862 REPORT — 1903. 



3. On the Localisation of Antliocyan {red-cell sap) in Foliage Leaves, 



By J. Parkin, M.A, 



There is an impression, the author believes, amongst botanists that the pigment 

 known as anthocyan resides as a rule in the epidermis of the leaf. No extensive 

 investigation seems to have been made to see how far this view is correct. The 

 author has so far submitted to microscopical examination four hundred different 

 instances of anthocyan occurring in foliage leaves. The species investigated include 

 monocotylous and dicotylous trees, shrubs, and herbs, together with a few ferns. 

 The anthocyan of leaves can be divided into four main categories : — 



(1) The transitory anthocyan of young leaves, — This appears during the de- 

 velopment of the leaf, disappearing again on maturity. It is a marked feature of 

 tropical foliage, though it occurs less strikingly in many plants of temperate 

 regions. Number of species so far examined, 235. The anthocyan is confined to 

 the mesophyll in 64 per cent, of these, to the epidermis in 20 per cent., and is 

 common to both in 16 per cent. 



(2) ^ AutimnnaV anthocyan. — This appears in many old leaves as they change 

 colour previous to their fall. Number of species examined, 81. The anthocyan is 

 confined to the mesophyll in 78 per cent, of these, to the epidermis in ^11 per 

 cent., and is common to both in 11 per cent. 



(3) T]ie permanent anthocyan of mature leaves. — This appears as the leaf 

 matures, and persists throughout the life of the leaf as a normal character. This 

 category includes («) leaves with uniformly red lower surfaces ; (6) leaves with 

 definite pigmented areas in the form of spots, blotches, or zones ; and (e) leaves of 

 horticultural varieties, with coloured foliage. Number of species examined, 64. 

 The anthocyan is confined to the epidermis in 70 per cent, of these, to the 

 mesophyll ia 17 per cent., and is common to both in 13 per cent. 



(4) The accidental anthocyan of mature leaves. — In distinction from (3) this 

 is not normally present in the mature leaves, but arises only under exceptional con- 

 ditions, such as : («) excessive insulation, followed by cool nights, seen in Alpine 

 plants and in evergreens during winter; (b) the result of injury, a reddish zone 

 often appears round a wound in a leaf ; and (c) through the accidental exposure of 

 the lower surface to the full rays of the sun. The greater sensitiveness of the 

 under surface of the leaf to reddening is a fact of some interest and seems to have 

 been imrecorded. t 



Thirty cases have been examined, and in the majority of these the anthocyan 

 was confined to the mesophyll. 



In summary, then, the anthocyan of young leaves and of autumnal leaves is 

 usually confined to the mesophyll ; that of mature leaves, when a normal feature to 

 the epidermis, and when an exceptional one to the mesophyll. Thus the mesophyll, 

 i.e. the chlorophyll cells, appears to be the usual, and, perhaps, the more primitive 

 position for the red sap in leaves. 



The fact that anthocyan is usually present only in the mesophyll of young 

 leaves seems to weaken somewhat the view that its function there is to protect the 

 chlorophyll by absorbing the destructive solar rays. 



The author is inclined to think that the biological significance of this pigment 

 has been overrated, and that the majority of cases may be capable of explanatioa 

 on purely chemical or physiological grounds. 



4. The Forest Resources of Aihstralia available for British Commerce. 



By E. T. SCAMMELL. 



Forest conservation and development. — One of the most important duties 

 requu'ing the early attention of the Federal Government of Australia is that of 

 dealing with the forest resources of the Commonwealth. At present the forest 

 ]aws and regulations in force, according to the judgment of the Victorian BoyaJ 



