PHANEROG AMIA, ‘998 
(0) Split a staminate and an ovule-bearing cone vertically, and 
study their structure, comparing the one with the other. Dissect 
out a stamen and an ovule-bearing scale, and compare. In the 
former note the pollen-sacs, and in the latter the ovules (Figs. 120 
and 122). ; 
(c) Study pollen-cells from young and mature staminate cones. In 
the young pollen look for the cells representing the first stage (pro- 
thallium); in the ripe pollen note the bladder-like enlargements of the 
outer coat (Fig. 121, B). 
(a) Note that the ovule-bearing cones of Scotch and Austrian pines 
are two years in coming to maturity. Make vertical sections of cones 
of various ages, and note the growth of the seed. Note the thin 
wing (useful in their dispersion) on the seeds. Make longitudinal 
sections.of seeds, and note the little plantlet with its several leaves 
(cotyledons). 
(e) Make cross-sections of leaves, and note the turpentine-canals, 
one near each angle, with others symmetrically arranged between. 
Make GCross-sections of the young twigs, and note the canals in the 
rind or bark. Make similar sections of the wood of the trunk, and 
note similar canals at intervals. 
(f) Make very thin cross-sections of the mature wood of the stem, 
and note shape and size of the cells; note also the gradual decrease 
in the size in passing from the inner to the outer side of a growth- 
ring. Now make a very thin longitudinal-radial section, and observe 
the bordered pits (Fig. 126). A longitudinal section at right angles 
to the last (longitudinal-tangential) will show no bordered pits. In 
all these sections note that the wood is made up of but one kind of 
cells, viz., tracheids, 
(g) In a cross-section of a stem, note the thin radiating plates of 
tissue (medullary rays), in many cases extending from pith to bark, 
In longitudinal-tangential section of the stem these rays are seen in 
cross-section to be made of thick-walled cells (stony tissue). In longi- 
tudinal-radial sections the rays are seen split lengthwise (Fig. 126, s/). 
(%) Make very thin cross-sections of the stem through bark and 
wood, and note the layers of very suft thin-walled tissue (cambium) 
between wood and bark. This may be made more evident by soak- 
ing the section for a few hours in carmine, by which the cambium 
will be stained. 
There are three orders of Gymnosperms, Viz.: 
472. The Cycads (Order Cycadacee) are large or small 
trees, with much the general appearance of the palms and 
