ii6 



RESEARCHES ON FUNGI 



The area of a fruit-body is increased by marginal growth. 

 The peripheral walls of the iuterlaniellar spaces protrude outwards 

 as crenatures, and more or less resemble the heels of slippers 

 placed side by side in a row (Fig. 4;')). These crenated walls 

 constitute growing regions by means of Avhich the older gills arc 



lengthened and new 

 ones added. Whilst a 

 pileus is extending by 

 marginal growth, the 

 interlamellar spaces 

 gradually widen. 

 When a space has at- 

 tained a certain Avidth, 

 it Dccomes divided into 

 two down the middle, 

 owing to the formation 

 within it of a new gill 

 which arises as a short 

 median downgrowth 

 from the pilous flesh 

 (Fig. 413, a). The upper 

 half of every new gill 

 is undivided, but the 

 lower half is made up 

 of two plates, the inner 



Fig. -13. — Schizopkyllum commuiie. Piece of a pileus seen r i • i 



from below sliowin^ the arran-jement of the gills. SUriaCCS 01 wllicll are 

 a-(j, stages in gill development; h. part of"^ the ;„ pr-^it-iPt -ind plntliPrl 

 woolly layer covering the top of the pileus and here ^" conLaet auu ClOUiea 

 extended over the pileus margin ; i, interlamellar with loOSC hvuhai (cf 

 space. Semidiagrammatic: the gills are represented , ' ^^ '' _ * 



as cut through transversely so that the surfaces of Fig.41.E). Agill,whilst 

 section lie in one plane. About 13 times the .\, , , 



natural size. Still very short, occu- 



pies an isolated, sub- 

 terminal position within the interlamellar space in which it has been 

 formed. However, as growth proceeds, its distal end gradually 

 approaches the pileus margin and eventually joins with it 

 (Fig. 4."), a-f). All gills at their first-formed, stipe cuds are 

 shallow and only partially divided. However, at their peripheral 

 growing ends they gradually become deeper and more divided, 



