178 SYSTEMATIC BOTANY. 



The specific character will necessarily vary in length according to the 

 richness of a genus in species, some containing many hundreds, while 

 others comprise but a single one. When the genus contains but a single 

 species, as the Hop (Humulus Lupulus), the generic character alone suffices 

 for distinguishing it ; but a specific character is even then given with 

 advantage, indicating points which are not included in the strict generic 

 character. Where a large number of species exist, the genus is generally 

 broken up into artificial sections, characterized by some mark occurring 

 regularly in a certain number, w r hich are thus placed under one head : 

 this saves the necessity of repeating that character for each species. It 

 is also common in modern works to combine a diagnosis with the specific 

 character, by marking in italics the especial distinctive marks of each 

 species occurring in a particular group. 



The following examples will make this more clear : 



Of Syringa, L., only six species are described in De Candolle's ' Pro- 

 dromus,' being all that were known in 1844. The specific character of the 

 common Lilac, Syringa vulgaris, could thus be given in a few words : 



" S. vulgaris, L. Leaves cordate or ovato-cordate, quite smooth and of 

 even colour ; limb of the corolla subconcave." 



Four varieties are characterized, chiefly distinguished by the colours of 

 the blossoms. 



Turning to the genus Campanula in the same work, we find no less 

 than 182 species. Being a very natural genus, the species are kept toge- 

 ther under one generic name, but, for convenience, they are arranged in 

 sections and subsections. Thus fifty-eight of them are characterized by 

 the presence of appendages on the sinuses of the calyx, such as we find in 

 the garden Canterbury Bell (Campanula Medium), while the remainder 

 are without these. The second section, of 124 species (among which are 

 included all our native kinds), is further divided into subsections, cha- 

 racterized principaUy by the peculiarities of the capsule, and these, again, 

 into groups according to the kind of inflorescence, &c. ; so that when we 

 come to the specific character itself none of these points have to be re- 

 peated, and the definitions are restricted within very narrow limits, as for 

 instance : 



" C. rotundifolia, L. Radical leaves stalked, cordate, rounded, crenato- 

 dentate ; stem-leaves linear or lanceolate ; teeth of the calyx awl-shaped, 

 erect, one-third the length of the bell-shaped corolla." 



In a work devoted to a limited flora, as that of Britain, where there exist 

 only eight species of Campanula, we may adopt the sectional divisions, 

 and limit the specific character as above, or give a longer character, in- 

 cluding the marks of the sections; the latter plan is the better, where 

 space is not an object, since it makes the character itself more instructive. 

 Thus, in the ' British Flora/ we find 



" C. rotundifolia, L. Glabrous ; root-leaves subrotundo-cordate, cre- 

 nate (very soon withering), lower cauline ones lanceolate, upper linear 

 entire ; flowers solitary or racemose, drooping ; calyx-segments subulate ; 

 capsule drooping, with the clefts at the base." 



In Babington's ' Manual,' on the contrary, where the subsections 

 founded on the capsule are adopted, this mark is omitted in the essential 

 character : 



" C. rotundifolia, L. Radical leaves cordate or reniform, shorter than 

 their stalks ; stem-leaves linear, the lower ones lanceolate ; flowers one or 



