Fie aria verna, and other Members of the Ranunculaceae . 77 
Such increase has resulted in mechanical pressure, which in turn has pro- 
duced displacement, so that a high phyllotaxy has resulted. Perhaps, too, 
shortening of the torus has contributed to this effect. As already pointed 
out, this interpretation harmonizes with the fact that trimerous flowers are 
frequent amongst the Ranales as a whole and particularly associated with 
the less specialized and arboreal forms. 
The view here put forward is, then, that the primitive Ranunculaceous 
flower exhibited an androecium and gynaeceum of members either arranged 
in alternating whorls of three members each or on six orthostichies and 
probably borne on an elongated axis. The essential organs were surrounded 
by a perianth of foliar origin also consisting of trimerous whorls. From this 
condition both the pentamerous calyx of Ranunculus and tetramerous calyx 
of Clematis have been derived, whilst the more primitive perianth of two 
trimerous whorls is seen in Eranthis and Anemone spp. What was perhaps 
the early Ranunculaceous type is seen in some species of Magnolia in which 
the whole floral structure is composed of alternating trimerous whorls. 
As a subsequent specialization the outermost stamens have in some 
cases developed as an attractive whorl (e. g. Ranunculus , &c.), but in others 
foliar perianth members are alone present and perform both functions of 
protection and attraction (e. g. Anemone pulsatilla ). 
The occurrence of trimery and androecial fission as a feature of the 
Ranunculaceae is all the more interesting as both are found in the Alisma- 
ceae, to which Monocotyledonous family the Ranunculaceae exhibit so 
many resemblances* 
VIII. Summary. 
The variations, both meristic and substantive, in the flowers of Eranthis 
hy emails , Ficaria verna , and other members of the Ranunculaceae, are 
described and the following facts established : 
(1) Meristic variation is exhibited in all the floral regions, involving a 
corresponding variation in the total number of parts present. 
(2) There is usually an obvious correlation between the variation in 
the different parts of the flower, and, in general, increase or decrease is 
exhibited simultaneously by the perianth, androecium, and gynaeceum. 
(3) Branched: stamens are not infrequently present, and bifurcated 
petals have been observed in several members of the group. Branched 
carpels are recorded for Helleborus . 
(4) The position of the supernumerary perianth segments is consistent 
with their origin by fission. 
(5) The two-whorled trimerous perianth of Eranthis , Anemone , &c., is 
sometimes replaced by a pentamerous whorl exhibiting the quincuncial 
arrangement, a change that can be attributed to fusion between one member 
of the outer whorl with one of the inner. 
