The Origin of the Perianth of Flowers 43 
Now we must look for the nearest origin of our modern flower 
to the cone of the Cycadaceae, which is, in fact, the primeval flower’ 
consisting of a much-elongated axis clothed with very numerous 
spirally-arranged sporophylls. But the chief point of interest lies 
in the fact that in all cases a few of the lowermost sporophylls are 
perfectly sterile and somewhat altered in shape, although not in 
texture or colour, from the fertile ones. They may, in fact, be 
regarded as the progenitors of the perianth-leaves of the Angio- 
sperms. And it is obvious that they have been derived by simple 
sterilisation of the lowermost sporophylls of the cone. (Big. 1). .. 
We may, in tracing from this point onwards, the evolution of 
the flower, confine our attention almost exclusively to the order 
Ranunculacete among the higher plants, as there is a great deal of 
nstruction to be gleaned from this group. Here we find some of 
the primitive characters of the cone still present: e.g. inconstancy 
and indefiniteness in the number of members of the various 
categories of floral foliar organs (not yet stereotyped into the 5’s or 
4’s or 3’s of the more advanced orders); the much-elongated floral 
axis, as seen especially in Myosurns (Fig. 2) and also in an allied 
order, the Magnoliaceae. The new, more advanced characters which 
have appeared are:—the coloration of the perianth (yet exceptions to 
this occur), and the frequent addition of an extra category or whorl 
of perianth-leaves to that already present. Having recognised these 
features we will first of all enquire into the origin of the corolla. 
Niigeli 1 and subsequently Drude 2 were the first to point out the 
probable origin of the corolla frojm the outermost whorl of stamens. 
Not long afterwards Grant Allen 2 ingeniously endeavoured to prove 
that the petals of flowers are in all cases derived from stamens. 
With the last-named authors he considers the calyx to have been 
derived from bracts. The great German botanist Prantl 4 held, on 
the other hand, that the corolla, like the calyx, arose from the meta¬ 
morphosis of bracts, and that staminodial structures only (including 
nectaries and small petaloid organs bearing incomplete or rudi¬ 
mentary anthers) bad been transformed from the outermost stamens. 
Having especial regard to the'Ranunculaceae, he always drew a 
sharp distinction between these staminodes on the one hand and the 
corolla on the other. For instance, he regards the nectar-bearing 
“petals” of Ranunculus as staminodes and possessing a totally 
1 Meclianisch-pliysiologisclie Theorie der Abstawinungslehre; 
p. 496 1884. 
2 '*I)ie systematisclie and geographische Auorduiiiig der 
Phaiieroganieii ; ” Schenk’s Haridbuch, Vol III., part 2, 1887. 
3 The Colours of Flowers, 1882. 
4 “Beitrage zur Morphologie and Systematik der Kauuncu- 
laceae; ” Kngler’s Bot. Jabrbiicher, Vol. IX., 1887, 
