340 
Arthur W. Hill. 
the root-cap with mucilaginous walls ( c ), the layer of mucilage (ni) secreted by 
the tissue (s). x405 diam. 
Fig. 2. Transverse section through the tip of a root, showing root-cap ( c), 
the mucilaginous layer (rn) between the secretory layer and the cap, and 
the secretory cells themselves with distinct nuclei. x405 diam. Brushed 
and microtomed. 
Fig. 3. Transverse section above the root-cap. Note the wide layer of 
mucilage with faint radiating and tangential striations. The secretory layer 
(s), the exodermis ( e ) and the inner cortex. Root-tip brushed and microtomed. 
X 405 diam. 
Fig. 4. A few secretory cells more highly magnified. Shows the 
mucilage layer partially freed from the outer cell walls, the dense contents 
of the secretory cells and distinct nuclei. Treated with hydrofluoric acid and 
microtomed. X 1000 diam. 
Fig. 5. Longitudinal section in region of gradual modification of secretory 
cells into cells of the piliferous layer. Grains of sand still adhering. x405. 
Fig. 6. Portion of outer cortex soaked and teased out from herbarium 
material. Quite mature root showing the long root-hairs, with a single sand 
grain in situ, x 102 diam. 
Fig. 7. Lygeum Spartum. Transverse section showing portion of outer 
cortex of root in its thick part. The piliferous layer with root-hairs of normal 
type and the strongly cuticularised exodermis. x405 diam. Treated with 
hydrofluoric acid. 
CONIFERS DAMAGED BY SQUIRRELS. 
By Arthur W. Hill 
(Assistant Director of the Royal Botanic Gardens, Kew). 
[With Plate VII]. 
1HE damage which may be done to trees by squirrels is well 
shown by some interesting specimens of Thuya plicata, D. 
Don, and Cupressus Lawsoniana, A. Murr., sent to the Royal 
Botanic Gardens, Kew, by Mr. R. B. Rogers of Hexworthy, 
Launceston, Cornwall, for the Museum of British Forestry. 
The specimen of the Thuya, a photograph of which is re¬ 
produced in the accompanying Plate VII, came from a plantation 
at Treburtle, near Launceston, where the Cupressus was also 
growing. A large number of these trees have been placed in a mixed 
plantation of oak, beech, hornbeam, larch and Scots pine during 
the last twenty years, but the squirrels have attacked only the 
Thuya and Cupressus. The injured trees are from 12 to 14 feet 
high, and the damage was done at least two years ago according 
to Mr. Rogers’ account, which is fully confirmed by the condition 
of the specimens presented to Kew. 
