220 
MORPHOLOGY 
Taxodineae (8 genera and about 1 5 species), including the characteris- 
tic American genera Sequoia (redwood) and Taxodium (bald cypress), 
FIG. 486. Transverse section of a pine needle, showing the epidermis (in which are 
deeply sunken stomata) underlaid by several layers of heavy-walled cells (sclerenchyma), 
the mesophyll with characteristic infolded walls and containing resin ducts, the distinct 
bundle sheath (endodermis) surrounding the vascular region (stele), and the two parallel 
vascular bundles (xylem directed towards the flat face of the leaf). 
Cupressineae (9 genera and about 80 species), including the cypress, 
arbor vitae (false cedar), and junipers, the large genus being Juniperus, 
with about 30 species. This tribe is 
peculiar among Coniferales in its opposite 
(cyclic) leaves. 
Araucarineae (2 genera and about 20 
species), known as araucarians or arau- 
carian pines, and characteristic of the 
southern hemisphere. 
Sporophyte. The general habit of the 
sporophyte body is sufficiently indicated 
by the familiar forms mentioned above 
(also see fig. 955). The vascular cylinder, 
487, 488. Staminate with its endarch bundles, its thick cylinder 
cone (487) and microsporophylis o f secondary wood composed of radially 
(488) of pine (the latter in two , .. . , . , , . 
views), showing the two abaxial arranged tracheids with bordered pits, is 
sporangia and the sterile tip. well known (fig. 485). So far as known, 
FIGS. 
