ORGANS OF EEPEODUCTION. 



233 



are iinisexual, both staminate and pistillate 

 flowers may be borne upon the same plant, as 

 in the Hazel, Oak, Cuckow-pint ( j?^. 377), and 

 the species of Carex, in which case the plant 

 is stated to be mo7icecious ; or upon different 

 plants of the same species, as in Salix {figs. 

 389 and 390), and Hemp, when it is dioecious. 

 In some cases, as in many Palms and Pellitory 

 (Parietaria), both staminate, pistillate, and 

 hermaphrodite flowers, are situated upon the 

 same individual, in which case the plant is 

 called polygamous. 



Like the sepals and petals, the stamens and 

 carpels are considered as homologous with 

 leaves, but they generally present much less 

 resemblance to these organs than the floral 

 envelopes. Their true nature is shown, how- 

 ever, by their occasional conversion into leaves, 

 and by other circumstances which will be 

 described hereafter when treating of the 

 Greneral Morphology of the Flower. 



1. THE ANDRCECIUM. 



Fig. 486. -Unisexual 

 staminate flower of 

 a species of Carex. 

 Tbe filaments are 

 long and capillary, 

 and the anthers 

 pendulous and In- 

 nate. 



The organs of 



The andrcecium is the whorl or whorls of 

 organs situated between the corolla on the 

 outside and the gyncecium on the inside {figs. 

 419 and 420), and it is so called because it 

 forms the male system of Flowering Plants 

 which it is composed are termed Stamens. Each stamen consists 

 generally of a thread-like portion or stalk, called the filament {fig. 

 421,/), which is analogous to the petiole of the leaf, and of a 

 little bag or case, a, which is the .representative of the blade, 

 called the anther, and which contains a powdery 

 matter termed the pollen, p. The only essential 

 part of the stamen is the anther with its 

 contained pollen ; when the pollen is absent, 

 as the stamen cannot then perform its special 

 functions, it is said to be abortive or sterile 

 {fig. 503, Is) ; in other cases it is termed /^'r^eVe. 

 When the filament is absent (which is but rarely 

 the case), as in the Cuckow-pint {fig. 487), 

 the anther is described as sessile. 



1 . The Felament. — In its structure the fila- 

 ment consists, 1st, of a central usually un- 

 branched bundle of spiral vessels terminating 

 at the connective of the anther ; and 2nd, of 

 parenchymatous tissue which surrounds the central bundle of 



^Kj. 48". Stamen 

 of the Cuckow- 

 pint {Arum macu- 

 latum), consisting 

 simply of an an- 

 ther sessile upon 

 the thalamus. 



