52 BOTANICAL GAZETTE {yuLy 
Picea, while European authorities note their presence only in the sum- 
mer wood. In the seventeen species of Picea which I examined, I 
found spirals well developed in the summer wood of the first few 
years’ growth, usually from the first or second to the tenth year. In 
older woods they are very sporadic in their development, in certain 
regions appearing well developed, but usually showing at best only 
feebly. In wounded areas they showed a tendency to be strongly 
developed. In two species, Picea sitchensis Carr. and Picea Maxi- | 
mowtczit Regel, the spirals were very strongly developed in the spring | 
as well as the summer wood (fig. 6). Furthermore, in both of these 
species, spiral thickenings were well developed in the marginal and 
interspersed tracheids of the rays (fig. 5). They occurred in the ray 
tracheids in both the summer and spring wood. In other species of 
Picea this condition could be made out in the tracheids of the rays of 
the summer wood. In other words, the ray tracheids appear to fol _ 
low closely the wood tracheids. Where spirals are strongly developed i 
in the latter elements, they will appear usually in the former. + 
In Larix the spirals were observed occurring in the first few years: 43 
growth, but not so well developed as in Picea. In the mature wood 
and in the ray tracheids, the spirals are likewise sporadic in theif 
appearance, and may or may not be noticeably developed. Only ; 
Mayr, but states (loc. cit.) 
Sections from specimens of Uf 
ow the spirals well developed 
imens and less well develo 
In Pinus, as has been noted, Goruan asserts the absence of spit@ 
yet PENHALLOW (op. cit, 41) has described them as occurring 
