146 BOTRYCHIU.M VIRGINIANUM. RATTLE-SNAKE GRAPE-FERN. 



scrlptive botany. He looks upon the stipe as a simple structure, 

 which finally divides, the division taking place about the middle of 

 the frond. But instead of being a simple structure, we know that 

 in its origin it is compound. The fertile portion is one whole 

 frond, having primarily a separate stipe which has been clasped by 

 the stipe of the barren frond, and the two have grown so closely 

 together, that to all appearances, and quite accurately enough for 

 botanical description, it appears as one simple stipe, out of which 

 the barren frond seems to grow. In this species the whole stipe of 

 the barren portion has united with the other, and this is the reason 

 why it seems sessile, or without any leaf stalk ; but in other species 

 it is only partially united, and then the frond seems stalked; 

 or again it is wholly free, and there are two distinct stipes, as 

 the petioles of ferns are called, and it is from these comparisons 

 that we learn how much the early union or early freedom of parts 

 has to do with final results in form. In earlier times, before this 

 knowledge was gained, the divisions of the leaves were deemed 

 important characters; but while leaf-divisions involve the question 

 of an union or freedom of parts, they are parts that in their final 

 development are still leaf-blade, and are of less consequence than 

 the changes which occur in the earlier stages of plant life. Hence, 

 if the five divisions of the frond were to be found united, so as to 

 make one uniform surface, the collector might reasonably suspect 

 he had but a form o{ BotrycJiiuui l^irginiaiiuiu ; but if he were to 

 find one as finely divided as this, but with the fruiting stalk more 

 widely separate from the barren stalk, he would be much more 

 likely to have another species. 



Our morphological lesson may be carried further, so as to show 

 how the fruit is formed out of leaves or leafy substances. The 

 fertile frond was, in early life, precisely the same as the barren 

 one; but the power of union was greater in one than the other, 

 and the final divisions in the barren frond (a, a, in Fig. i) have 

 been rolled up to form the spore cases (a, a, in Fig. 3). There is 

 no reason, therefore, in the nature of things, why sometimes 

 green leafy blades may not appear on weak fertile fronds, and 



