••6 



in Monotnypa. Tlic ruot-syslciii of a liee has not only to secure 

 nourishnieut, Imt also tlu' rigidity and stal)ility of the tree.^ 

 This latter can only be attained by a wide distribution of roots 

 in the firm subsoil free from humus, where normal roots with 

 root-hairs will be formed. Tlie nursing function of the niycorhiza 

 seems thus tf» be less important than in the case of Monotntpa. 



Fig. is. — Mi/corhi-.n nf Pi-iwa Crmdra. A, Tj'pical niycorhiza. B, Root showing 

 flustcis of mvforlii/ ( i v ■ 11 ,,s portions clad with fine root-hairs. C, Rootlet 

 exhibiting buttmi Ii Hi i ing.s externally devoid of a fungoid mantle, but 

 internally conipl't : I liy mycelium. 2), Section thi-ough a thickened 



branch of a myioi hi ■ i > li-t^ i- : a, fungoid mantle; l>, fungoid tissue between 

 the cells of the root, rendering them unrecognizable except by their large nuclei ; 

 the inner parts contain no fungi, (v. Tubeuf del.) 



]\Iy newest investigations on this subject ^ show that, amongst 

 the gymnospermous forest-trees, the Abietineae alone have roots 

 externally clothed with a fungus ; the remaining groups have 

 all endophytic niycorhiza. The Abietineae have frequently only 

 ji fine mantle of fungus on their rootlets, and do not produce the 

 tufts of short, branched roots so characteristic of mycorliiza in 

 general. Frank does not seem to be altogether correct in his 

 view that the Abietineae are almost or quite incapable of multi- 

 plication by slips, because they would then require to exist for a 

 time without niycorhiza. Probably there is some other reason 

 for this, because the Salicaceae (e.f/. Poplars), which have typical 

 coral-branclu'd niycorhiza, are almost exclusively multiplied l)y 

 slips. 



^ Hoveler, ("ilb. die Verwerthiing <1. Huniiis hei d. Eniiihrung d. chloropliyll- 

 fiihrenden Pflanzen." Inuug. Diss., Berlin, 1S92), states that roots are able to 

 utilize the soil-constituents without aid of fungi. 



-Tubeuf, For.sl.-natu7-ivi>is. Zeilschrift, 1896. 



