114 Observations on the Vascular System of Fe7iis. 



Link, (Elemens de Botanique, T. I, p. 132,) as quoted by Hugo 

 Mohl in his elaborate treatise ''De Structura Caudicis Filicum 

 Arborearum,"* states the wood to be '■^almost wholly made up 

 of large spiral vessels.''^ Decandolle, (Organographie, T. I, p. 

 232,) as quoted by Mohl, mentions that they contain many an- 

 nular ducts (vasa scalar iformia) without alluding to spiral vessels. 



Lindley, (Int. to Bot., 1st edit., p. 22,) speaking of spiral ves- 

 sels, says, that " in flowerless plants they are for the most part 

 altogether absent ; the only exceptions being in Ferns and Lyco- 

 podiaceas," and adds, " m these they no doubt exist ; Mr. Griffiths 

 has succeeded in unrolling them in Lycopodium denticulatum.^^ 



Mohl, in the treatise above referred to, in which he describes 

 and figures the vasascalarifor7nia, says, (p. 48,) " Num in juni- 

 oribus plantis et in junioribus partibus adultarum harum planta- 

 rum vera vasa spiralia occurrant exponere nequeo, quum has partes 

 inquirendi occasio defuerit ;" and again, in a note on page 51 of 

 the same treatise, he says : 



" Schultzius quidem (Flora, 1828, Tom. I, p. 154) commemo- 

 rat propria vasa inesse, ceterum accuratiori eorum descriptione 

 omissa ; equidem vero in nulla earum formationem inveni pro- 

 priis vasis adnumerandum." 



When distinguished observers disagree so much in their state- 

 ments, it often happens that their accounts can be reconciled by 

 the discovery of some fact not observed by either, which will 

 explain the apparent contradictions. I hope that the knowledge 

 of the point of structure which I am about to describe, will have 

 Ihis bearing upon the present question ; for it shows, that those 

 who maintain the existence of spiral vessels in ferns, may actu- 

 ally have obtained, what, when not carefully examined, might 

 easily be mistaken for spiral vessels ; while those who deny the 

 existence of spiral vessels, may have observed the same organs 

 without attempting to uncoil them, or if they attempted they 

 may have failed, owing to the age of the plant or some other 

 cause. 



The fact to whicli I would invite the attention of botanists is 

 this, viz. The ducts of feigns (Annular ducts of Lindley, Vasa 

 scalariformia of Decandolle and Mohl) can be imcoiled spirally 



* Published in the splendid work, Icones Plantarum Crj'ptogamicarum, quas in 

 iUnere annis 1817 — 20 per Brazilian! collegit et descripsit Carol. Frideric. Philip. 

 de Martius. MonaChii, 1828—34. - 



