212 BOTANICAL GAZETTE : [APRIL 
flowers and immersed ovaries. The form is interesting in being dioecious, 
monoecious, or ‘‘monoeciously polygamous.’’ The development 0 
sporangiate structures is of the usual angiospermous type. It is noteworthy 
that 100 or more antipodals appear and persist in the seed, although they con- 
tain little reserve food, which occurs chiefly in the starchy perisperm. 
Chief attention, however, is given to the extreme variability in the devel- 
opment of sporogenous tissue as shown by different spikes or by different 
flowers of the same spike. e number of microsporangia produced by a 
stamen may vary from none to four, and the extent of a sporangium is widely 
variable. The point is made that these differences are not determined during 
the course of development, but are constant from the time of the initiation 
of the sporogenous tissue. Space relations in the spike hold no relation to the 
differences, for any condition may develop at any region of the spike. All 
that the author can suggest is that “the real cause is probably to be sought 
in those factors, internal or external, that disturb the normal production oF 
course of movement of material in the plant.’ 
Incidentally, the author concludes “that the tissue of the young spike, 
and often of the individual flower, must be hermaphrodite in character,” 
_ since the differentiation of the two kinds of sporogenous tissue, involving the 
subsequent development of the two kinds of sexual tissue, “must take place 
at or after the initiation of the rudiments of the parts of the flower.” —J. M. C. 
Philippine forests.—Wurtrorn’s continued investigations in the Phil 
pine forests are making us better acquainted with tropical vegetation in com- 
parison with the more familiar vegetation of the United States and Europe. 
A recent paper gives a detailed account of the forests dominated by members 
of the Dipterocarpaceae, a family whose name has to most of us an unfamiliar 
sound, though in the Philippines it is even more important than are pines and 
oaks with us, since it makes up 75 per cent of the virgin forest area;” of the 
9,000 square miles of Philippine virgin forest, 30,000 square miles are dom- 
inated by dipterocarps. From the lumberman’s point of view the diptero- 
carps may be divided into three categories: those which yield hard and durable 
timber; those which yield a timber comparable to that of our hard pines} and 
those whose timber qualities resemble those of our soft pines. Dipteroc@ 
timber compares favorably as to commercial value with the more familiar 
timbers of Europe and the United States. While some forests of temperate — 
regions surpass those of the Philippines in the matter of bulk, the latter perhaps 
equal any temperate forests when the amount of the annual increme? I) 
taken into account together with the bulk. The best forests are found where 
climatic, edaphic, and biotic factors are at their optimum. Obvious growth 
rings occur in some trees, but are lacking or obscure in others; as yet it is not 
= Wurtrorp, H. N., Studies in the vegetation of the Philippines. 1. The ee 
position and volume of the dipterocarp forests of the Philippines. Phil. Jour. 9% 
4°699-725. pls. 7. 1909. 
