MR. a. BENTHAM ON MmXACE^^ 113 



scopic teeth alternating witli the petals, or a slightly prominent 

 annular ring. In some species of Eugenia .(sect. Syzyginm) and 

 a few other Myrtese, where the calyx-limb is reduced to a trun- 

 cate line, the difference of consistence readily separates the corolla 

 from the calyx-tube. This character, however, never appears to 

 be of more than specific value. 



The consolidation of the calyx-lobes into a calyptra or oper- 

 culum, circumsciss at the base, and falling off in a mass, as in Cahjp- 

 tranthtcs and Acicalyptus^ proves to be a better generic character 

 than a similar consolidation of the petals, which in Eugeniax^ but 

 a vague sectional distinction, and often not constant in species. 

 The peculiarities of the operculum of Eticalyptus, whether calycine 

 or corolline, will be better reserved for the special observations on 

 that genus. 



A duplication of the number of calyx-lobes occurs in some species 

 of Yerticordiay in Pileantlius, and in Oshornia. In the former 

 case, the accessory lobes, different from the normal ones, are evi- 

 dently a prolongation of the joint nerve produced by the union 

 of the two lateral nerves of two adjoining sepals, as in many 

 Lythrariese, Labiata?, &c., and are in this instance of no generic 

 value. In the other two genera the 10 or 8 lobes are all precisely 

 alike in shape, size, and position, and yet the alternate ones ought 

 perhaps to be regarded as accessory. In Osbornia, the petals 

 being deficient, we might have supposed that one half of the ap- 

 parent calyx-lobes were in fact petals ; but there is nothing in aesti- 

 vation, position, or ap2)earance to justify such an hypothesis ; and 

 in Pileanthus the normal number of petals and stamens are present 

 notwithstanding the duplication of the calyx-lobes, 



2. Corolla, 



The petals supply very few good generic characters. They are 

 sometimes wanting; but this is usually in exceptional species or 

 in monotypic genera. They are always imbricate in sestivatiou, 

 and often very much so, the external one completely enclosing the 

 others in the bud. Their form is often much varied, especially 

 in Verticordia ; but the differences are not even sectional. In 

 general in the Order they are broad, contracted at the base, or 

 very sliortly unguiculate, without the long claws and crumpled 

 laminae of most Lythrariese. In a fcAV species of Darioinia and 

 some other Chamaelauciese, where the calyx-lobes are much reduced 

 or obsolete, the petals are attached by a broad base, and in the 

 hud appear to be continuous with the calyx-tube ; and this charac- 



LINN. PBOG, — BOTA]!fY, TOL. X. I 



