94 MORPHOLOGY, OR COMPARATIVE ANATOMY. 



ever, that the term hermaphrodite is used in its morphological, not 

 in its physiological significance, for many flowers hermaphrodite 

 in structure are practically unisexual in function. In many plants 

 one of the circles of essential organs is suppressed, so that a given 

 flower has only stamens or only pistils ; such flowers are termed 

 unisexual or diclinous. The unisexual flowers are called respec- 

 tively staminiferous or male ( tf ), and pistilliferous or female ( $ ). 

 When flowers of both kinds occur on the same plant, this is called 

 monoecious (Oak, Birch, Vegetable Marrow, &c.) ; when they are 

 on distinct individuals, the plant is termed dioecious (Hop, Willow, 

 Bryony, &c.) ; when, as in some cases, the imperfection results 

 from a kind of regular abortion rather than total suppression, and 

 the same plant or species exhibits at once staminate, pistillate, and 

 hermaphrodite flowers, it is termed polygamous (Parietaria, many 

 Palms, Maples, &c.). Some plants bear neuter flowers, desti- 

 tute of both stamens and pistils : such is the case naturally with 

 the outer florets of many Composites, and it is constantly seen in 

 the garden Snowball ( Viburnum Opulus) and Hydrangea. 



The diclinous or unisexual condition is often typical and hereditary in 

 certain families, such as Amentiferae, &c. ; but cases of diclinism occur 

 not unfrequently in exceptional genera of families the majority of whose 

 genera are bisexual, as in Ruscus among the Liliaceae ; or in exceptional 

 species (by abortion), as in Lychnis dioica ; sometimes it occurs by abor- 

 tion in species normally possessed of perfect flowers, as in Asparagus. 



Arrangement of Parts. The suppression of an entire circle 

 renders a flower unsymmetrical ; for when the corolla is absent, 

 we find the stamens commonly superposed to the segments of 

 the preceding circle, as in Clienopodium ; but this is in accord- 

 ance with the normal type, as the stamens should be superposed 

 to the sepals, the intermediate petals (here suppressed) alter- 

 nating with both. Not unfrequently we find abortive organs, 

 such as sterile filaments or " glands," of various kinds forming 

 circles which restore the symmetry of apparently unsymmetrical 

 flowers. 



The cases of unsymmetrical conditions arising from the superposition of 

 the organs of succeeding whorls are explained by some entirely by suppres- 

 sion or abortion ; others more correctly refer some of these cases to chorisis. 

 In Geranium we find alternating with the petals five little glands which 

 must be regarded as abortive stamens, since in the succeeding whorl the 

 five stamens alternate with these and stand in front of the petals ; the 

 five innermost and longer stamens, again, are superposed to the glands. 

 In Erodium the outermost row is represented by glands, the second row 

 by sterile filaments, and only five perfect stamens exist. Much the same 

 conditions occur in the Linaceae. On the ground of such facts as these, 



