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the floral organs, and the seeds were known long before their true 
nature was appreciated. 
The stem has the general features of a modern conifer, except 
for the much larger pith, sometimes as much as 10 em. in diameter, 
and often discoidal in consequence of the rapid elongation of the 
stem. Casts of this discoidal pith are frequently found as separate 
fossils and the early writers gave them the generic names Artisia 
or Sternbergia. Structurally the secondary wood is much like that 
of modern Araucarias, the chief feature being the dense crowding 
of the bordered pits of the tracheids into alternating series, often 
with hexagonal outlines. Many anatomical types of wood struc- 
ture have been named (Jesoxylon, Pitys, Callixylon, Mesopitys, 
Caenoxylon, Parapitys, etc.). 
The pollen was produced in sacs between spirally arranged 
bracts on a catkin-like axis. The seeds were borne in similar 
catkins and were usually bilaterally symmetrical and winged. A 
large variety of seeds as well as catkins (Cordaianthus) occur as 
impressions in all parts of the world, and petrified material has 
enabled students to obtain a rather full knowledge of their struc- 
ture and habit. 
The Cordaites group is usually assumed to have become extinct 
at the close of the Paleozoic, but a Triassic genus known as Vuc- 
cites appears to represent a Mesozoic survivor, and other later 
coniferous groups such as the araucarias, ginkeos, and yews show 
significant resemblances to the Cordaites stock. 
Walchia, which appears in the geological record in the late Car- 
boniferous and is_ specially 
characteristic of the Permian, is a 
conifer of very modern appearance, and may possibly be an early 
representative of the Araucarian line. This supposition has been 
followed in depicting these trees, which are made to look exceed- 
ingly like a Chilean or Noriolk Island Pine, and they were certainly 
like them in habit of branching and general appearance. Walchia 
had spirally arranged, crowded, falcate, decurrent, needle leaves, 
and the foliage shoots bore terminal cones of two kinds—pollen- 
bearing and seed-bearing with single-seeded scales. The material 
is mostly in the form of impressions, and the structural details are 
not clear. 
At the right is a prostrate Baiera tree, and its characteristic 
