DISPLACEMENT. 95 
occupies the place of a suppressed or abortive organ, 
but frequently assumes its colour, and, to some extent, 
its function. ‘This has been alluded to in the case of 
the leaf of Gesnera (see p. 88) and in Orchids this 
replacement seems to be very common; thus, in 
addition to the cases before mentioned, in a flower 
of an Odontoglossum, for which | am imdebted to 
Professor Oliver, the two lateral sepals were united 
together and occupied the position of the labellum, 
which was absent. A similar occurrence happens 
occasionally in Lycaste Skinneri, thus recalling the 
structure of Masdevallia, where the labellum is normally 
very small. ‘The arrangement in Lycaste may thus 
be symbolised : 
the + indicating the position of the absent labellum. 
Cases of this kind are the more interesting from 
their relation to the fertilization of these flowers by 
insects ; 1t seems as though, when the labellum, which 
performs so important an office in attracting and guid- 
ing insects, 1s deficient, its place is suppled by other 
means. 
Displacement of the parts of the flower from elon- 
gation of the receptacle is a not infrequent teratological 
occurrence, resulting sometimes in the conversion of 
the verticillate into the spiral arrangement. Instances 
of this are cited under Elongation, Prolification, &c. 
In this place it is merely necessary to refer to a curious 
circumstance that is met with in some double flowers, 
owing to this separation of some parts of the flower 
and the cohesion or adhesion of others. Thus, in 
some double flowers of Primula sinensis and in the 
Pea (Piswin sativum), I have seen a gradual passage of 
sepals to petals, so that the calyx and corolla formed 
one continuous sheet, winding spirally around the 
