6 BOTANICAL GAZETTE [JULY 
shoots found in intimate association with the Pityoxylon here de- 
scribed, which unquestionably belong to the genus Pinus in the 
narrower sense, have the double bundle which is characteristic 
of the hard pines,® as has been learned by one of us from a micro- 
scopic investigation of their structure. They are also provided 
with the persistent foliar sheaths, which are a striking feature of 
the hard or pitch pines in contrast to the soft pines, which have 
deciduous sheaths. All the numerous cone scales found in intimate 
association with the wood, illustrated in our figs. 1-7, are equally 
characteristic of the hard pines, for they have the thickened apophy- 
sis and median umbo, which are unfailing features of that group. 
In the case of our Pityoxylon, however, we find universally present 
the tangential pits of the autumnal tracheids, which are character- 
istic of the existing soft pines.7 STRASBURGER, however, states 
that he has found tangential pits to be present in the autumnal 
wood of Pinus canariensis and Pinus rigida. Mayr® has also 
called attention to the occasional occurrence of tangential pits in 
the autumnal wood of one group of the hard pines. This feature 
has also not escaped the notice of CoNnWENTz. One of us has 
observed the very frequent occurrence of tangential pits in the — 
autumnal wood of the cone in various species of hard pines, where — 
they are quite absent in the vegetative wood. This is the case, for — 
example, in the woody axis of the cone of P. Pinaster, the vegeta~ _ 
tive wood of which is described by Kraus? as having no tangential | 
pits. P. palustris too, although it is a characteristic hard pine, in the 
absence of tangential pits from its autumnal wood,*° possesses these — 
in great abundance in the.autumnal wood of its cone, in both the | 
annual rings present. These two examples will suffice to illustrate — 
the fact that tangential autumnal pits, such as are ordinarily absent — 
in the wood of hard pines, are generally. present in their cones. It | 
may be inferred from the mode of their occurrence that tangential 
~ 6 Coutrer and Rose, Synopsis of North American pines based on leaf-anatomy- | 
Bot. Gazetre T1:256, 302. 1886. 
7 OW, Anatomy of the Coniferales. Amer. Nat. 38:243. 1904. STRAS~ 
BURGER, Ueber den Bau und die Verrichtungen der Leitungsbahnen in den Pflanzen. — 
. Nordamerikas. 
° Beitrage zur Kenntniss fossiler Hélzer, 
p- 25. 
© PENHALLOW, Joc, cit., 204. 
