112 MR. G. BKNTHAM ON MYRTACE.i:. 



other, but there are Bumerous species where it is difficult to say 

 whether tlie caljx-tube is or is not to he characterized as produced 

 above the ovary. In capsular Myrtacese there are many genera 

 w^here this development of the tube above the ovary is constant, 

 or nearly so ; but I have never found it a safe character to rely 

 upon in species not showing other more essential ones. 



The degree of development of tlie entire portion of the caJyx- 

 limb, when the lobes do not reach the disk, is seldom of much im- 

 portance, although useful in aiding in the discrimination of Fsi- 

 dium and other genera of Eumyrtese, so very deficient in positive 

 characters. It always, however, requires careful attention ; for 

 where this part is much developed in the young bud, it is apt to 

 split before expanding, so as to give an erroneous idea of the aes- 

 tivation of the calyx-lobes. In all Myrtacese, except a few genera 

 of the anomalous tribe Lecytliide^e, and tlie still more anomalous 

 genus Foetidia, the aestivation of the real calyx-lobes is, as far as 

 I have observed, always imbricate, or at least not valvate ; and, 

 with the above exceptions, it forms an important element in the 

 separation of Myrtacese from Lythrarieae. In Fsldium and its 

 allies, as in some species of Bauhinia and allied Leguminosse, the 

 real imbricate lobes of the calyx are often so small as to elude 

 observation, or are quite abortive, and the entire part of the limb 

 bursts more or less regularly, so as to have caused the sestivation 

 to be erroneously described as valvate. In other genera the 

 lobes are also occasionally so small, and separated in the full- 

 grown bud by so wide a sinus, that it requires the examination of 

 a very young bud to detect their overlaj^ping. In some, however, 

 the valvate character has been attributed to them, even in the 

 works of distinguished botanists, from mere inadvertence. 



The form of the calyx-lobes, which we should a priori place low m 

 the scale of importance among generic characters, takes never- 

 theless a much higher degree in some Myrtacese. This is especially 

 the case in the tribe Chamselaucieae, where it is the most pro- 

 minent character of two of the most natural and largest genera, 

 Verticordia and Calythrix, prevailing over the usually more essential 

 ones derived from the anthers. 



There are a few Chamselauciese (two species of Darimniay Mi- 

 cromyrtus elohata, &c.) where the calyx-limb is so minute or even 

 entirely undeveloped, and the petals so apparently continuous with 

 the calyx-tube, that the perianth has been described as simple (one 

 of the causes of the non-recognition of the old genus Farwinia). 

 A careful search will, however, generally disclose either micro- 



