370 BOTANICAL GAZETTE [MAY 
are gradations in structure, however, between the two types of 
foliage. BoRTHWICK (1, p. 153) refers to this feature in his descrip- 
tion of the supernumerary needles of P. Laricio, to which reference 
has been made. He says that “the fourth needle,. . . . 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.” I have 
found very complete series of transitions in form between both 
scale and primordial leaves, and also between these and the whorled 
needle leaves. The latter is well indicated in fig. 10, where the 
upper spur (5-foliate) has proliferated into a branch with primordial 
leaves. It is possible here to tell the spur leaves from the others 
only by their low spiral arrangement and by their slightly triangular 
rather than flat form. In the fascicles illustrated in fig. 3, some 
of the upper bracts have been modified into green seedling-like 
leaves. The needles of these fascicles, too, are flatter, shorter, and 
more like the primordial type. This is especially true of the needles 
of the fascicles in the younger plant shown in fig. 1. More definite 
reference to these points will be made in a future paper dealing 
with the internal structure. The morphological evidence, however, 
seems sufficiently clear that the spur shoot leaf is only a specialized 
primordial leaf, just as the scale leaf is also a modification of it. 
The transformation to both types of foliage occurs at somewhat 
different stages in the life of the seedling of various pines. O 
P. monophylla, SARGENT (24, p. 51) says: “primary leaves are 
the only ones produced during the first five or six years in the life 
of the plant”; while Brirron (3, p. 14), in referring to this feature 
in P. cembroides, states: “juvenile leaves of this and other nut 
pines are produced for the first five years or more, often to the 
exclusion of all others . . . . the new ones shorter as the buds 
of the fascicled, needle-shaped leaves develop in their axils. 
Masters (21, fig. 1, p. 586) has figured the persistent primordial 
leaves of one of these, P. Parryana. He previously figured those 
of P. Pinea, a form in which he notes that they were observed long 
ago by Linnaeus (MAsTERs 19, p. 258 and fig. 8). Of the last 
mentioned species, ELwEs and HEnry (7, p. 1120) state that “the 
primary leaves are produced . . . . for several years, in mixture, 
