242 



THE NATURE BOOK 



The Xylaria Hypoxylon (ord. Sphcrri- 

 acece) is corky in substance, and is either 

 simple or branched. The photograph 

 shows a growth, in the right-hand top 

 portion, branched cUstinctly into three, 

 as well as many examples of the simple 

 form. The branching extends consider- 

 ably beyond this, the group representing 

 the plant in an early stage of growth ; 

 it is then pulverulent on the surface, hav- 

 ing a white mealy powder upon it. which 

 later on disappears and the colouring 

 becomes black. 



The black base is clearly distinguished 

 in the foreground group to the left of the 

 picture, where the tree-stump is sliced 

 off at an angle. The two leaves in the 



immediate foreground are of value in 

 suggesting the size of the Fungus. In 

 the stages of its growth, the Xylaria 

 expresses something of the advancement 

 of all plant growth onwards from a 

 primitive, or very simple blunt form, 

 to the more complex one of extended 

 branches and branchlets upon those 

 branches. In the simple blunt form 

 that first arises there is a conglomer- 

 ate of cell-structure that, becoming 

 checked in its direct upward growth, 

 forces again forwards laterally and 

 vertically as two or more distinct 

 portions. These in their turn repeat 

 the impulse, adding to the character of 

 the plant. 



Maud U. Clarke. 



LIFE HISTORY OF A MOUNTAIN— I 



By J. LOMAS, F.G.S., A.R.C.S. 



THERE is a group of insects — the 

 Ephemera — whose lives are com- 

 passed about by a single day. In 

 the morning they are born, during the 

 day they go through all the functions 

 of life, and die with the setting sun. 

 Imagine one of these creatures, en- 

 dowed with powers of thought and reason- 

 ing, spending its brief existence on an 

 oak tree. Of its own knowledge what 

 could it know of the acorn, the unfolding 

 leaf, the bare branches and winter's snow ? 

 It would naturally regard the oak tree 

 as the ver}' emblem of stabihty — immu- 

 table and everlasting. 



So man, when he considers the Earth 

 on which he spends his little day, would 

 be prone to look upon the features of 

 the Earth's crust as unchanging, if he were 

 guided solely by the light of his own 

 experience. Even if he were acquainted 

 with the accumulated experiences of past 

 generations as recorded in the writings 

 of his predecessors, the changes would be 

 so slight that they would scarcely be 

 noticeable. 



But the Earth has written its own story 

 in the rocks of wliich it is composed, and 

 if we can read only a little in this great 

 " Nature book " we find that the dominant 

 note is not stability, but change. 



Mountain, valley, river and sea are 

 only the present-day phases of many 

 scenes which have begun and ended in 

 the past. Tennyson's well-known lines 

 record a scientific fact : 



" There rolls the deep where grew the tree, 

 O Earth, what changes hast thou seen ! 

 There, where the long street roars, hath been 

 The stillness of the central sea." 



In the great operations of Nature, time 

 is an important factor. Changes may be 

 going on about us with such exceeding 

 slowness that we do not perceive them. 

 In our blindness we speak of the " ever- 

 lasting hills " and " the ever-changing 

 sea," and yet by a strange irony the sea-" 

 level is the only datum line which can 

 be regarded as apjiroaching to stability, 

 and it has been universally employed as 

 a means of recording the height of the land. 



