&R0S8 ANATOMY Of FLOWERING PLANTS. XXXV 



rounded by the tubular sheath composed of adnate calyx, corolla, 

 and androecium. In some nearly related cases, in addition to the 

 structures described above as perigynous, there is a complete 

 fusion of the calyx, corolla, and stamen bearing tube -with the 

 gynoecium, so that the ovule-bearing portion of the latter is 

 below the rest of the flower. The perianth and the stamens are 

 said to be epigynous in such flowers, and the ovary is inferior. 

 (Fig. XXXy.) Some cases of epigyny are doubtless to be re- 

 garded as due to the adnation of the calyx, corolla, stamens, and 

 ovaries ; in others the ovaries are adnate to the hollow axis which 



Fio. XXX. V 1.— Heterostyled flowers of Primrose, showing the long-styled form 

 in the left-hand figure, and the short-styled form in the figure on the right 

 (From Darwin.) 



bears the perianth and stamens; in still others it seems probable 

 that the hollow axis is itself ovule-bearing, and that the true 

 carpels are borne on its summit. 



Certain terms descriptive of relations between the stamens and 

 pistils which have recently come into use require explanation here. 



Relative Ternns. — In many flowers the stamens and pistils da 

 not mature at the same time — such are said to be dichogamous ; 

 when the stamens mature before the pistils the flower is proter- 

 and/roiu; and when the pistils mature before the stamens they are 



