■74 



DIVISION II. — COURSE OF DEVELOPMENT OF FUNGI. 



of the ovule remains undifferentiated, and an abundant formation of new hyphae is 

 constantly taking place in it. This new formation is so added from below to the 

 differentiated portion, that the latter constantly increases in height without becoming 

 materially broader, and maintains therefore the form of a cylinder pointed at the upper 

 end. Where the parts below approach the wall, columella, and spore-mass, they assume 

 their structure and colour. In other words, each of the three portions grows from its 

 base by addition of new tissue-elements, which are constantly being produced and 

 pushed onwards from a basal formative tissue, and are differentiated and assume their 

 ultimate form in the order in which they arc produced (Fig. 80 C and D). The 

 development and mature structure of the spore-mass are the same as those of Ustilago, 



which will be described presently. The 

 wall in its fully developed state is a thick 

 coat formed of many irregular layers of 

 small round cells not very firmly united 

 together. These cells are formed in the 

 same way as the spores from the hyphae 

 of the primary tissue, and are of about the 

 same size as the spores with a delicate 

 colourless membrane, and for the most 

 part with watery hyaline contents. The 

 columella has the structure of the wall, 

 but it usually incloses in its tissue evident 

 brownish fragments of the tissue of the 

 ovule, and consists at its uppermost ex- 

 tremity of much larger, firmer hyaline 

 cells, the origin of which I am unable 

 to explain. I may also observe that the 

 upper extremity in young specimens always 

 ends blindly in the spore-mass (C), but 

 in some older ones reaches to the apical 

 portion of the wall and passes into it (D) ; 

 it is still uncertain whether this is a dif- 

 ference in the individual plants or a 

 difference of age. 



The spore-receptacle which has now 

 been described is formed only from the 

 ovule. The perianth and stamens of the 

 flower continue in their normal state. 

 The wall of the ovary and the style are 

 also not attacked by the Fungus ; they 

 do not follow the growth of the spore- 

 receptacle, and as this advances the 

 lateral wall is distended and at length 

 bursts transversely ; the style with the 

 upper portion of the wall dries up into a 

 small point at the apex of the receptacle, which is borne by the latter as it grows out of 

 the perianth (A). The wall of the spore-receptacle, especially where it is covered above 

 by the withered remains of the wall of the ovary, is very fragile and tears asunder at 

 the slightest touch to discharge the spores (B). 



Section LV. The development of the resting- spores commences in Entyloma 



. 81 a), as in Protomyces, with intercalary abjunction at any spot in the hyphae; 



in Tilletia the resting-spores are terminal, being formed singly from the extremities of 



blanches of sporogenous hyphae. In Geminella Delastrina they originate by serial 



FIG. 80. Spacclothcca Hydropipcrismxheftov/er of Polygonum 

 Hydropiper. A ripe compound sporophore of the Fungus pro- 

 jecting from the i>erianth of Polygonum. R the same with the 

 mass of spores emerging from the sporophore. C median longi- 

 tudinal section through a young fructification and its environ- 

 ment. D longitudinal section through an older sporophore. c" the 

 columella, p the perianth, y the wall of the ovary, o the integument 

 1  of the ovule, g the style. In C and D the 



1 the Fungus is shaded by longitudinal lines, the 

 1 ition In the 



text. Slightly magi 



