INTRODUCTION TO CRYPTOGAMIC BOTANY. 49 



such that all question of affinity seems to mo to be at an 

 end, however enticing the points of resemblance are. Conifers 

 are highly-organised Phajnogams, and Club-mosses are the 

 most so of Cryptogams ; but if we take into consideration the 

 immense difference of general structure, and much more of 

 manner of development, without our being able to point out 

 any intermediate plants whose relations on either hand are 

 doubtful, I do not see how we can venture to say that there is 

 any affinity. 



36. Transitions from one group to another may take place 

 in various ways ; as, by the union of the characters of two 

 osculant gTOups in a single species, so as to make it doubtful 

 to which the species belongs, as, for example, in the transition 

 from Uredinece to Tremella ; by the sudden alteration of the 

 mode of development of some particular organ, as in the spores 

 of Eqiiiseta and Ferns ; or by the mutual interchange of many 

 characters, as in Pheenogams. In the monoj^etalous hypogy- 

 nous orders, as, for instance, in Serojyhularineai, SolanacecB, 

 Acantliacece, Blgnoniacece, and Convolvulacece, which are so 

 intimately related that they can neither be technically divided 

 nor arranged in a linear series, we have an excellent example, 

 and so with Apocynece, Gentimiew, Loganiacece, which are simi- 

 larly connected, not only with one another but with some of the 

 above, and even no less intimately with the Epigynous orders, 

 RubiacecB and Gaprifoliacece, as has been shown in an 

 admirable paper of Mr. Bentham's, lately read before the 

 Linnaean Society. Between Conifers and Club-mosses there 

 is no such connection. By a curious diversity, the spores 

 which immediately reproduce the species in the greater part 

 of Fungi, give rise to a sort of prothallus in the rusts and 

 wheat mildews. Here, then, is a slight foreshadowing of the 

 new series of developments in higher Cryptogams, in which the 

 spores produce a prothallus, and, in so doing, at length, by a 

 wonderful chain of analogies, simulate the formation of 

 embryos in Phsenogams. The Club-mosses, and especially 

 the Lejndodendra, are probably the highest limit capable of 

 being reached by Cry])togams, and their mode of fructification 

 the nearest to that of Phsenogams. But there is no connecting 

 4 



