242 



COMPARATIVE MORPHOLOGY OF FUNGI 



forms lumps 2 to 3 cm. in diameter, in whose periphery are embedded 

 the perithecia (Hennings, 1901). 



The second group of the Hypocreales, that of the Didymosporae- 

 Phragmosporae-Dictyosporae, shows morphologically the same funda- 

 mental characters as the first group, the Amerosporae. It begins with 

 simple forms without stromata and develops gradually to a continually 

 more differentiated stromatic type which reaches a height of development 

 in each of three spore series corresponding to that of the lower Polyporales 

 of the Basidiomycetes. While these four series in the table on page 233 

 follow rather identical lines in the differentiation of their stroma and 

 hence end with fructifications externally alike, in the third group of the 



Hypocreales, that of the Scolecosporae, we will 

 have to follow at least three divergent directions 

 of development: the first, represented by the 

 Oomyces-Ascopolyporus series, which reaches the 

 height of the Polyporales in the formation and 

 structure of a perithecial hymenium; a second 

 represented by the Epichloe-Claviceps series 

 which, by physiological differentiation of its stro- 

 mata, has arrived at types peculiar to the Hypo- 

 creales; and a third, represented by the Cordyceps 

 group, which is a copy of Hypocrea and its rela- 

 tives in the Didymosporae. 



The Oomyces-Ascopolyporus series, through 

 Oomyces, is connected directly to the level of 

 the stromatic Nectriaceae. Oomyces forms flat- 

 tened, slightly differentiated mats in which are 

 (Natural size; after Mailer, embedded the per ithecia. In Brazil Oomyces 



monocarpus develops on Merostachys speciosa, a 

 bamboo, small, soft, light yellow to reddish stromata, 1 to 2 mm. 

 high, each of which contains a single perithecium. Occasionally several 

 stromata may be confluent at the base or may come together into small 

 mats. The structure of the perithecial wall is markedly different from 

 the structure of the stroma. Still more marked is this differentiation in 

 the Javan Oomyces javanicus, forming its stromata on the undersides 

 of the leaves of Vaccinium varingifolium. Here the differentiation 

 between perithecium and stroma has gone so far that pressure on the 

 cover glass easily forces the perithecium out of the stroma. 



In Konradia and Hijpocrella, the stromata begin, as in the Sphae- 

 rostilbe-Megalonectria group of the Didymosporae-Dictyosporae, to 

 individualize and develop to fructifications of definite form. On bamboo 

 twigs in Java, Konradia bambusina forms irregular lumps, on whose upper 

 surface are imbedded the perithecia. While the outer parts with the 

 older perithecia die, become carbonaceous and crumble, intercalary 



Fig. 157. — Mycocitrus au- 

 rantium. Perithecial stroma. 



