Mil. G. i3JiNTilAM Oy MYKTACK.K. 108 



1. Calyx. 



The modifications of the calyx in Myrtacese have been made 

 great use of by the multipliers of genera, and more or less passed 

 over by the consolidators. Tested by the degree of constancy in 

 groups otherwise natural, the form of the calyx-tube is but rarely 

 available even as a secondary character, whilst that of its limb or 

 lobes is the only one available for the limitation of some universally 

 admitted genera (e. g. Verticordia)^ or the one mainly relied upon 

 in others (e.g. Psidiuin). 



The marked distinction in Myrtacese and EosacCcTe between the 

 calyx-tube and its limb, /. e. the portion below and above the 

 edge of the staminal disk, is so great that many modern botanists, 

 especially Germans, deny that the former is a portion of the calyx 

 at all. They regard it rather as an expansion of the peduncle, 

 or as a separate organ, which they call hypantliium^ and limit the 

 calyx to the portion above the disk. This they describe in Myr- 

 tacese as consisting of distinct sepals, or more rarely as a gamo- 

 sepalous, lobed, toothed, or truncate limb, or as altogether defi- 

 cient. Those on the other hand who follow the French doctrine 

 o^ soiidures or concretion of organs, give the name of calijx to the 

 whole of the external layer of floral covering, from the base of the 

 ovary, whether consolidated with the ovary into a single mass or 

 more or less separable from it, designating as calyx-tuhe the hyp- 

 anthiura of the Grermans, whether adnate to the ovary or free ; 

 the calyx-lobes or segments of the limb correspond to the German 

 sepals, and the toothed or lobed limb to their toothed or lobcd 

 calyx. The settling these differences docs not now depend so much 

 upon the observation of facts, which are very generally and accu- 

 rately known, but upon the most logical, or even the most con- 

 venient mode of interpreting those facts ; and our conclusions 

 must be drawn, not from the modifications presented to us in 

 Myrtaceae and Rosacea? alone, but from what we observe also in 

 other allied orders, and from the general principles forming the 

 theory of concretion and distinction of organs ; and I trust I may 

 be excused in recalling here some of the axioms, however simple 

 and generally admitted, upon which that theory is founded, as it 

 appears to me that w^e are often too ready to lose sight of them 

 m the description of special points. 



1. Throughout biology, the organs of a living being are not 

 parts separately formed or superadded to each otlier, as wlien we 

 ^uild a house or construct a machine ; but every organ, as every 



