8 



iHtnrisliiiK'iir. Tliosc liimstorin jncsoiit sovornl foiiiin, mid tlicy me ol' 

 8(mic iinportiincc in the cliissiliriUioii of the spw-ios. In some (.'iiscrt tlio 

 Iiiuistoi'imn siniiily • )nxists nfii siciulcr tiilx^ wliicli pciictrafcs tlic cpi- 

 (icrinal cell of tlu! host, \, itliiii which it swells to an oval <»r clult-shiiiit'd 

 sac. lilletl with <;riimilar pi-otoplasni. More often there is an externa! 

 ai»iien(la,i:e or suekei', that ia jtressod close to the surface of the e]»ider- 

 nial cell, and from this, or from near it on the mycelial thread, the 

 iiaiistorinm proper takes its rise anti penetrates tlie e])idei'mis. This 

 external appendaue may Ite smooth and entire, merely constituting a 

 hemisphei'ieal swellin.sr on the mycelial thread, or, it uiay take the 

 form of a Ihittencid disk with an indented marjiin. In the latter case 

 It is said to l»e " lohed," in the former, "not lol)ed." 



The conidia, or asexual rejtroductive liodies, are cylindrical, oval 

 or nearly orhicular, sim])le, colorless cells fdled with protoplasm. 

 They are I'ormed l>y constriction at the ends ol" sliort, simple, erect, 

 rather stout, sejjtate, colorless hranches of the niycolium, called fertile 

 liyi)ha; or coindio})hores. A sei»tum forms near the end of the young 

 hypha, and the walls at this point become constricted. The ccl' thus 

 cut olf usually swells a little, and at length Aalls away as a matuie 

 conidium. JJcfore this ha])pens, however, other constrictions have 

 taken ))lace below, thus forming a chain of nearly mature conidia 

 adhering end to end. Under favorable conditions they germinate 

 (|uickly, .<<ending out a slender tube, vhich, on the jn-oper host, soon 

 develops into a new u'ycelium. They are jiroduced in innnense num- 

 bers tlii'oughout the growing season, and, as they are very light and 

 easily carried liy t\w wirul, they serve for the rapid increase and wide 

 distribution of the parasite. 



The perithecium remains on the fallen leaves over winter. It is 

 not provided with a mouth or ostiolum of any kind. The contained 

 asci and sporidia only escape on its decay in the spring. 



Delicate membranaceous conceptacles, other than the perithecia. 

 are sometimes found in connection with the mycelium of the Erynl- 

 jihcie. They are thin-walled, and, on sliglit pressure, rupture irregu- 

 larly, emitting immense nund)ers of minute, oblong, nucleated spores, 

 immersed in a gelatinous fluid. They were noticed l)y Cesati, in con- 

 nection with the grajic mildew. Sujiposing them to l»e independent 

 organisms, he named them Aiuj)eIomycei< qn/sqvalis, and specimens 

 were published under that name as No. 1609 in Rabenhorst's Herba- 

 I'ium Mycologicum. Later they were iiaWed Cicinobolnn JlorentiiniK 

 by Ehreubcrg, and liyssocysfis textilis by Riess. Tulasne, Mold. 



