Jan. 1899. J BOTANICAL SOCIETY OF EDINBUEGH 153 



double, and its orientation normal. The transfusion tissue 

 was present in the usual amount. 



On examining a transverse section of the fourth needle, 

 I found only two resin canals, right and left of the vascular 

 bundle, embedded in the mesophyll. The transfusion tissue 

 was not so abundant as in the other needles, and the 

 vascular bundle was single. The xylem was towards the 

 convex, and the phloem towards the plane side of the leaf, 

 exactly the opposite of what is found in the normal 

 condition. In the position and number of the resin canals, 

 and the orientation of the vascular bundle, this leaf agrees 

 in structure with what is found in the leaf of I'inus 

 Monophylla, according to the description given by Maxwell 

 T. Masters in the "Annals of Botany," vol. ii. p. 124. 



It may be interesting to notice here that according 

 to Bertrand — "Annales des Sciences Naturelles," series v. 

 vol. XX. — the resin canals of the scale leaves are not 

 continuous with those of the axis, but the photomicrograph 

 of the longitudinal section of the branch of limited growth 

 and interfoliar bud shows distinctly a branch passing from 

 a resin canal at the axis into a scale leaf. I have also 

 found scale leaves of other buds receiving branches from 

 the resin canals of the axis. 



After the third year the primary spirally-arranged 

 green leaves of the pine appear only as dry scales, bearing 

 branches of limited growth in their axils, and most 

 authorities agree that when such scales become changed 

 into green leaves, they are short and flat, in fact, they 

 become the typical rosette-shoot leaves ; but the fourth 

 needle, which has the same origin as the rosette-shoot 

 leaves, is thin and needle-like, and although it shows 

 some of the primary leaf characters internally, still, in 

 outward appearance, it resembles the normal acicular 

 leaves, exhibiting, in fact, a transition stage between 

 the two. 



REFERENCES. 



Dr. V. Tubeuf. — Die Coniferen. 



M. T. Masters. — Annals of Botany, vol. ii. p. 124, 



Bertrand. — Annales des Sciences Naturelles, series v. vol. xx. 



TRANS. BOX. SOC. EDIN. VOL. XXI. M 



