zooLoay and botany, microscopy, etc. 627 



spirally coiled. In Lactarius, Mycena, and some Polyporeae they contain a 

 true latex ; in other Polyporeae and in Fistulina a fluid containing tannin ; 

 in some Agaricinese again they contain a more or less clear sap. Their 

 origin is usually the same, as lateral buddings from mycelial filaments. 

 Their distribution varies greatly, and may be arranged under three types, 

 viz. : — 



(1) The iac/anus-type. In most species of this genus the greatest 

 number of latex-tubes occur in the subhymenial layer, and in the periphery 

 of the stipes ; the former branches on the one hand into the hymenium, 

 on the other hand into the tissue of the pileus. According as the cortex 

 consists of one or more layers, these tubes are also in a single or a double 

 layer. In the pileus they run either parallel or obliquely to the surface of 

 the lamellae. 



(2) The Mycena-ty]^6 is much more simple. The latex-tubes are ex- 

 tremely long, running through the periphery of the entire stipes, and ending 

 in the central tissue of the pileus. There is no subhymenial layer of 

 latex-tubes. 



(3) The Fistulina-tjT^e. The latex-tubes are distributed through the 

 entire receptacle, and are not collected in definite spots ; comparatively few 

 are found in the hymenium. 



The latex-tubes pass by insensible gradations into the oil-receptacles, 

 which differ from the former more in their contents than their form. The 

 substance contained in them is usually dense and strongly refractive during 

 the greater part of their period of growth ; though in some species of 

 Stereum and Corticium it is a turbid fluid. These tubes are always undi- 

 vided and seldom branch ; their walls are thin and soft ; the parietal layer 

 of protoplasm can be detected throughout their existence, and often contains 

 several nuclei. Their form is either that of long tubes, short cells swollen 

 into a club-form, or spherical cells. They are formed in the same way as 

 the latex-tubes, often in the mycelium. 



The pigment-receptacles show no sharp distinction from the oil- 

 receptacles. They occur in many species of Lactarius and Mycena, where 

 the substance is of a very similar nature, and often assumes a bright 

 colour only on exposure to the air. In many poisonous species of Boletus 

 they contain the poisonous principle dissolved in the cell-sap. These 

 receptacles are usually slender much-branched, tubes ; they are most 

 abundant in the periphery and basal parts of the stipes, but occur also in 

 the pileus and hymenium. 



Cystidia of Fungi.* — Dr. E. v. Wettstein regards these structures of 

 the Hymenomycetes as having very different physiological values in the 

 different genera. In Coprinus they are at first protective organs for the 

 young spores in the course of their development. In the mature receptacle 

 they serve partly the same purpose, or they fuse together, or force them- 

 seves into the neighbouring lamellae, preventing the rupture of the pileus. 

 The author considers them as but of little value for taxonomic purposes. 



Infection througli parasitic Sclerotia.t — Herr J. H. Wakker has 

 closely investigated a disease which is very destructive to hyacinth-cultures 

 in the neighbourhood of Haarlem. It makes its appearance after the time 

 of flowering, causing the leaves to turn yellow and fall off. No mycelium 

 can be detected in the parts above ground, except at the very base of the 

 leaves. The roots have often died off altogether, and the bulb is com- 



* Verhandl. Zool.-bot. Gesell. Wien, sxxvii. (1887) p. 6. 



t Bot. Centralbl., xxix. (1887) pp. 309-13, 3i2-6. Cf. this Journal, 1883, p. 686. 



