8 THE AUSTRALIAN NATURALIST. 
STUDIES IN FOLIAR PERIODICITY. 
By Epwin CuHEEL. 
The monthly excursions held on July 9th and August 6th 
respectively, were conducted for the purpose of studying the 
leaf-fall and foliar renewal of certain native as well as some 
exotic shrubs and trees in the Outer Domain and Botanic Gar-- 
dens, and Hyde and Cook Parks. This matter has engaged the 
attention of the writer of these notes since 1916, when it was 
noticed that an English Oak Tree (Quercus robur var pedun- 
culata) in the Outer Domain, quite near the main entrance to 
the Botanic Gardens, Sydney, had. commenced to unfold or re- 
new its leaves on the 28th of August, whilst other trees of the 
same species showed no signs of leaf renewal. 
In following the matter up more closely, a group of eight 
trees of the same species were observed growing equal dis- 
tances apart, along the foot-path in Hyde Park, from St. 
Mary’s Cathedral to Market Street. Although the individual 
trees belong to the same species, and are in an open position, 
receiving light from all directions, that is to say there are no 
trees surrounding them to rob them of light, it is very notice- 
able that the leafbuds of the second tree on northern side of 
the path commence to expand fully a month earlier than the 
other individuals of the same species. 
In the Outer Domain there are four trees of Ficus infec- 
toria (I°. Cunninghamii of Australian Botanists). which became 
completely defoliated once a year. The leafless stage lasts 
_ only about a month, namely in July, when foliar renewal be- 
gins again early in August. The large tree of the latter species 
near the main entrance to the Botanic Gardens (not far from 
the Art Gallery) is slightly in advance of the other trees of 
the same species, as the buds on the tips of the branches or 
branchlets are distinctly green on the 6th of August, whereas 
those of the other trees are not visible until a week or so later. 
Early in September the leaf-buds are sufficiently advanced to 
give the whole tree a distinctly green appearance, and when 
studied in conjunction with the two individual trees of Oaks 
previously referred to, they may be taken as the harbingers of 
‘Spring in the Parks and Domains of Sydney. 
Another species of Australian tree worthy of special note 
in connection with the question of foliar periodicity is Ficus 
Henneana. The trees of this species commence to become de- 
foliated about August 10th, and although they are not so 
markedly deciduous as those of I’. infectoria, it is particularly 
interesting to note how rapidly the apparently fresh shiny 
