DESCRIPTION OF PLANTS. 177 



character of Campanula, above cited ; so that it suffices for the 

 distinction of Campanula from its allied genera to give the following 

 brief abstract, or diagnosis : 



" Campanula : Calyx 5-parted. Cor. mostly bell-shaped, with 5 broad 

 and shallow segments. Anthers free ; filaments dilated at the base. 

 Stigma 3-5-fid. Capsule not elongated, 3-5-celled, opening by lateral 

 pores outside the segments of the calyx." 



It is seen at once that this diagnosis fails to furnish the complete 

 notion of the genus which is obtained from the descriptive character, 

 and that it does not suffice to indicate the position of the genus, 

 either in a Natural or Artificial classification. On the other hand, 

 for its own especial purpose (that is, of indicating the distinctions 

 between allied genera), it may be even still more reduced, as is often 

 done in works describing the plants of a limited district, where only 

 a few genera occur in the natural order ; for example, we might 

 give diagnoses of the British genera of Campanulacese in this way 



A. Corolla rotate, segments linear ; anthers cohering at the base. 



1. Jasione. 

 Corolla rotate, with linear segments j anthers free. 2. Phyteuma. 



B. Corolla mostly bell-shaped, with broad and shallow segments ; an- 



thers free. 



Capsule not elongated, opening by lateral pores outside the seg- 

 ments of the calyx 3. Campanula. 



Capsule linear-oblong, prismatic, opening by lateral pores be- 

 tween the segments of the calyx 4. Specularia. 



Capsule half-superior, opening by 3-5 valves within the seg- 

 ments of the calyx 5. Wahlenbergia. 



Specific Character. The specific character of a plant should 

 mention all the constant distinctive peculiarities of a species. On 

 the one hand, it should exclude the generic characters which ally it 

 to other species of the same genus ; on the other, it should exclude 

 the inconstant characters which distinguish its own varieties. But 

 the character of its ordinary varieties, if such exist, may be given 

 in a supplementary paragraph, like that appended to the full 

 generic character. The distinctive characters of species are usually 

 found in the organs of vegetation, as the root, stem, leaves, bracts, 

 and inflorescence, or in the habit or duration of the plant. The 

 floral organs mostly only give specific characters in their less im- 

 portant peculiarities as in the shape and relative magnitude of 

 the petals, the external characters of the fruits and seeds, &c. 

 the more remarkable peculiarities being of generic value. The 

 supplementary notices appended to the strict character of the spe- 

 cies generally relate to the ordinary dimensions of the plant, the " 

 colour, taste, smell, &c. of its organs ; these are the marks by which 

 the varieties are usually characterized, as will be seen by referring 

 to any catalogue of varieties of the ordinary cultivated vegetables. 



