114 Observations on the Vascular System of Ferns. 
k, (Elemens de Botanique, T’. I, p. 132,)as quoted by Hugo 
ais 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 éesigbigownia) without alluding to spiral vessels. 
Lindley, (Int. to Bot., 1st edit., p. 22,) speaking of spiral ves- 
sels, says, that “in io ivebioss plhinrty they are for the most part 
altogether absent ; the only exceptions being in Ferns and Lyco- 
podiacee,” and adds, “in 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 vasa scalariformia, ‘says, (p. 48,) “ Num in juni- 
oribus plantis et in junioribus partibus adultarum harum planta- 
rum vera vasa spiralia occurrant exponére nequeo, quum has partes 
inquirendi occasio —— 7” and again, in a note on page 51 of 
the same treatise, he sa 
-’ “Schultzius quidem ( Plora, 1828, Tom. I, p. 154) commemo- 
rat propria vasa inesse, ceterum accuratiori eorum descriptione 
omissa ; equidem vero in — 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 wledge 
of the point of structure. which Lam about to describe, will have 
this 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 Sant or some memes 
cause. 
The fact to which I seetdd invite the attention of sana is 
this, viz. The ducts of ferns (Annular ducts of Lindley, Vasa 
Fasciitis of Decandolle and Mohl) can be wneoiled in 
“> Published i in the splendid work, ied Plantarum Cryptogamicarum, quas 
itinere annis 1 20 pe r Breziliam collegit et wera Carol. Friderie. Pip 
de Martius. Mo finch 1828—34. : 
