THALLOPHYTA. 691 



containing eggs. Here the chambers, instead of being numerous and deliquescent 

 as in Lycoperdon, are few and provided with thick, hard walls; they arise in a 

 matrix which occupies the whole body of the Fungus, and when mature they 

 become isolated by the disappearance of the matrix. Each chamber is attached 

 by a string to the wall of the peridium (c/. fig. 391 '). The opening at the top 

 arises by the coming away of a membrane which previously closes it in. Perhaps 

 the most remarkable group of Gasteromycetes is the Phalloidece, which includes 

 the common Stink-horn Fungus and other forms. Whilst immature they are egg- 

 like, but at ripening the investment bursts and the remarkable gleba is hoisted up. 

 Clathrus (shown in fig. 391 ^) has its gleba spread over a hollow spherical lattice- 

 work; the gleba is red in colour and the appearance of the Fungus very striking; 

 it is rare in this country. The Stink-horn, Phallus impudicus, is less rare. When 

 the gelatinous investment bursts, a spongy, spindle-shaped stalk expands and raises 

 up the green, cap-like gleba. The Phalloidess depend upon insects for the dispersal 

 of their spores. Flies are attracted by the bright coloration and foul smell of these 

 Fungi, and they lick up the mucilage into which the gleba deliquesces with great 

 avidity. Perhaps ■ the tropical Bictyophora phalloidea is the most remarkable of 

 the group. It resembles a Phallus, but unfolds around itself a delicate white 

 network which hangs expanded from below the gleba-cap like a crinoline. It is 

 thought that this appendage — like the white corolla of a night-flowering plant — 

 renders the Fungus additionally conspicuous after dark. The Phalloidese, in re- 

 ference to their marked attraction for insects, are sometimes spoken of as the 

 " Flowering Fungi ". 



ADDITIONAL GEOUP OF FUNGI. 



LICHENES. 



In our review of the various alliances and families of Fungi the fact has been 

 from time to time noted that certain members of various groups live symbiotically 

 with Algae as Lichens. Though obviously all these Lichen-fungi do not constitute 

 a natural group or alliance, we propose treating them for convenience together. 

 The general characters of Lichens and their mode of life have been already indicated 

 in the chapter commencing at vol. i. p. 243; consequently little but an enumeration 

 of the groups of Lichens and their methods of reproduction is required now. Briefly, 

 a Lichen consists of a Fungus and an Alga upon which the Fungus lives parasitically. 

 But it is something more than a mere parasitic Fungus on a green plant. The 

 mycelium involves the Alga in the most complete manner (c/. fig. 392), but it doesn't 

 kill it like an ordinary parasite. It lives upon the organic food which the Alga is 

 able to manufacture in virtue of its chlorophyll, but without obvious injury to the 

 Alga. Indeed, the algal cells often attain to a larger size and greater brilliance of 

 colour than when growing freely. On the other hand, the Alga is nowhere in contact 

 with the substratum (being inclosed in the substance of the Fungus), so that water 



