_Linaria vulgaris_ Roeper observed a calyx consisting of a double
series, each of five sepals, in conjunction with other changes.[431] It
is also common in double columbines, delphiniums, nigellas, &c.

In the 'Revue Horticole,' 1867, p. 71, fig. 9, is described and figured
by M. B. Verlot a curious variety of vine grown for years in the Botanic
Garden at Grenoble, under the name of the double-flowered vine. The
place of the flower is occupied by a large number of successive whorls
of sepals disposed in regular order, and without any trace of the other
portions of the flower. It is, in fact, more like a leaf-bud than a
flower. The outermost whorls of this flower open at the time when the
ordinary flowers of vines do; the second series are gradually produced,
and expand about the time when the ovaries of the normal flowers begin
to swell; a third series then gradually forms, and so on, until frost
puts a stop to the growth. This malformation, it appears, is produced
annually in certain varieties of vine, and may be perpetuated by
cuttings.

The flower of the St. Valery apple, already alluded to under the head of
sepalody, might equally well be placed here. It is not very material
whether the second whorl of organs be regarded as a repetition of the
calyx or as a row of petals in the guise of sepals.

Engelmann[432] cites the following plants as occasionally presenting a
repetition of the calyx, in most cases with a suppression of the other
floral whorls:--_Stachys lanata_, _Myosotis palustris_, _Veronica
media_, _Aquilegia vulgaris_, _Nigella damascena_, _Campanula
rapunculoides_.

=Pleiotaxy in the perianth.=--Increase in the number of whorls in the
perianth is common in lilies, narcissus, hyacinths, &c. It may be also
met with occasionally among orchids. The lily of the valley
(_Convallaria maialis_) seems also to be particularly subject to an
increase in the number of parts of which its perianth consists, the
augmentation being due partly to repetition or pleiotaxy, partly to the
substitution of petaloid segments for stamens and pistils.[433]

In this place may also be mentioned the curious deviation from the
ordinary structure occasionally met with in _Lilium candidum_, and known
in English gardens as the double white lily. In this case there are no
true flowers, but a large number of petal-like segments disposed in an
irregular spiral manner at the extremity of the stem, some of the
uppermost being occasionall