ALGM. 



place, by which the threads come to consist of ,pvp™i . c „ 



of division contain a homogeneous or granu ar proIoDl sm f K, '^k ""'^ '^"^ ^^P^' 

 brown colour, consisting of a minture^of ct r'o;h7 ^h th: b^f cT'" "■" '^"'^ 

 already mentioned or with a yellow one Tn n«.iL^ ! colouring substan 



thread are alike; the thread Ll is c^^indric^ „d ;hetV'r"'"K^'' '""^ ^^"^ °' 

 short transverse discs. In the other ^enera the thread, ,"' *' ^PP«-ance 



spherical or ellipsoidal and of two different forms h JIT ' "r"''°™' ">^ ^^ 

 capable of division; between them occur a ™ 'ter df """^ber are green a, 



thread, colourless cells of considerable sl^ Lf tf'^'f^' «■• « the end of tl 



The Nostochine. live in ^'atrTr Ire conl '"?''"'/''''"*"' '''^ ""^'^^^V^' 

 walls, where they form ge.atin^lsIcTrat onTo Ist'TheToir^ ^°t' ^' 

 IS known only in a few genera of this division '^ ■•eproductK 



Nostoc, which may be considered the tvne nf ia-„.* 

 of a large number of moniliform threads i„.e ^°^*^''^^^' <=o>«'st=. when matur 

 bedded in a glutinous iellv and Zs nnit^H .'"f™T'" """"^ ""'= ''"°">^'- «"d in 

 New colonies are, accor*n'g to Thurerf '!, '°L°"'f "^ ^ ^P*^'^"''^^"^ '^^^fi-'^d f"™ 

 the old colony b;cores oft ned b I'atr The' nort' T'^k' 7"— ^he jelly < 

 the heterocysts become detached sen" rUe from'^th n ^l "■'''* '^'"« ''^'^^'^ 

 while the heterocysts themselves rema^irth i^v Aft 'I.'k '"■"«"™ ""="'"'™' 



increase the number of their eel thrthen . '°"u""" '" '''°"«="^ ^"^ " 



contact with those of the next oJ/ndthTr'' "k'T '''"" '^™ '^™''"=" ^^"^ " 

 Nostoc-filament. Indi,idtnrcols nn!, „ u "*"'' """' '"'° '' ''"^'^ '^""« 

 cysts. In the meintin e 'e .. ' 'PP'''"'">' ^^"h""' m definite law, become hetero- 



the original,; ™:^Ti,'tbTtanr'::T"''' "'''"' ""^ '"^'"^"' '= ^'^^'^P^"' »^ 

 continuous h^crease .^XSlTdi^rs^Tthrelir^'^^ ''' '^ °^ ^ -^'^ ^>- 

 R.wl^l!7/°^ 'T ''^^*P'"'"' °f Hlvularie^ has been observed by De Bary 



the thread docs nT' '"k^'T '°"'"*=" '° " riding-whip. The pointed end of 

 of the t™sverse dl'™"' "' "'^ '""g'tudinal growth and the increase in number 



FructLaton takes olaT' ", ™' /"''"'''" ''°-"™'-'^^ - f- - the basal cell, 

 ructmcat.on take s place nearly simultaneously in most of the fi laments of a colony. 



lower slTo^fTelh Xrt/r"''"',""^'"" by Janczewski to enter the young stomata on the 



tTclTn B L^ia Pent n T? 7 " ' '"« "■"' '" ''''"''' ^""^ '" *^ "«"- ""ifferent Hepa- 

 gemi"of thTs; sne t 'n r"'' T- ''"""^' '"' """^ e^"=^^"^ t==" ""='d--'d endogenous 

 thewll' '^u ; ",. J™""""^' P™^-<=<3 'heir true nature. Nostoc also establishes itself in 



If th/Sr f r ! ■? . ' ''"■=' of Sphagnum. The entrance of Scytone,ne=B into the parenchyma 

 manner The ,: *^°'>:''^°"°"= ?'»'• ^--era, is brought about, according ,„ Reinke, i„T differ nt 

 WsTf ^'^T" ""' P"f "'=h>--<=<>"^ °f *e circumference of the stem, themselves covered by 

 and ,T PJ^^"t>™;' "' <'f ?<='y filled with colonies of the Alga. (Bot. Zeitg. 1872, pp so 

 l\\ I J''° ^""- '^'' ^"- ^'"- '^7'- P- 3°«. ""d Q«"t. Journ. Micr. .Sc. ,8,;, p ,60 1 

 [Archer has described the occurrence of -spores' in Nostoc paludosum which were alwavs 

 placed singly between Ihe heterocysts. Quart. Joum. Micr. Sc. 1S72, p. 367._Ed.] ^ 



