V>- 



f 



THE FORMATION OF HYPHAL FUSIONS 67 



respectively and were correctly conceived, as shown by my observa- 

 tions on the actual formation of fusions in developing mycelia. 

 However, her first type of fusion, an end-to-side one, I am unable to 

 admit and have no doubt that the fusion which she had in mind and 

 illustrated in her diagram was in reality a hypha-to-peg fusion, i.e. 

 an end-to-end fusion. Finally, it may be remarked that Mile 

 Bensaude did not include in her classification the peg-to-peg fusions 

 described in this Chapter. 



Hein, 1 in 1930, as a result of studies made " on material prepared 

 by the usual fixing and staining methods as well as on fresh material " 

 came to the conclusion that in Psalliota 

 campestris hyphae frequently anasto- 

 mose with one another laterally. Thus 

 he 2 says : " Anastomoses occur apic- 

 ally and laterally between hyphal „ ,„ „ 



^ J x Fig. 43. — Coprmus fimetarius. 



branches from the same spore and be- Diagram showing the for- 



, 1 __i j -ij. ■,.„ mation of an anastomosing 



tween hyphae produced from different branch between two parallel 



Spores " and, further, in respect to the hyphae by means of an end - 



x to -end fusion of two lateral 



formation of the large hyphae of a branches. As indicated by 



v -i t , u TTT1 . the position of their second- 



mycehal cord, he says : Where two ary se pt a) two clamp-con- 



or more hyphae fuse by the dissolution nexions belong morpholo- 



J *■ J gically to the hypha a and 



of their lateral adjoining walls as in two to the hypha b. Drawn 



-,-v ,~ ! , n <> i t an d described by Mile 



.rigs. 12 and. 13 a cell of large diameter Bensaude. 



results. In this manner the vascular 



elements of large diameter originate. The large lumen in the vas- 

 cular hyphae of Psalliota campestris does not appear to be entirely 

 the result of swelling as Falck described for species of Merulius 

 (1912), but is at least partly the result of lateral fusion of hyphae of 

 smaller diameters." In his Fig. 14 he 2 represents the tip of an older 

 strand and concerning it remarks : " The hyphae are all of uniform 

 diameter, filled with protoplasm and actively growing. These are 

 the ' Bildungshyphen ' of Falck (1912). The latter hyphae will 

 become differentiated by lateral fusion into vascular hyphae of 

 large diameters." 



1 I. Hein, " Studies on the Mycelium of Psalliota campestris," American Journal 

 of Botany, Vol. XVII, 1930, pp. 197-211. 



2 Ibid., p. 203. 



