Correspondence 



275 



CORRESPONDENCE. 



Fibro-VASCULAR Bundles. — A skeleton leaf shows very well 

 what is meant by this expression. The parenchyma and epidermis 

 (outer covering) have been removed, and the fibro-vascular bundles 

 alone remain. The parenchyma is composed of cells not much 

 longer than broad, which present broad surfaces to one another. 

 Pith, and also the soft parts of fruits, are examples of parenchyma. 



Darwin states that Hypericum crisftum will poison white sheep 

 but leave black ones unhurt. Query, do the black sheep eat it ? 



An observant farmer reports that the ox-eye daisy is injurious 

 to both sheep and horses. If its flowers be chopped up with hay 

 or straw for horses sore mouths will be caused, with slobbering. 



SCHOOLBOV suggests — respecting what we wrote on "leaf-miners," 

 see p. 162 — that if a word is wanted to signify that the larvae which 

 make their burrows in leaves do so in order to feed, it might be well 

 to call them "grub-burrowers." 



Mr. Benjamin Harrison, of Ightham, writes to us : I venture 

 to copy a note from my diary, September, 1904 : — 



Swallows' Nests. — The summer of this year being unusually hot 

 and dry, the mud necessary for their nests was very scarce. I was 

 startled one day to find the nests under the eaves of two cottages 

 adjoining my home fallen down, and young birds killed by falling on 

 the pavement. Not unlikely, the lack of cohesiveness caused the 

 bottoms to give way when the young ones began to struggle in the 

 nests. The nests were not rebuilt. Shortly after my attention was 

 drawn, by a workman, to a sycamore tree in a paddock close by. 

 Here a swallow had built its nest in the fork of a branch from main 

 stem. This seems very like reasoning on the part of the birds and 

 a start in a new direction. 



Vitality of Seeds. — To the disputed question of the vitality of 

 dried or buried seeds a new contribution has been made by M. Fliche, 

 a French botanist. In the forest of Hane some years ago he was 

 astonished to find large quantities of a plant called cypress-spurge, 

 or wolf s-milk, in blossom. It is a plant well known in Italy, but not 

 indigenous to France. Two years later the plants entirely disap- 

 peared. Similarly another growth, in another clearing of the forest, 

 was unearthed, and this in its turn flourished and disappeared. The 

 obvious botanical reason for the disappearance of a plant is that it 



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