I Hi: CYANOPHYI l..\l ."ill 



relationship. The manner in which typical chl"r<.phyHou> plant- 

 gradually become shelter-para-ite-. an, I j a-- ti,,m this int.. the 

 condition of true para-ite-. i> \\.-ll <lt-ni..n>trat.-.l amoiiu-t the 

 algae. Few of tin- parasitic alg ;n be said to atlect their 



host injuriously l.y causing death of it> tissues; J'/ii/ll,-*iji/i,.,, is 

 the most marked rase of this kind. 



.1. THE CYANOPHYCEAE. 



These, the blue-green algae, possess a h..ni..-vn.,ii- hlui-h 

 given plasma. with a colouring matter con-i-tini: of ]ih\.-...-yan 

 and chlorophyll. Multiplication takes place only bv <vll- 

 division; sexual reproduction docs not occur. Manv of the 

 foints are adapted t.i a symbiotic life, yet without prejudice to 

 I heir ability to li\e as independent organism-. Numer>u> 

 speeies form lichens. They are in many cases capable ..{' long 

 resistance to drought. 



The Cyanophyceae arc common both as endophyto and 

 epiphyte- mi othe) algae and on higher ]>lants. Amount them 

 will be found examples of purely shelter-parasitism, of true 

 }>ara-iti.-m. and all intermediate stages, \ et no cases are kiio\\n 

 of real injury r death to host-plant- ivsulting fiom members 

 of this group. Amongst forms endophytic in I'haneio-ams may 

 be noticed Nostoc gunnerae in Angiosperms, and Andbaena 

 ci/r/i/l,ii ruiii in ( iymiio-peinis ; in rterid..pli\ ta only Annl,i,n 

 n-.oliin is known, and in I'.ryophyta, Nbstoc lirlnm.nl,>. In e\.-i\ 

 case the A'.s/nr penetrates as a shelter-parasite into ti-siire- or 

 cavities already exi.-ting in the host, and become- a.- a rule 

 entangled in a slime occupying the cavity. The -V I in 

 Gunnera becomes para.-itic at a later stage, and make- it- \\ay 



into the cavity of celN. The other .-pecie- are ne\ei endophytic 

 in the lio-t-cells, though ilie\ ina\ alfcct the cell- -ii rroii ml ing 

 a cavity and stimulate them to further growth, apparently. 

 however, without any injurious elfect ..n the host-plant. 

 Nostoc punctiforme (Kutz.) I', llaiiot 1 A i >'///. 

 i/i/iiin fit' 1,'einkei. Thi.- oeeurs in \aiioiis sjieeic- of Gunnt 

 native,- of South \fiica. Ne\\ /calami, and South Amci 



cultivateii fie(|iientl\ in Kun.pe The occurrence of the A 



i- III e\e|\ CaSe the -allie it- prc-elice bcillg indicated to [ he 



1 .. < . ,! -. , , \\.. 



!: ink"-, M"i / A../...'/-, .'i- Aliha diu \ : . I S 7.'! 



