126 CHAKACTERS USED IN CLASSIFICATION. 



of facts. Positive characters are constcmt or inconstant ; — all 

 seeds produced by plants of the same species have the same 

 structure ; all plants which grow from these seeds produce 

 other seeds, similar to those from which they have had their 

 origin ; of com-se the characters derived from the structure of 

 these seeds are constant. But among these plants some are 

 large and others small ; some may have white corollas, some 

 red or blue ; some are more fragrant than others : of course, 

 size., color., and odor offer inconstant characters. 



160. All real science in Botany must rest ujpon constant cliar- 

 acters ; therefore these characters are much more important 

 than the others. Constant char acters may he isolated or coexist- 

 ent. The petals of the kanunculus acris (butter-cup) have a 

 gland in the form of a scale ; this character, although constant, 

 is isolated., for it is not necessarily connected wdth any other 

 characteristic trait. The calyx of the Ca^npaiiula rotundifo- 

 lia (blue-bell) adheres to the ovary ; this must of necessity be 

 simple, or without divisions, and the. corolla and stamens at- 

 tached to the interior of the calyx. The character of the ad- 

 herence of the calyx to the ovary brings in its train several 

 other characteristics ; it is then coexistent., and is more import- 

 ant than the isolated character. 



161. Two orders of characters are derived from the two great 

 divisio7is of vegetable organs — those of vegetation and 7'ej[}roduc- 

 tion. The characters of rejyroduction are numerous and often 

 coexistent', one character serving as an index to many others. 

 It is seldom that plants which resemble each other in their 

 characters of reproduction differ much in their characters of 

 vegetation. For example, all plants with four didynamoiis 

 stamens attached to a monopetalous, labiate corolla, and four 

 seeds lying uncovered in a monophyllous calyx, have an angu- 

 lar stem, and opposite leaves. On the contrary, it frequently 

 happens \)ii2X jylants which resemble each other by tJie characters 

 of vegetation., differ by those of rejproduction. Labiate and 

 caryophyllous plants agree in having their leaves opposite., and 

 yet there is no resemblance in their flowers. This considera- 

 tion alone would seem sufficient for establishing the superior 

 importance of the characters of reproduction over those m vege- 

 tation. The seed unites in itself the characters both of repro- 

 duction and vegetation. The embryo is the commencement of 

 the new plant., and it offers us the first characters of vegetation ', 

 but its situation in the fruit., the number., form^, and con- 

 sistence of its envelope., are characters which belong tofructificor 

 tion. 



Different kinds of positive cliaracters. — 160. Constant characters, of what kinds ? — 161. Characters 

 •f reproduction and vegetation. 



