368 NODES OF VISCUM BKANCHES. [BOOK i. 



were continuous, and the state of articulation was solely de- 

 pendent upon the non-continuity of the vessels of the bark. 

 Dutrochet again averred, before the French Academy, that 

 his views were right. Here, I believe, the matter has rested. 

 I have taken some pains to satisfy myself which of these 

 theories is correct. I have examined portions of the plant, 

 both young and old, and at all portions of the nodal places, 

 and I fully concur with Decaisne in stating that the true 

 woody and vascular structure of Viscum is perfectly con- 

 tinuous through the nodes ; that there is no transverse and 

 separating layer of cellular tissue or pith in this portion of 

 the plant, but that the connection of the inner layers of the 

 bark is broken up at the nodes. Viscum album has not an 

 articulated stem, in the proper sense of the word. The 

 vascular structure of Viscum album is by no means so entirely 

 composed of those peculiarly marked and rather elongated 

 cells as is generally drawn and stated. Kieser's representa- 

 tions are often copied, but they only represent a part of the 

 vascular apparatus ; no doubt, a great portion of the woody 

 matter is composed of cells quite different from those met 

 with in the wood of Exogens ; but if the young wood or first- 

 formed bundles be examined, plenty of very long annular 

 ducts and (to me) spiral ducts, with the fibre unreliable, 

 however, as far as I have been able to detect will be found. 

 I may also remark, that the long pleurenchymatous cells 

 surrounding the first-formed vascular bundles are carried 

 along with the latter to the centre of the plant, around the 

 pith of which they may be found, a circumstance somewhat 

 analogous to that stated by Decaisne to take place in Meni- 

 spermaceae." (Annals of Natural History, ix. 84.) 



All the divisions of a stem are in general terms called 

 branches (rami); but it is occasionally found convenient to 

 designate particular kinds of branches by special names. 

 Thus, the twigs, or youngest shoots, are called ramuli, or 

 branchlets, and by the older botanists flagella; the assemblage 

 of branches which forms the head of a forest tree is called 

 the coma : cyma is sometimes used to express the same thing, 

 but improperly. Shoots which have not completed their 

 growth have received the name of innovations, a term usually 



