452 Dr. Wlllshire on some points of Vegetable Structure. 



some years before, we think a true illustration of their pri- 

 mary development is afforded, and in which the spiral direc- 

 tion is at the same time very plain. It is true that some writers 

 have stated their belief, that these spiral filaments are invest- 

 ed by a primary membrane, and hence that they are only se- 

 condary in appearance ; but all that we conceive is, that they 

 are surrounded by a sort of mucus, probably cytoblastemic. In 

 the many examples found in Orchideae of fibro-membranous 

 tissue, the fibre can only be considered as forming the se- 

 condary layer. It appears to us rather difficult to say whether 

 the branched filaments which connect together the granules 

 of pollen in many plants are to be regarded as primary or not. 

 In the earlier periods of antheroid evolution none are to be 

 seen, it being only after the dissolution of the original cells 

 in which the granules were formed that they appear. 



In many of the lower orders of plants the formation of pri- 

 mary fibre is evident ; the mesothallus of many lichens and the 

 filaments of certain fungi illustrate the point ; but in these 

 orders great care, we conceive, must be used in drawing our 

 conclusions, since much of fibrous and spiroid tissue — the 

 latter in particular — is in them decidedly of secondary deve- 

 lopment. The spiroid fibres of the cells of Sphagnum, and 

 the same structure which we are led to believe may be here- 

 after observed in Dicranum glaucum and Octoblepliarum albi- 

 dum, as well as the spiral filaments of Trichia and Junger- 

 mannia, are of course all secondary. 



Turpin, in his reduction of vegetable forms to elementary 

 types, assumed two conditions as the lowest ; the one called 

 Protospheria simplex, in which the development was sphe- 

 roidal and cellular ; the other Protonemata simplex, in which 

 the evolution was filamentous and thread-like. These states 

 of development have been assumed as primary and springing 

 from a mere structureless, gelatinous phycomater or matrix, 

 and also that the mere evolution of either of these forms — a 

 simple cell or thread — constituted the lowest conditions of an 

 entire vegetable organism. This theory in some points, how- 

 ever, is to us too vague to offer a support to the theory of 

 primary filamentous development, since we conceive that the 

 Protonemata is here secondary upon the Protospheria. There 

 is only one argument in its favour, and that is, in its agree- 

 ment with a law of physiology, namely, that as we get lower 

 down in the scale of vegetable bodies, the complications of the 

 elementary powers of which the higher orders are made up 

 become fewer and fewer, until at last we get so low that scarce- 

 ly any complications exist at all, the mere exemplification of 

 the element as it were constituting the whole individual ; but 



