MR. G. BEXTHAM ON MTRTACE^. Il7* 



is the general cliaracter of the Order ; but there are a few ex- 

 ceptions, and, as iu some other Orders, such as Riibiaceae, Cani- 

 panulacese, &c., where this character is important from its all but 

 universality, these few exceptions are specific only, not generic. 

 It IS as impossible to found definite groups on the greater or less 

 degree of adherence of the ovary in ScecJcea, Uypocalf/mma^ Lep- 

 tospermum^ Melaleuca^ Beaufortiay Calotliammis^ Tristania^ Cloezia^ 

 Jiletrosideros^ ISlantliostemon^ Coiiroiipita or Lecytliis^ as it is in 



Hedyotis or Lobelia. 



The number of parts or carpels of the gynaecium was in former 

 days considered of much importance in the distinction of genera, 

 and, although now found to be often very variable, in Myi^tacese is 

 still occasionally available for that purpose. There are, for in- 

 stance, large genera (such ^% JSIyrtus, Myrcia^ and Eugenia) where 

 the number is, with very few exceptions, two or three, and others 

 (such as Campomanesia, Psidiiim, Calycolpus, Decaspermum, &c.) 

 where that number is very rarely below four or five ; and the whole 

 tribe of Chamaelauciea? is still more constantly circumscribed by 

 the monocarpellary gynsecium : but even this is not quite definite ; 

 there is a passage from Thryptomcne to ScJioIfzia, which makes it 

 sometimes uncertain whether we have one 2-ovuIate, or two 1- 



ovulate carpels. 



The modifications of the style are few, relating chiefly to its 

 length and the degree of dilatation of the stigma, and are specific 

 only, or scarcely even so much. 



There is very frequently a thickening of the disk within its 

 stamen-bearing margin round the base of the style. In some 

 Barringtoniere it forms a prominent ring, or short cup, about lialf- 

 way between the staminal margin and the central style ; more 

 frequently it is thick at the stamiual margin, and gradually atte- 

 nuate to the centre, making a concave summit to the ovary ; or, in 

 a great many Leptospermere, it is thick all over, and pnlvinate, 

 leaving only a very narrow tubular cavity round the style. In 

 several of those species of Qdyfhrix and Bcecl^ea in Avhich the calyx- 

 tube, lined by the thin disk, is produced far above the ovary, and 

 the staminal margin is thickened round the style, this thickened 

 margin has been mistaken for the summit of the ovary, which has 

 been described as not completely closed, but pierced through for 

 the passage of the free style. This, for instance, was one the chief 

 characters on which the genus Babingtonia was founded. A care- 

 ful examination, however, of species has persuaded me that these 

 modifications of the epigynous disk in Myrtaeea?, as in Umbel- 



