ANGIOSPERMS. 



497 



In a few cases the floral axis rises free within the spacious cavity of the ovary and 

 produces ovules laterally, ,as occurs in Primulaceee (Fig. 361) and Amaranthacese 

 (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. 362, 363). 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 lies at the bottom of the elongated 



Fig. 362.— /-/'// stnpes of dcvelopnunt of the flower of 

 Helian/hus autiuus: I calyx, c corolla, y filaments, a anthers, 

 X basal portion which afterwards developes into the lower 

 part of the tube of the corolla which bears the epipetalous 

 stamens, /A' the inferior ovary, SK the ovule, k carpel, 

 gr style. 



Fig. 363. — A-D stages of development of the flower of 

 Ccthi7ithe iie}-atri/olia (after Payer) : A and C seen from above, 

 B and D in lonj^itudinal section, s sepals, p petals, // the 

 petal which developes into the labellum, «/"the single fertile 

 anther, ae and ai abortive anthers of the outer and inner 

 whorl ; m B as are the sterile stamens, in D ep one of the 

 three carpels. 



cup-shaped or tubular cavity. Notwithstanding this striking displacement of the 

 axial i)arts, the structure of the inferior ovary resembles that of the free polycarpeflary 

 ovary in almost all respects; it may also be either unilocular or multilocular — if 

 unilocular, the placentation may be either basilar or lateral. 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 Compositae, 

 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 



^ Cramer, Bildungsabweichungen und niorphologische Bedeutung des Pflanzen-Eies (Zurich 1864). 

 — Kohne, Die Bliilhenentwickelung der Compositen, Berlin 1869. — Buchenau, Bol. Zeit. 1832, 

 No. iS el seq. 



K k 



