HARDWICKE'S SCIENCE-GOSSIP. 



229 



cells, presenting the appearance of ordinaiy cellular 

 tissue. The tissues of fungi are invariably cellular, 

 but the cellulose is peculiar, inasmuch as it does 

 not in general become blue on the addition of iodine 

 and sulphuric acid, whereas other cellular tissue does 

 so, although much more difficult to demonstrate than 

 the blue reaction of iodine on starch. In some fungi 

 the asci and spores become blue when iodine is 

 added. Laticiferous vessels are abundant in some 

 groups : the 

 genus Lacta- 

 ritts is charac- 

 terised by the 

 milky gills, 

 which, on 



being injured, 

 give out a 

 copious sup- 

 ply of latex, 



usually white at first, but often changes 

 colour to yellow, lilac, green or blue on 

 exposure to the air ; the latex is some- 

 times insupportably hot and acrid, in 

 other species sweet. When the spore- 

 bearing surface is continuous over a 

 considerable space, it is called the 

 hymenium (fig. 137). The following 

 examples illustrate the most marked 

 types of structure : — 



Sporifera. 



This division includes four families. 

 The first, Hymenomycetes, is character- 

 ised by the presence of a continuous 

 hymenium, which, from the first, 01 

 very soon, is exposed, and spread over 

 closely arranged plates, or gills, spines, 

 lining the inside of closely packed 

 hollow tubes or pores, or covering uni- 

 formly the whole surface of the plant. 

 Mushrooms and "toadstools" stand 

 at the head of this family, and will serve 

 as a type. The stem and cap, ox pi leu s 

 together form the hymeiiophore (fig. 138, 

 f, e), the under side of the pileus is 

 broken up into gills, radiating from the 

 stem to the margin (fig. 138, g). These 

 collectively constitute the trama, over 

 which the hymenium is spread. The structure of the 

 trama is often different to that of the pileus, which in 

 turn differs from the stem, the latter frequently being 

 more fibrous and often hollow or loose in texture 

 towards the centre. The hymenium presents under 

 the microscope the following parts, a groundwork of 

 cells, basidia with their four spicules, terminated by 

 spores, and in fewer numbers, yet thicker and more 

 elongated cells called cystidia, whose functions are 

 not yet ascertained (fig. 134, c). All these may be well 



studied in Agaricus ienacellus or Coprinus comatus. 

 The higher mushrooms — agarics — when quite young 

 are enclosed in a continuous skin, which as the stem 

 lengthens is ruptured, one part remaining as a sheath 

 more or less grown to the base of the stem, and 

 called the volva ; the other part is carried up by the 

 pileus, on the top of which it sometimes remains in 

 the form of warts or irregular patches (fig. 138 a, b). 

 Before the fungus has arrived at maturity, it will be 



observ- 

 ed that 

 the gills 

 are not 

 visible, 

 but the 

 edge of 

 the pile- 

 . u s is 

 connec- 

 ted with the stem at some distance from 

 the base by a membrane, the veil 

 (fig. 138, a) which is ruptured as the 

 cap increases in size, portions some- 

 times remaining attached to the margin ; 

 but the greater part forms a collar 

 round the stem, and is called the ring 

 or annulus (fig. 138, c). The covering 

 in which the young plant is enclosed, 

 and which on the growth of the fungus 

 becomes the volva, and warts on the 

 pileus, is also known as the universal 

 veil, and the membrane extending from 

 the margin of the pileus to the stem, 

 the partial veil ; one or both are absent 

 from entire groups of agarics. 



(To be continued.) 



BOTANICAL RAMBLES FROM 

 BRADFORD. 



By William West. 



BRADFORD is a large town, and 

 if we set out from its centre we 

 have to go two miles in almost any 

 direction before seeing anything but 

 such plants as Lolium perenne, Poa 

 annua, Polygonum aviculare, &c. If 

 we take down the valley we shall find something 

 worth noticing very near the town, for here, near the 

 canals we have fields nearly covered with Polygonum 

 bistorta, where I have seen the roots being taken away 

 in sacks for the herbalists ; a little farther on, Sangui- 

 sorba officinalis sends up its pretty leaves, then Epilo- 

 bium angustifolium is seen, and we begin to notice 

 things, for we have a canal, some ponds, a wood, a 

 stream, a railway embankment, and some quarries 

 not far off. In the ponds and canal, and on their 



