452 SPERMATOPHYTES (SEED PLANTS) 
Sporophyte. — The sporophytes of the Pines are mostly large 
and in some cases are of huge dimensions. Some species of Pine 
attain a height of 150 feet or more. It is characteristic of Pine 
trees to have a main trunk and comparatively small lateral 
branches. The main branches are usually in clusters, and in 
some Pines, unless closely inspected, one might mistake the 
branches to be in whorls. There is a gradual reduction in length 
of branches from below up- 
ward, so that trees grown 
in the open have a conical 
shape (Fig. 400.) 
The needle-like leaves 
are usually borne in groups 
or fascicles of two, three, 
or five leaves according to 
the species. The duration 
of leaves varies according 
to the species and condi- 
tions, but Pines shed only 
a part of their leaves at a 
time and hence are always 
green. 
Strobili. — The strobili, 
as in the Cycads, are of 
two kinds — staminate and 
ovulate (Fig. 401). The 
staminate and ovulate 
strobili occur separately, 
on the same trees, or on 
different, trees. 
The staminate strobili or 
cones (Fig. 402) are pro- 
duced in clusters and in the Northern states may be seen in May or 
early June. They vary in size in different species, sometimes at- 
taining a length of half an inch or more, but in many species they 
are much smaller. They expand from the buds in a few days, 
soon shed their pollen and disappear, usually persisting only a few 
weeks. A microstrobilus is, in reality, a modified branch con- 
sisting of a main axis bearing scale-like microsporophylls or 
stamens, which are arranged spirally and closely crowded. On 
= 7/) 
1 ey, Fa 
Fic. 401.— A branch of a Pine, show- 
ing an ovulate strobilus at a and a cluster 
of staminate strobili at b. 
