417 



Deciduous Leaves. 



It is unusual for a Eucalypt to be deciduous, and it is only the case with some 

 tropical species, e.g., E. alba (platyphylla) which at Kuranda, Northern Queensland, 

 loses its leaves pretty regularly during October and February. 



E. Houseana (W.V.F.) Maiden (see Part L, p. 293) of North-western Australia, is 

 also deciduous in some seasons. The matter of deciduousness in Eucalyptus might 

 well attract the consideration of a resident in tropical Australia. 



A number of Australian trees become deciduous as colder regions are reached, 

 but this does not apply to Eucalypts, so far as I have observed. But quite a number 

 of trees become deciduous on the approach of a local drought, e.g., in summer (about 

 February), Ficus Cunninghamii, in the Sydney district. 



The connection between the fall of the leaf and the commencement of the cold 

 period in the case of what are known as " deciduous " trees par excellence is simply 

 explained in the ordinary botanical text-books. 



Heat and cold are only the indirect causes ; the primary cause of the fall of the 

 leaf is the danger threatened to the plant by the continuance of transpiration when 

 either heat or cold is excessive. The throwing off of the transpiring surfaces becomes 

 necessary when the drought commences. In tropical and sub-tropical regions, where 

 no showers occur for comparatively long periods, the trees lose their leaves, and do not 

 produce fresh ones until the rain comes. 



Explanation of Plates (232-235). 



PLATE 232. 



E. agglomerata Maiden. 

 la. Juvenile leaves; 16, fruits. Hill Top, Southern Line, N.S.W. (J.H.M.) (See also figs. 6a and 66, 



Plate 38, Part VIII, then looked upon as intermediate between E. capitellata and E. eugenioides). 

 2a. Juvenile leaves: 26, intermediate leaf; 2c, mature leaf; 2d, umbel of buds; 2e, buds and flowers; 



2/, front and back view of anther. Near Jerrimbool Railway Station, 3J miles from Hill Top, 



on main southern road (J. L. Boorman). 



E. Simmondsii n.sp. 

 3a. Juvenile leaves, with bases slightly stem-clasping; 36, juvenile leaves a stage further advanced, and 

 still in an almost horizontal position ; 3c, juvenile leaves in an almost vertical position ; 3d, mature 

 leaf with hooked apex (with flower buds) ; 3e, mature leaf. Note that 3e is in a more advanced 

 stage than 3d; it is smaller, and the venation less conspicuous. 3/, buds as mature as I have 

 seen them; 3g, anther; 3h, fruits. Smithton, beyond Burnie, Tasmania (Rev. J. H. Sirnmonds). 

 The Tvpe. 



PLATE 233. 



E. sepulcralis F.v.M. 

 la. Pendulous branchlet of mature leaves; 16, buds; lc, front and back views of anther; Id, nearly ripe 

 fruits ; \c, fruits as ripe as I have seen them. Eyre's Range, 10 miles north of Hopetoun, South 

 Coast of Western Australia (R. K. Wellstead). 



E. torguata Luehmann. 

 2a, 26. Juvenile leaves; 2c, intermediate leaf; from near Coolgardie, W.A., by District Forest Banger 

 J. M. Cusack. 3a, mature leaf ; 36, mature leaf and one flower. Note that the calyx tube shows 

 a little less ribbing than as figured at fig. 6, Plate 13, Part IV. Note also the style obtruded 

 before the stamens have their filaments unbent. This species has a long operculum, as will be 

 seen on reference to the figure quoted. 



