246 BOTANICAL GAZETTE [MARCH 
on outermost tracheids of the summer wood, and ray tracheids with almost 
smooth walls. In P. excelsa the needles are in fives and the umbo of the cone 
scale is terminal. The ray pitting of the tracheids, too, is of the large simple © 
type (Grosseiporen). It thus belongs to subsection CemBra, and having eee 
cones and thin cone scales belongs to the Sirobus group. They note that, ‘ 
regards width of spring-tracheids, the American species, belonging to Ps 
section HAPLOXYLON that most closely approach it, likewise belong to the 
group Strobus,”’ but draw attention to one difference, the thick horizontal walls 
of the ray cell of P. excelsa, which, according to PENHALLOW, is not character- 
istic of the Cempra type. P. Gerardiana has a thick cone scale with central 
umbo, three leaves to the fascicle, and so belongs to the subsection PaRa- 
CEMBRA Of KOEHNE, which has small ray pitting on ae —— Like the 
other haploxylic forms, it has uniseriate tracheary pit 
The other three species, P. longifolia, P. Khasya, rs P. Merkusti, have 3, 
3, and 2 needles, respectively, but “agree not only in the diploxylic nature of 
the leaves, the persistent nature of the sheath of the dwarf shoot, and the 
possession of a central umbo on the thick cone-scale, but also in that the transi- 
tion from spring wood to summer wood is sudden (except in P. Khasya), the 
outermost tracheids of the annual ring do not universally bear pits on the 
tangential walls, the pits on the radial walls of the spring tracheids are often 
2-seriate, and the ray tracheids are denticulate.”’ 
The authors consider that the pitting of P. Merkusii is of extreme interest, 
showing a transition between that ‘of the cordaitean or araucarian forms and 
the ordinary abietineous type. The pits are ‘‘in one, two, or three rows, . 
in peculiar nests, of 3 or 4.’’ These nests are surrounded by “‘Sanio’s rims.” 
The similar condition found by Santo himself in the root of P. silvestris seems 
to have been overlooked, but at least P. Merkusii is the only pine so far 
described with nests in the stem. They compare this cluster pitting to the 
well known condition described by PENHALLOW in Cordaites Newberryti, and 
to that in Cedroxylon transiens of Goran. These clusters of pits correspom 
to the “starlike” arrangement which Goran considers as intermediate 
between araucarian and typical abietinean pitting. 
With regard to ecological features, they state: “the tracheids are shortest 
(3 mm.) in the xerophilous Pinus Gerardiana, attain a length of 4 mm . in 
P. excelsa and P. longifolia, and 4.6 mm. in P. Khasya, and the relatively great 
length of 7 mm. in the tropical P. Merkusii. The size of the tracheids is also 
commented upon, but a separate article dealing with this point is in process of 
publication. It has a thick cuticle and hypoderma, much transfusion tissue 
and “a great development of resin ducts,” all in excess of P. excelsd. the 
other three they state: “‘as regards leaf structure, all have stomata on all their 
faces. P. longifolia, the most clearly tending to xerophily, has the thickest 
cuticle (hough not 80 thick as P. Gerardiana), and P. Khasya has the thinnest 
P. crieertgese 
