ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
437 
Abortive or Transformed Sexual Organs.* — Herr J. Familler Las 
traced the biogenesis of reduced sexual organs in a number of plants, 
and gives the following as the more important general conclusions. 
The repression or transformation of the organ in question may go back 
to very different stages in different plants, or even in different flowers 
of the same plant. In the case of the male organs the most common 
cases are: — an arrest of the primordial stage with a small development 
of filament ; and the appearance of divisions which would lead normally 
to the formation of an anther-wall, without a true archespore being 
developed. In arrested female organs the embryo-sac is usually, but not 
always, formed, but the formation of the integuments is very feeble. 
In flowers with numerous stamens and staminodes, the passage from 
one to the other is gradual. If pollen is formed in an arrested stamen, 
it is the number and not the size of the pollen-grains that undergoes 
reduction. Filiform staminodes, such as those of Pentstemon , correspond 
not to the filament alone, but to the anther as well. A staminode may 
be actually transformed into a nectary or secreting organ in the course 
of its development. 
Proterandry in a Palm.f — M. J. Daveau records a remarkable 
instance of proterandry ■ in a species of Kentia ( Hoivea ). The small 
flowers are grouped in clusters within the spadix. Each cluster consists 
of three flowers, two male and one female ; but the female flowers are 
only in a very rudimentary condition even after the male flowers are 
fully matured and have dropped. They remain in this condition through 
the autumn and winter, and only expand at. the same period in the next 
summer, when the male flowers in other newly formed inflorescences are 
discharging their pollen. 
Biology of Pollen. J — Herr B. Lidforss points out that the statement 
that the immense majority of pollen-cells perish in water, and that even 
contact with water is very injurious, is much too wide. The closing of 
flowers in wet weather does not effect a protection of the anthers against 
rain to the extent that is often assumed, since it affords no defence 
against sudden and heavy rain. The capacity of different pollen-grains 
to resist the injurious action of water differs very widely, even in plants 
nearly related to one another. Many pollen-grains will germinate well 
in distilled water, while the addition of even a very small percentage of 
a mineral salt will arrest the power of germination ; in some cases the 
addition of even 0*01 per cent, of potassium or calcium nitrate will have 
this effect. The addition of an acid will, on the other hand, often 
promote germination ; and this may, in some cases, be induced by 
placing the stigma in the water. In a large number of plants the 
stigma and anthers are entirely unprotected from rain, and this is 
especially the case with anemophilous plants. In these instances the 
pollen generally displays a great resistancy against moisture. The 
pollen-grains of anemophilous plants almost invariably contain starch. 
Formation of Pollen within Ovules. § — Among other changes, M. 
M. Molliard finds the formation of pollen within the ovule to be not 
* Flora, lxxxii. (1S96) pp. 133-68 (10 figs.). 
t Journ. de Bot. (Morot), x. (1896) pp. 25-6. 
X Jahrb. f. wiss. Bot. (Pfeffer u. Strasburger), xxix. (1896) pp. 1-38. 
§ Rev. Gen. de Bot. (Bonnier), viii. (1896) pp. 49-58 (1 pi.). 
1896 2 H 
