32 INTRODUCTION TO CllYPTOGAMIC BOTANY. 



sible, it is necessary to consider how far they are related to 

 phaenogamic plants, and whether there is any close affinity 

 between any particular order of the two series, which can, with 

 very great probability, be indicated. Mere cases of analogy 

 have little weight in such a consideration. Such cases are 

 presented by the three natural orders, Balanophoracece, Cytin- 

 acece, and Raflesiacece, on the one hand, and by Podostemacece 

 on the other. In the latter case, there is a great want of 

 spiral vessels, and the forms of many Cryptogams are curiously 

 represented, but there is nothing about the fructifying organs 

 to cause the least perplexity, and the best opinion is that they 

 are reduced Lentihularice.* The foliaceous expansion is of 

 little consequence. All such productions are mere offsets from 

 the axis, whether horizontal or vertical, which are often dis- 

 pensed with altogether, insomuch that, as regards a question 

 of this kind, the Schleidenian doctrine, that " plants have no 

 leaves," is perfectly true.-f- The Ehizanthous order mentioned 

 above, in habit, parasitic mode of growth, and substance, bears 

 a close resemblance to Fungi. If, for instance, a Pilostyles be 

 compared with such Fungi as Podisoma and Cyttaria, which 

 grow upon living branches of Juniper and Evergeen Birch, 

 producing a new crop year by year from the old mycelium, 

 there is a striking resemblance in the way in which the indi- 

 viduals are dotted over the stem. In the fungus, however, 

 there is not a doubt that the threads of the mycelium penetrate 

 the cells of the matrix, and burst forth in the shape of new 

 individuals. Mr. Brown failed to prove that this was the 

 case in Pilostyles ;l but even supposing that he had been 

 able to show that the rhizoma crept under the bark, and pro- 



* Willdenow referred two genera toCrj-ptogSims,£landovia=Apinagia, 

 and Dufourea=Trist{cka, the former to Hepaticse, the latter to Ferns, 

 Mag. der Ges. Nat. Freunde, zu Berlin, vol. iii. p. 200, and vol. vi. p. 63. 

 t Such expansions may or may not have vascular tissue. In the 

 former case, they would be mere offsets from the bark. It is obvious 

 that the possible or actual formation of a bud in the axil of each leaf, is 

 favored by the presence of vascular tissue. 



X When Mr. Brown was preparing his memoii- for the Linnaean 

 Transactions, he was so kind as to show me his specimens, and to have 

 some conversation on the analogous points in Podisoma. His observa- 



