4t 



size, next forms a series of bundles, and then secondary bundles or branches in 

 the valves, which ramify through the whole substance. 



In the case of C. Macleayana, and others, these bundles are more numerous, 

 and form a continuous line parallel to the inner surface and bounding the median 

 tissue of the sporophyll on that side, and through which substance, composed of 

 the irregular thin- walled cells originated from the pith, occasionally occur, however, 

 a few detached bundles. 



The chlorophyll parenchyma retains its character till the seeds have matured, 

 when the fundamental tissue having performed its functions, loses its vitality, 

 indurates into a granular, brownish-coloured ground mass with bundles, and 

 eventually atrophies. In a measure the whole period of the life history of the 

 cone corresponds to that of the stages of a Eticalyptus fruit, which in its early 

 growth is quite green (the calyx), and which eventually hardens into the fruit 

 capsule. 



The following are given to graphically illustrate the varying stages of the 

 different parts in this life history of a cone : — 



Figure 4 is a longitudinal section through the very earliest indications of 

 the formation of sporophylls, and when the leaves which go to form these organs 

 are not yet in the same plane as eventuates in a later stage of the cone's life history. 

 Figure 5 is a transverse section at the base of the cone in its earliest stages, the 

 outer portions being cut off ; the point desired to be illustrated is the attachment 

 of the sporophylls to the central axis which is surrounded in this case by a ring 

 of nine oil cavities, and which number is found later to increase on the inner side 

 of the cone valves. Portions of the six cone-valves can be traced. This plate is 

 likewise interesting as it shows the lysigenous origin of the oil cells or cavities on 

 what is later, the inner surface of the valve. Eventually oil cavities are formed 

 throughout the fundamental tissue, but more especially located near the outer 

 edge of each valve, and even in the case of C. robiista and C. verrucosa amongst 

 the epidermal cells. 



The occurrence of oil cavities in the cones is marked by two features^ 

 their numbers, and the chemical characters of the oil contents — and as regards 

 the latter, it is shown under C. rohusta and C. verrucosa that the oil of the cone 

 valves is optically, at least, distinct from that of the leaves. The cause of this 

 variance is a problem still to be settled by the physiologist ; but perhaps in the 

 formation of resin in the fruits one active form has been utilised more than the 

 other. The comparative abundance of oil cavities in the valves maybe a provision 

 of nature to provide protection to the maturing seeds by lessening or warding off 

 the power of the solar heat rays in dry-country species. Figure 6 is a 32-magni- 

 fication of a similar transverse section to Figure 5, but in this case the central axis 



