286 



ORGANOGRAPHY* 



When the stigmas are united, the number of parts in the 

 compound stigma is usually indicated by radiating furrows, or 

 grooves. When the stigmas unite and form a compound body 

 upon the top of the style, which is larger than it, this compound 

 stigma or head is said to be capitate \ and this head may be 

 either globular, as in Daphne {Jig. 638), or hemispherical, as in 

 the Primrose {fig. 567), or polyhedral, or club-shaped, or peltate 

 or shield-shaped, as in the Arbutus {fig. 637), and Poppy {fig. 

 426), In the Violet {fig. 639), the stigma presents an irregular 

 hooded appearance. 



Fig. 637. Fig. 638, Fig. 639. 



Fig. 637. 5. Peltate stigma surmounting the style,*, of a species of Arbu- 

 tus. Fig. 638. Pistil of Daphne, o. Ovary, st. Style, stig. Stigma. 



Fig. Q39. Pistil ot Pansy (Viola tricolor), cai. Calyx, o. Ovary, sty. 



Style, surmounted by an Irregular hooded stigma. 



4. The Thalamus, Eeceptacle, or Torus. 



The extremity of the peduncle or pedicel, or the part of the 

 axis upon which the diiferent whorls of the flower are arranged, 

 has been variously distinguished by botanists as the thalamios, 

 receptach, or torus. The use of these names indifferently has 

 often led to much confusion; and the uncertainty is still further 

 increased in consequence of the terms receptacle and torus being 

 also sometimes applied in a different sense. Thus that of re- 

 ceptacle is employed in a special manner, as already mentioned 

 (page 186), to indicate an enlarged peduncle bearing a number 

 of flowers ; while the term torus is used by some botanists as 

 synonymous with disk. To prevent confusion, therefore, it 

 would be far better to limit the terms receptacle and torus to 

 their special applications ; and to confine the term thalamus to 

 indicate the apex of the peduncle or pedicel, or the part of the 

 floral axis upon which the different whorls of a solitary flower 

 are arranged. In this sense it has been used in this volume. 



In the majority of plants, the thalamus is a little flattened 

 surface or point, and accordingly presents nothing remarkable ; 

 in other plants, however, it becomes much enlarged, and then 

 assumes a variety of appearances, and thus modifies to a con- 



