6i6 
Notes . 
In fact the primary structure is endarch , just as in the stems of recent 
Coniferae and Cycadaceae \ 
In March of this year my friend Mr. R. Kidston, F.G.S., called my 
attention to certain sections of Araucarioxylon in his possession, 
which showed distinct strands of primary wood in the pith of the stem. 
Mr. Kidston, with his accustomed generosity, lent me his sections 
and specimens for further investigation. Only the chief results can 
be given here ; a full illustrated description will, I hope, appear 
later on. 
The specimens in question are of two very distinct types. The 
one, which we will first consider, will be named provisionally A raucari- 
oxylon fasciculare. Mr. Kidston’s specimen came from the Loch 
Humphrey Burn in the Kilpatrick Hills, Dumbartonshire, where it 
was found by Mr. John Renwick in 1898. Its horizon is given as that 
of the Calciferous Sandstone series, and it is thus of about the same 
antiquity as the well-known Lower Carboniferous fossils of Burntisland 
and of Arran. I find in the Williamson collection, sections (C. N. 
1378-80; 1391-93) of a stem showing a perfectly similar structure; 
this specimen was derived from the Carboniferous Limestone, near 
Haltwhistle in Northumberland. 
The pith of A. fasciculare is small, having a maximum diameter of 
about 2 millim. in the Kidston specimen, and about 3 millim. in that 
from the Williamson collection. The pith itself consists of short- 
celled parenchyma, and presents nothing remarkable, but around 
its periphery is a ring of eight or nine distinct strands of primary 
wood. These strands show a gradation in size; the smaller are 
imbedded in the outer layers of the pith ; the larger are beginning to 
enter the surrounding zone of secondary wood, through which they 
can be traced for some distance in the different sections. These 
strands, which are thus on the point of exit, are most conspicuous 
objects in the transverse sections, attaining a diameter of from -8 millim. 
to 1 millim., with an approximately circular contour. The smallest 
elements lie almost in the middle of the strand, or slightly nearer its 
outer surface; in one case their spiral markings were clear. The 
structure of these primary strands is thus mesarch , as in those of 
Lyginodendron Oldhamium. The large primary tracheides surrounding 
the protoxylem are spiral, reticulate or pitted. 
1 Exceptis exceptandis ; cf. Scott, On Peduncle of Cycadaceae, Annals of Botany, 
vol. xi, 1897. 
