366 Mr Philip Sewell's Observations upon the 



The leaves of S. ceratophylla, which in many respects 

 closely resembled the above in the earliest stages of the 

 plant's development, although increasing very conspicuously 

 in length, also became relatively broader ; they change from 

 lanceolate to ovate, the petioles subsequently elongating so 

 as to free the lower earlier leaves from an overdue shading 

 by the coarser uppermost ones. The leaves of >S'. variegata 

 similarly pass through the same change, from an approxi- 

 mately spathulate to a more oblong-lanceolate shape, although 

 it does not possess petioles in its earliest leaves. 



A very distinct form of leaf, such as that of S. canariensis, 

 is in general outline much the same in all the youngest 

 leaves. It is some time before leaves are developed which 

 show an evidently hastate base, although this is a character- 

 istic feature of the leaves of the fully-developed plant. 



Similarly, the first leaves in S. hispanica and >S'. aurita are 

 more rotund than are the typical leaves ; it is not until the 

 third or fourth leaf that any indication is given of the 

 lyrate or lobed character of the leaves of the fully-developed 

 plant. 



The pinnate leaves of the mature plant in S. interrupta 

 are not produced in the pairs immediately succeeding the 

 cotyledons. In some seedlings the third or fourth leaf 

 showed a minute leaflet situate on the petiole at some little 

 distance from the terminal leaflet. Also, in a note taken of 

 this species on the 120th day, we have remarked that the 

 lamina of the first leaf of the plumule resembles the coty- 

 ledon in that it is abruptly united to its petiole ; the lamina 

 and petiole of succeeding leaves are less bluntly united. The 

 fifth and sixth leaves have each a pair of leaflets 6 mm. from 

 the terminal leaflet and 15 mm. across on the above date. 



Comparison may be made between the dimensions pre- 

 viously given of the leaves of S. interrupta and those taken 

 on the l75th day, when fourteen leaves had been developed. 

 The dimensions of the leaves of a mature plant are also 

 given : — 



175th day — Total length, . . 100 mm. ; lamina, 55 x 35. 

 „ Leaf from mature plant, 250 ,, lamina, 110 x 60. 



It is perhaps hardly worth while to notice in any detail 

 the changes in size to be observed between the leaves of an 



