e of the petals is frequently
accompanied by other changes of a similar nature in other parts of the
flower, and sometimes by the abortion of the sexual organs. Thus, in
_Actaea spicata_, as observed by Fresenius, the petals were replaced by
true petiolate, palminerved, lobed leaves, the stamens and pistils
being abortive. In _Ranunculus_ the leaves that appear in the place of
the petals have no scale at their base, and in _Tropaeolum_ the calyx (or
receptacle) is free from the usual spur.

The absolute frequency of this occurrence seems to be greatest in those
flowers which are normally polypetalous. The petals of these flowers, as
a general rule, are more like the leaf-sheaths than the leaf-blades as
to their venation, hence it would seem that the phyllomorphic condition
in these petals is a manifestation of a greater degree of organizing
force than that which occurs in those cases where the petals are
normally present in the form of contracted blades or laminae. (See the
remarks in the preceding section.)

Frondescence of the petals has been observed most frequently in the
following cases; some, perhaps, were cases merely of virescence, q. v.;
see also under Chloranthy, Prolification.

Ranunculus repens!
Delphinium Ajacis.
crassicaule.
Aquilegia vulgaris.
Actaea spicata.
*Brassica oleracea!
Diplotaxis muralis.
Hesperis matronalis.
Thlaspi bursa pastoris.
Sisymbrium tenuifolium.
Turritis glabra.
Raphanus sativus.
Peltaria alliacea.
Alyssum incanum.
Erysimum Barbarea.
officinale!
cheiranthoides.
Cheiranthus Cheiri.
*Dictamnus Fraxinella!
Lychnis sylvestris.
dioica!
Alsine media.
Cerastium vulgatum!
triviale.
Reseda lutea.
Phyteuma.
Malva sylvestris.
*Tropaeolum majus!
Geranium, sp.!
Triumfetta, sp.!
Epilobium hirsutum!
OEnothera striata.
Rubus, sp.
*Rosa, var. cult.!
*Trifolium repens!
Spiraea oblongifolia.
Amygdalus communis.
*Rosa!
Cerasus vulgaris!
Persica vulgaris!
Potentilla nepalensis.
Geum rivale.
Daucus Carota!
Heracleum Sphondylium.
Torilis Anthriscus.
Echinophora maritima.
Campanula rapunculoides.
glomerata.
Phyteuma spicatum.
Calendula officinalis.
Cirsium tricephalodes.
Senecio vulgaris.
Scabiosa columbaria.
agrestis.
Lonicera xylosteum.
Periclymenum.
Gentiana Amarella.
Gilia glomeriflora.
*Symphytum officinale.