406 



COMPARATIVE MORPHOLOGY OF FUNGI 



istic for the individual species and afford important diagnostic points 

 (Fig. 268, 1). 



The vascular hyphae (Fig. 269, 2) form the real conducting elements; 

 in their formation the hyphae swell, increase the diameter of their lumen, 

 thicken their walls, dissolve the septa, transform their clamps to open 

 tubes and increase their resistance to pressure by ring and spiral thicken- 

 ings and by moniliform trabeculae across the lumen. Functionally, they 

 are comparable to the sieve tubes of the flowering plants. The fibre 

 hyphae are the mechanical element of the rhizomorphs. As a rule they 



Fig. 269. — 1. Coniophora cerebella. Two whorls of clamps, the lower of which has 

 developed branches. 2. Lenzites abietina. Portion of vascular hypha. S, former clamps ; 

 H, unaltered parts of hyphae. (1 X 500; 2 X 240; after Falck, 1909, 1912.) 



surround the vascular hyphae on all sides as a protective coat; their walls 

 are considerably thickened with a corresponding diminution of lumen, 

 their septa and clamp connections are degenerate, contents are conspicu- 

 ously lacking; in short they resemble closely the wood fibers of the Cor- 

 mophyta. Similar relationships have been determined by Bambeke 

 (1901, 1914) for Lepiota meleagris and Phallus impudicus. Occasionally 

 the mycelial threads do not function as conducting organs, but acquire a 

 more sclerotial structure with white core and brown, brittle, pseudopar- 

 enchymatous rind ; the individual hyphal elements give up their individ- 

 uality entirely and apical growth follows by an apical meristem, as in 



