USTILAGO. 293 



Ust. grandis Kiie-. Heed-smut. < I'.ritain. i Thi- frequents the 

 haulms of Pli /"///// //, x coinmunis (aNo '/'//////" A////;///*/ ami /'. 

 //"'//'//); the internodcs of tin- host in consequence -\\t-ll out 

 ami appear as if the stem carried one .r more bulrush -heads. 

 The mycelium peimeates the whole ho-t-ti--iie and produce- 

 spores, \\hii-h escape as a Mack dust mi rupture of the epideimi-. 

 Accordiim t'> Kiihn, the spores are capahle of immediate ger- 

 mination and retain their vitality for a whole year. A 



J 



four-celled promycelium is ]rudr.crd and becomes detaeln-d iriim 

 ilu- -pure: then follows an ahjunetioii of ohlonu emiidia from 

 thf -i-pta of the i>ri nnvcflium. In nutritive solutions, I'.ivfrld 

 1'i'Uiid that urrmination took jilace in the -ame \vav, Init nmre 

 rajiidly and vigorously. Numerous eonidia are produced, hut 

 these only rarely '_:ive of!' secondary emiidia, and then only a 

 -nude one : more eominonly they produce promveelia. as the 

 did, and eonidia a-ain arise Irom these; y.-a-t-liki- 

 does not occur. The rest in^-sp ( . res may ci.ntinui- 

 to -i\-e off promveelia in suecfs.-ion for some time. ( h\ ex- 

 haustion of nutrition the cells of the promyeelium. as well 

 as the eonidia, develop into mvcelial threads, to which alone 

 I'.refeld ascribes the cap.-icity for iiifectiun. 



Ust. longissima (Sow.) < I'.ritain and I'.S. America). This 

 forms elongated In-own -p"ie-p;itches on the leave> of various 

 specie-, of Glyceria. I'.iefeld states that the -month spherical 

 > pi .res 'jerniinate in water, and ^ix'e otf a ^\\\-[ unicellulai- 

 promyeelium which undergoes no further development. In 

 nutritive solutions the spores -erminate in like manner, hut 

 the promycelium liecomes l hivad-like and septate, and gives 

 off eonidia laterally: new promycelia continue to he -iven 

 off from a cell which remains hehind in-ide the spore, and the 

 eonidia ultimately develop into hyphae. 



Ust. hypodytes (Schlecht). This specie- form- dark smutty 

 '.: "ii haulms and leaf-sheaths of (,'///<; //,/ jliiitiiii*, l>i/i- 



lachnis fusca, .}</r<i/i///n/ii repens, Calamagrostis >j>i;/"'. 



a i-, mi riii , Sti/ni i>,,<iuihi and X. capillaris, /.'/"// ctus, '/'-it 



npens and '/'. /-//A////-., El ///////.-.- arenarhis, /'n/ii'-mn repens, /'/< 



communi Arundinaria, etc. Tip spores are l>i<>\\n. 

 smooth- walled, ami in-e-ularly -phcrical or quadrangular; they 

 ainate in uater or nutritive solutions, piducini: m\ei-lia 

 direct, \\ithoii 1 previous foimatiou of eonidia. 



