566 
PHANEROGAMS. 
the number and position of which the number and position of the carpels might 
otherwise be more easily determined, we are thrown back on the direct observation 
of the first stages of development and on the numbers of the styles and stigmas. 
Failing this, the solution of the question depends on morphological relationships 
which are still by no means made out with sufficient certainty, notwithstanding the 
numerous researches which have been made on the development of the flower. 
Besides the number of the carpels which have coalesced to form the ovary, it 
is a question of interest whether in any particular case the ovules have been pro- 
duced laterally on the floral axis or as its terminal structure. In the cases of 
Piperacese, Polygonacese, Nai'as, Typha, &c., where only a single ovule springs from 
the base of the ovary, it is evident that this must be the terminal structure of 
the floral axis ; and the investigations of Hanstein and Schmitz, Magnus, Rohrbach, 
and Payer, have proved in addition that not only the ovule as a whole, but the 
nucellus itself, must be considered as a terminal structured It must not, however, 
be inferred from this that every ovule which springs from the base of the cavity of 
the ovary necessarily forms the apex of the floral axis ; for it is conceivable that the 
axis itself may have ceased to grow, but has produced an ovule at the side of its 
apex, a case which we shall meet with further on in the inferior ovary of Compositse. 
In a few cases the floral axis rises free within the spacious cavity of the ovary and 
produces ovules laterally, as occurs in Primulaceae (Fig. 392) and Amaranthaceae 
(in Celosia, according to Payer). 
The Inferior Ovary of epigynous flowers results from the retardation or com- 
plete suppression of the apical growth of the young floral axis, its peripheral tissue 
rising as an annular zone, and producing on its free margin the perianth, stamens, 
and carpels (Figs. 393, 394). The hollow structure which is thus formed, and 
which is at first open above, is afterwards covered over by the carpellary walls 
which close in above it ; the apex of the floral axis Hes at the bottom of the elongated 
cup-shaped or tubular cavity. Notwithstanding this striking displacement of the 
axial parts, the structure of the inferior ovary resembles that of the free polycarpellary 
ovary in almost all respects ; it may also be either unilocular or multilocular — if 
unilocular, the placentation may be basilar, lateral, or parietal. When the placentation 
is basilar, the ovule sometimes appears as if it were the terminal structure of the 
apex of the axis; as for instance the erect ovule of Juglandese. In Compositse, 
on the other hand, the position of the single anatropous ovule is not terminal 
but lateral ; the apex of the floral axis may often be clearly made out as a small 
elevation beside the funiculus, and in abnormal cases it undergoes further develop- 
ment into a leaf-bearing shoot ^. In Samolus the apex of the axis rises within the 
unilocular inferior ovary as in the superior ovary of other Primulaceae (Fig. 392), and 
bears a number of lateral ovules. If the placentae of the unilocular inferior ovary 
are parietal, they form on the wall two, three, four, five or more ridges from above 
downwards or from below upwards, and bear two or a larger number of rows of 
ovules (as in Opuntia or Orchidese). These placentae, which project more or less 
1 [See infra, p. 574.] 
^ Cramer, Bildungsabweichurigen und mofphologische Bedeutung des Pflanzen-Eies (Zürich 1864). 
— Köhne, Die ElUthenentwickelung der Compositen, Berlin 1869. — Buchenau, Bot. Zeit, 1832, 
No. 18 £■/ se^. 
