Abietineae (?) from the Cretaceous of New Zealand. 119 
pitting of the top, bottom, and end cells can be seen clearly. It is more 
difficult to determine the exact nature of the pits in the radial walls, but 
there seem to be rows of about three in the tracheide-field where the rays 
cross the spring tracheides, and a smaller number in the regions of the later- 
formed wood. The cells of the edge of the ray have rather irregular 
outlines (see Text-fig. 7), reminding one of the early stages of ray-tracheide 
formation, an Abietinean feature. 
With these characters, the rays of Pence Lindleii are quite unlike those 
of any true Araucarian, living or fossil, and are strikingly similar, as are its 
tracheides, to those of the new fossil. In addition, the distribution of the 
wood parenchyma is alike in the two forms. 
For various reasons, some of which will be dealt with in a later para- 
graph (see p. 122), a new ‘genus’ seems to me to be required to contain 
these two fossils, and possibly some others. Regarding the nature and 
value of these artificial ‘ genera ’ I have recently written at some length (see 
Stopes, 1915 , p. 58 et seq.) before the present data came to light. As will 
be seen on reference to these pages, I take an extremely conservative view, 
and consider that the fewest possible number of such ‘ genera ’ should 
be used. The foundation of the present genus, however, appears to me to 
be essentially necessary. 
Planoxylon , gen. nov. 
[Based on the Greek root nXavaaQai , the same as in Planospores ; the 
suggestion being that the forms comprising the ‘ genus 5 were moving from 
one position to another in a systematic sense — we do not know how near 
any of our present genera this genus-complex was, but presumably, though 
by no means certainly, it lay between the Araucarineae and the Abietineae.] 
Diagnosis. Coniferous wood without, or with occasional, resin canals. 
Regular growth rings. Tracheides with alternating, hexagonally bordered 
pits (2 or 3 rows) in spring wood ; later-formed wood with single rows 
of adjacent or isolated pits. Pits present in tangential walls of late-formed 
wood. Rays almost entirely uniseriate, locally a few may be partly bi- 
seriate. Typical ‘Abietinean pitting’ of ray cells well marked, apparent in 
transverse, radial, and tangential sections. Radial walls of ray cells pierced 
by a small number of pits per tracheide-field (1-3 vertical pairs according 
to position in growth ring), these pits sometimes clearly bordered. Wood 
parenchyma present between spring and last-formed wood of previous 
season. 
The genus founded on the wood of fair-sized branches and trunks. 
In the genus are placed at present two species, viz. Planoxylon Lindleii 
and the new species from New Zealand (see, however, note on p. 120). 
