114 MB. G. "BEKTHAM ON MYRTACE^. 



ter becomes a constant generic one in AngopJiora and Eucalyptus. 

 Sometimes they are so coherent in the hud as to fall off at the 

 time of flowering in a single mass instead of expanding. A large 

 group of Old- World Eugenia^ has often on this account been gene- 

 rically distinguished ; but so many species have shown a gradual 

 passage from a tardy or uncertain separation to a permanent co- 

 ] lesion, that most botanists have now given up Syzygmm as a 

 genus. In Eucalyptus the consolidati(m is so absolute that it is 

 only by analogy with Angophora that we infer the origin of the 

 operculum. 



3. Andececium. 



The stamens, as in some other large Orders^ supply, in some 

 cases, many of the best generic characters, whilst in others the 

 same modifications can only be taken as specific or, at most, 

 sectional. 



Their insertion is always close to that of the petals, the disk, 

 whether thin and lining the calyx-tube or more or less thickened, 

 being always developed between the stamens and gynsccium, not 

 between the stamens and petals as in most Lythrariese, where, m 

 other words, the stamens are usually inserted on the calyx-tube 

 much below the petals. Where the stamens in Myrtaceae are in 

 one or two rows, they are on the margin of the disk ; where there 

 are many rows, they cover the surface of the disk in a ring spread- 

 ing from the margin more or less towards the centre, but always 

 leaving a clear space in the centre round the style, this clear space 

 being thin or thick, concave or convex, or projecting in a ring at 

 some distance from or close round the style. Sometimes the 

 margin of the staminal disk, or united portion of the androecium, 

 projects beyond the insertion of the petals in the form of a single 

 ring or short tube, or of a one-sided appendage, or of five reguJar 

 appendages alternating with or opposite to the petals, bearing the 

 filaments on their margin or inner face — always quitting the calyx- 

 tube at the same point as the petals, which remain free from the 

 projection, or, when it is annular, are more or less adnate to it 

 at the base. AVithout always supplying positive generic charac- 

 ters, these modifications are most of them very useful. The an- 

 nular union of the base of the stamens is general in most Eucha- 

 ma?lauciea?, it is one of the chief characters oi HgpocaJymma^ and 

 occurs here and there in other Leptosperme^, as well as in some 

 Barringtoniea?, without being of much more than specific impor- 

 tance. The projection of the margin of the staminal disk into a 



