io86 
Thompson.— The Anatomy and 
The tracheide walls sometimes show tertiary spiral striations such 
as are characteristic of Taxus and Pseudotsuga , and according to Bailey 1 
are of sporadic occurrence in all the Pineae. Fig. 14 gives their cha- 
racteristic appearance in E. californica . They appear to be of very 
sporadic occurrence. Their presence is not a specific character, nor are 
they more frequent in young wood, as Bailey found to be the case in 
the Pineae. They supply one more point of resemblance to the tracheides 
of the Conifers. 
Another type of spiral thickening to which Boodle and Worsdell 2 has 
called attention is photographed in Fig. 15. These thickenings are broader 
and less numerous than those of the other type. Boodle and Worsdell 
observed that they appear to be continuations of the mouths of the pits. 
The relation to the pits is plainly shown in Fig. 15, especially in the upper 
part of the field. In many places the relation is not so obvious on account 
of the fact that the section may not include the underlying pit. It is plain 
that these thickenings have no connexion whatever with those of the usual 
type. They have also been observed in the genus Widdringtonia > one 
of the Cupressineae. 
Still another feature which occurs sporadically in the tracheides of the 
Coniferales and only in that family is present in Ephedra , namely, the so- 
called trabeculae. By this term is meant a series of lignified septa occurring 
all in the same horizontal line in a single radial row of elements. When 
seen in radial section (Fig. 16), they present the appearance of a continuous 
row of lignified bars crossing the field. Their occurrence is so uncommon 
and sporadic in any wood that little account is taken of them in the litera- 
ture of wood structure. They serve, nevertheless, as another addition to the 
list of Coniferous characters possessed by Ephedra. 
There is just one other point in connexion with the tracheides of 
Ephedra to which attention should be called, namely, the frequent presence 
of resin plates. Resin is often deposited in the tracheides in the form of 
spool-shaped plates. In Fig. 16 the small tracheide at the left of the large 
central vessel contains several of them. Although this is the prevailing 
form, the resin is sometimes deposited in globules or larger masses. The 
spool-shaped plates bear a strong resemblance to those of the wood of 
certain Conifers, notably the Araucarians, in which they become a charac- 
teristic feature. 
All the characteristic features of the tracheides of Ephedra are, then, 
also characteristic of the tracheides of the Conifers ; the arrangement of the 
pits, the structure of the individual pits, the bars of Sanio, tertiary spirals, 
trabeculae, and resin plates. No single family of the Conifers possesses all 
these features, so that it would be difficult to connect Ephedra from the 
1 The Structure of the Wood in the Pineae. Bot. Gaz., July, 1909. 
2 L. A. Boodle and W. C. Worsdell. Annals of Botany, 1894. 
