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would be no food. In waste districts of Africa and Western Asia 

 the edible lichen, Lecanora esculenta, or •' manna of the desert," is 

 of great value as food for man and beast. ^Several near relations 

 of this plant — that is to say, several species of Lecanora, are to be 

 found in our own neighbourhood, but they are not at all like their 

 more useful brother. The desert manna is said to be never attached 

 to anything, so that it must live almost entirely upon air. The dyer 

 uses several lichen-products, such as litmus, archil, cudbear. They are 

 not exactly obtained from the plants but rather prepared from them 

 by the action of certain chemicals. The litmus referred to is the 

 substance from which are obtained the blue solution and paper 

 which the chemist uses as a test. Beginners in chemistry will 

 remember that acid solutions change the blue colour to red. The 

 use of chemical processes in obtaining the dyes seems to favour 

 the idea of chemical tests as a means of distniguishing one species 

 from another. In Lapland, the " Iceland Moss " — pray let it be called 

 Iceland lichen — and the " Reindeer Moss " (lichen), are simply in- 

 valuable, the latter being used as food both by the reindeer and by 

 man. The Iceland Moss (' etraria islandica) is abundant in North 

 Britain, and the Cladinarangiferina (the Reindeer Moss), even reaches 

 the southern counties of England, being abundant upon heaths in 

 some parts of our own county, though not occurring very near 

 Folkestone. This neighbourhood is good for the lichen collector, 

 as it is well known to be for the field naturalist generally. As 

 there are grasses that grow in the sea, so there are inter-tidal 

 species of lichen, but none have been observed on this coast. It is 

 known that fungi cannot do with sea water, and this fact 

 goes against the Fungus-alga theory. Generally speaking, 

 lichens are not looked for in wet places at all, although they might 

 be expected to abound there if the holders of the fungus-alga theory 

 have truth on their side. But why, some enquiring member of this 

 maeting may ask, should not plants that live upun water live in 

 water — why should they not be submerged or floating aquatic 

 plants, and so be sure of constant supplies ? This question brings 

 out facts of great interest, and which do not apply to any other 

 class of plants, for the truth is that lichens live a life of a very 

 peculiar kind. They grow fairly fast for a time and then move 

 very slowly indeed, clinging to life through long periods of drought 

 and under conditions that would be fatal to plant- life generally. 

 Associated with this power of resistance, is length of days for it is 

 startling to record that lichen life is not to be reckoned by hours 

 (as with some Fungi), days, weeks, months, or even years, but by 

 tens, and even, we are assured, hundreds of years. In hard times, 

 it is very sluggish, the plants " holding their own " bravely until 

 better times come, when they revive and look young again. The 



