372 BOTANICAL GAZETTE [May 
that the extent of the primary leaves due to wounding is much 
greater than at first appears. 
The possibility of reviving the primary type of foliage by wound- 
ing must be fairly common in the pines, for in addition to the ones 
that have been mentioned, MASTERS (19, p. 258) refers to their 
production after injury in P. edulis, P. Parryana, and P. Khasyana. 
The past summer I have observed it in ten or more species: P. 
canariensis, excelsa, halepensis, Jeffreyi, Laricio and var. ausiriaca, 
monophylla, Pinaster, Pinea, ponderosa, Thunbergii, and tuberculata. 
LOYD, moreover, has produced the primary type of foliage experi- 
mentally in P. ponderosa. He states (18, p. ror; see also original 
article, 17) that “shoots, which normally would bear only thin, 
brown, papery scales, namely the shoots which bear the male or 
_ pollen-bearing cones, may be made to produce true primordial 
leaves by the mere pruning away of the upper part of the shoot 
early in the spring.” HocusTetrer (12) has gone farther, and has 
succeeded in fixing the juvenile foliage in P. Pinea and P. canariensis 
by cuttings, having accomplished in this specialized genus of the 
Abietineae what is common practice in the Cupressineae. He 
states (p. 367): ‘“Stecklinge von Pinus canariensis und Pinea- 
Samlingen, im zweiten oder dritten Jahre abgenommen, wachsen 
leicht an, verharren in der Primordial-form und bilden blaiulich- 
griine Biische mit spiralig einzeln gestellten Nadeln von 
unvergleicher Schénheit.’’ Unfortunately, these “<incomparably 
beautiful” shrubs are but short-lived. Had they succeeded better 
and become disseminated through horticulture, they would have 
afforded a convenient and valuable demonstration of the primary 
type of foliage of the pines. 
In some seedlings of P. Strobus in the third year I have found a 
reversion to primordial leaves where no wounding could be detected. 
The leaves, for example, shown on the branch above and to the left 
of fig. 11, though broader and more closely set than usual, are 
primordial leaves produced after the plant had formed spur shoots. 
Such leafy branches may even originate from a spur shoot, three 
stages of differentiation being shown in the figure. To this point, 
however, reference will be made again. Masters has observed 
(19, p. 258) in P. rigida and P. silvestris that if the main axis © 
