KI miKd'Hlr MYCoiMlIXA. '.'7 



After tin- mycorhiza have functioned as such for -ome time, 

 tin- fun-oid sheath, as well as the hyphae contained in the 

 cortex of the mot outside the endodermi-, an- thrown o|f }>\ 

 internal cork-formation. This is, however, not always the 

 lor the fun-us may penetrate further ami develop injurious para- 

 sitic characteristics; this is so with /W//.s^r///// ' and A'//>/in,/i< . 



Endotrophic Mycorhiza. 



(1) On non-chlorophyllous plants living in humus. 



Certain Orchideae J\'< /.///,/ A7'///x avis, A/////<"/"/> Gmelini, 

 Goodyera repens, etc., as well as some- ( lentianeae.- ; possess 

 root- developed as eiidotrophic mycorhi/.a. In < '<n-U'n< ////;' the 

 fungus frequents the short coral-like rhi/onie-. The fun-us in 

 ;h'-se cases penetrates into the cells ,,(' ihe root-cortex, and 

 there (onus a oall or coil of hyphae ; it neither covers the 

 routs externally nor inhabits the epidermal cells, so that the 

 piodiiction of root-liaii's uoes on quite normally. l-'roiu the 

 circumstance thai the hyphal coils become emptied and only 

 the remains of walls are left in the still living root-cells, r'raiik 

 concludes that the fungus after liein-- nourished for a time l>y 

 the root-cells is ultimately de]>ri\'ed ot' its contents 1,\- them. 

 <>n this account he calls these roots ''fungus-traps." and the 

 plants pos>essinu iheni " fungus-digesting plants." It must l.e 

 remarke.l, howe\er, thai the fungus -rows onwanis from older 

 parts of the roots to yoiui-er, so that here, as in many other 

 cases, the contents of the hyphae may pass from the older into 

 the younger hyphae. Frank himself suif-ests ' the possibility 

 that the roots take up nutriment without aid from the cndo-ed 

 fun-US, and also that the latter receives its food para-ilically 

 from ihe former. What advantage the roots may receive from 

 icalisorptioii of food, which they have previously supplied to the 

 fungus, has not lieeii closely inve-t i-atcd. nor ha- llie ijiie>iion 

 \\hcther the roots are in a po-ition to imiiri-li the plain- equally 

 wi-11 without fiin-i. 



The root-funi of Orchideae have Ion- heen kii"\\n. and I'feifci 



"Beitrag /. K. nnini-- .1. (J.-iiiun. Polyaaccnm," Flora, 



I:..- , I 'lit, i Midi, ulirr <l. Ilii -M-liii nil'i-1," Bibliog. Bota\ l^s7 

 Pringheim't ./"/(//. /"//, \\i. ;unl \\. 

 '1'i.ink, /.> lu'liiii-fi f/. I!/, 'a,,;/.' p. I'liT. ' /.iiii'/ii-;,-tfi. .Inltil'iK-h, 1^77. 



