785 



also differ by being sometimes bilabiate; whilst the disk itself is 

 greatly contracted and reduced, and its tubular florets appear to have 

 become very small and abortive ; thus apparently indicating that the 

 florets of the radius have become lengthened and enlarged at the ex- 

 pense of those of the disk." Mr. Hogg adds, that in general appear- 

 ance these large double flowers of Matricaria Chamomilla resemble 

 the common white double flowers of the genus Chrysanthemum. 



Observations on certain Species of the Natural Order Oycadece, by 

 James Yates, Esq., F.R.S., F.L.S., &c. 



Cycas revoluta. Since the year 1799, when a female plant of this 

 species flowered at Farnham, as described by Sir James Edward 

 Smith in the 6th volume of the Linnean Transactions, a considerable 

 number of the same sex have flowered in this country. Five indivi- 

 duals might be mentioned, which are now in a flowering state. On 

 the other hand, only one male plant is known to have flowered in our 

 island. This was formerly at York, and is now in the Botanic Gar- 

 den at Sheffield. Its cone, or rather spike, nearly a metre in length, 

 is preserved in the museum of the Yorkshire Philosophical Society, 

 and exhibits in a very striking manner the affinity of this genus to the 

 rest of the Cycadeae, whilst the female cone of Cycas differs greatly 

 from that of all the other genera. 



Macrozamia spiralis. The genus Macrozamia, the scales of whose 

 cone, whether male or female, are distinguished by terminating in a 

 single spine, directed upwards, appears to be very closely allied to 

 the Dioon of Professor Lindley. It is difficult to distinguish the 

 young seedlings of these two genera. The only perceptible difference 

 is, that in Macrozamia the leaflets are contracted at the base, and are 

 more remote from one another than in Dioon. Also in both of these 

 genera the leaves of the young plants differ most remarkably from 

 those of the same plants in the adult state. Macrozamia, as well as 

 Dioon, approaches Cycas in the circumstance that the leaflets are de- 

 current, whereas in the remaining genera, Encephalartus, Zamia and 

 Ceratozamia, they are not at all decurrent, but are contracted at the 

 base, and join the midrib of the leaf by a distinct articulation. The 

 decurrent leaflets of Macrozamia spiralis are especially apparent in 

 the young plants. 



Encephalartus brachyphyllus. A male plant flowered last year at 

 Chatsworth. The cone appeared early in May, and was full-grown 

 in two months. 



Vol. hi. 5 i 



