend to the internal position close to the 

 neck, and possibly the " dark body" figured by Abbay^ 

 is this structure, into which air had penetrated. 



Yiewed from above, the various stages of spore formation are 

 easily discovered. The story is the same. A few ovoid young 

 spores arise (fig. 41 a, b), and additional ones bud off from near 

 their bases {c), until a rosette-like cluster is formed [e). The 

 appearance of the old spore-bearing head, formed by the fusion 

 of the spore-bearing branches, is figured at fig. 41 y. When 

 the " disease spot" has ceased to spread, and all, or nearly all, 

 the spore-bearing heads have become as advanced as this, the 

 second form of spore is produced. 



This Teleutospore is a very remarkable body, and it is only 

 intended here to describe its morphological characteristics. It 

 is at first indistinguishable from the young Vredospore, but, 

 instead of developing into the reniform papillate structure, it 

 remains somewhat smaller, quite smooth, and expands into 

 a subglobular shape. When fully formed it is napiform, 

 and situated on a short stalk (fig. 44) attached to the spore- 

 bearing head already described (figs. 38 and 39). An endo- 

 spore is early distinguishable, and the granular protoplasmic 

 contents soon become coloured bright orange red. 



Very soon after its complete formation the central portion of 

 the free, slightly flattened end of the oblate spheroid protrudes 

 as a rounded, blunt, boss-like eminence ; this goes on until the 

 whole structure assumes the shape of a flask (fig. 39). This 

 outgrowth of the apex is the first indication of germination, and 

 the free, straight, neck-like portion is the promycelium. The 

 1 Loc. cit., p. 177, Plate 13, fig. 4, &c. ' 



