CHAPTER V.—COMPARATIVE REVIEW.—HYMENOMYCETES. 299 
defined than the strands of slender hyphae; they are often much elongated in the 
stipe and not unfrequently branched in the longitudinal direction or anastomose with 
others. In transverse sections, especially in the stipe, the cells of many of the large- 
celled portions are ovoid or wedge-shaped, and are so arranged, usually five or six 
together, round a centre that their narrow ends converge towards it, and they thus 
form a rosette on the transverse section. The cells thus arranged either form the 
large-celled group by themselves, or they are surrounded by one or more irregularly 
concentric layers of roundish cells ; other groups show two rosettes in the transverse 
section, others again show no indication of arrangement in rosettes. The small 
circular centre of the rosettes is formed by the transverse section of a narrow, 
cylindrical, thin-walled hypha with limpid cell-contents, which runs longitudinally 
and usually in a very winding course through the groups of large-celled tissue, as 
appears in a longitudinal section. The laticiferous tubes which are characteristic of 
Lactarius run through the strands of fine hyphal tissue, both close beside the large- 
celled groups and at a distance from them, but without ever entering them. These 
tubes have a large diameter as compared with that of the surrounding hyphae and a 

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FIG. 136. Lactarius subdutcis, Fr. Outer region of the stipe. al I section. 5 section ; 
o surface ; 2 laticiferous tubes. Magn. go times. 
very soft and extensible membrane, and they are filled to overflowing with a finely- 
granular turbid latex which is differently coloured in the different species and oozes 
out in large drops from the injured Fungus. The latex coagulates at the temperature 
of boiling water and when treated with alcohol. It is therefore advisable in examining 
the course of the tubes in sections to place the Fungi for a short time in alcohol ; in 
order to make preparations through the isolated tubes, the parts of the Fungus should 
be previously boiled a short time in water. Such a preparation shows that the tubes 
send out numerous strong branches in every direction, which often form H-shaped 
connections between two primary tubes, but never give rise, as far as I have observed, 
to a net-work with narrow meshes. Here and there the stronger branches put out 
short and delicate branchlets with very slender closed blind extremities. In older 
specimens especially the laticiferous tubes are not unfrequently divided by single septa 
placed at a considerable distance from one another. These organs traverse the hyphal 
weft of the whole of the compound sporophore and their finer branches extend to close 
beneath its surface. 
