GENERAL NATURE OF THE FLOWER. 



11 



eases being thus masked. In many cases 

 an appendage apparently consisting of a 

 modified stipule esists. 



Of the Pistil — Thestenvlilxe base(Fi^. 



9 a), not present in most flowers, is the 

 Stipe or Thecaphore. It represents the 

 united petioles of the sporophylls. The 

 body of the pistil represents either a sin- 

 gle sporophyll having its edges brought 

 together and united with the upper leaf- 

 surface inside of the cavity, or, as in this 

 case, more than one sporophyll with the 

 edges of one meeting those of the other 

 in the same manner, or in many cases in 



a different manner. The edges along the 

 hollow portion, after meeting, project 

 inward more or less. Elsewhere, for a 

 greater or less distance, they may be 

 everted. A sporophyll of a pistil is a 

 Carpel. 



The seed rudiments which produce and 

 contain the macrospores are the Ovules 

 (Fig. 11 b). The outgrowth from the 

 inner wall of the ovary upon which the 

 ovules develop is the Placenta (a). The 

 hollow portion of the pistil, containing the 

 placentae and 'ovules is the Ovary (Fig. 

 9 b). The divisions of the ovarian cavity, 

 which sometimes exist, are called Cells 

 (Fig. 198, &c.), and the partitions which 

 separate them are called Septa or Celi- 



Walls. A point upon a pistil (Fig. 9 d), 

 which lacks its epidermis and permit* 



entrance into the ovary of the pollen- 

 product is a Stigma. A usually non-hol- 

 low portion connecting the stigma to the 

 ovary and narrower than the latter is the 

 Style (Fig. 9 c). 



Since the androecium and gynaecium 

 are capable of producing seeds without 

 the necessity for other floral parts they 

 are commonly known as the Essential 

 Organs, other parts as the Non-Essential 

 Organs. 



The danger of accident as the result of 

 blows, punctures, erosion, or even changes 

 of temperature, to the complex mechanism 

 and delicate structure of the essential 

 organs, and the resulting necessity for 

 their protection, is obvious. In the case 

 under consideration the flowers are so 

 closely crowded upon their supporting 

 branch that their subtending leaf-scales 

 afford the necessary protection. But com- 

 monly this is not the case, and the flower 

 must provide its own protecting organs, 

 if it have any. It must be borne in mind, 

 however, that protection is the least im- 

 portant ofhce which such organs fulfil. 



A series, or apparent or real circle, of 

 such modified leaves, underneath or sur- 

 rounding the androecium, is displayed in 

 the flower of Pulsatilla (Fig. 16) and con- 

 stitutes its Calyx, frequently indicated by 

 the sytnbol K, the several leaves being 

 called Sepals, or Calyx-Lobes, in accord- 

 ance with conditions to be considered 

 hereafter. Commonly there is a second 

 circle between the calyx and androecium, 

 as in the buttercup (Fig. 17 a), and this 

 is called the Corolla, frequently indicated 

 by the symbol C, its several leaves Petals 

 or Corolla-Lobes, according to their con- 

 dition. Rare cases occur in which, al- 

 though but a single circle is present, it is 

 regarded as a corolla. The space between 

 two adjacent petals or corolla-lobes — and 

 the same is true of a similar space be- 

 tween any two organs or divisions stand- 

 ing side by side — is called the Sinus. Oc- 

 casionally the petals will be numerous, 

 forming more than one circle. Petals and 

 sepals are normally not composed of dis- 

 tinct parts, unless it be by a narrowed 

 insertion, called the Unguis or Claw, 

 which is frequently present (Fig. 18 a). 



