ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
617 
and impregnate one of the antipodals. To this phenomenon the author 
applies the term homceogamy. 
Embryogeny of Sequoia.* — Mr. W. R. Shaw describes the develop- 
ment of the male and female flowers in Sequoia sempsrvirens. The 
integument of the young megasporange consists of the inner and outer 
epiderm and two layers of liypodermal cells. When the flower closes, 
the integument is about twice as long as the sporange. The micropyle 
then begins to close, enclosing the pollen-grain in a subconical cavity. 
The gradual development of the sporogenous cells in the megasporange 
is described in detail ; each produces four megaspores. These at once 
begin to develope female prothallia. A number of embryo-sacs are 
produced, each containing many nuclei. The archegones are numerous, 
and are usually arranged radially on the upper half or third of the pro- 
thallium. The central part of the upper half of the prothallium bears 
several intertwined tubular suspensors, each with an 8- or 12-celled 
embryo. 
At the time when the pollen is shed, each grain consists of two cells 
— a larger vegetative cell with a large nucleus, and a smaller lenticular 
parietal cell with a smaller nucleus. The vegetative nucleus passes 
into the pollen-tube. The pollen-tube branches and penetrates the wall 
of the sporange at several paints at a considerable distance from the 
micropyle, presenting therefore, in this respect, a resemblance to the 
chalazogamous Angiosperms. 
Fertilisation of Loranthacese.j — Mr. F. W. Keeble states that the 
Cingalese species of Loranthacese which have tubular flowers are orn:- 
thophilous, the bird most effective in their pollination being a honey- 
sucker {Nectar inia). In the large-flowered species, especially in Loran- 
thus loniceroides, the flower-buds remain closed ; but when tapped, the 
corolla-lobes fly open with an explosion, and the pollen is scattered. 
The closing of the flower-buds appears to serve the purpose of protecting 
the pollen against rain ; while the violent expulsion of the pollen aids in 
its carriage by the visiting birds, their beaks being frequently found to 
be covered with pollen after visiting the flowers. In many species the 
corolla is slit longitudinally, and the anthers are then placed in a row 
behind the style, instead of in a ring round it ; and this greatly facilitates 
the carriage of the pollen by birds in search of the nectar. 
Homology of the Pollen and Ovule. :f — From observations made 
largely on abnormal structures in Torilis Anthriscus and Sinapis arvensis , 
M. M. Molliard supports Celakovsky’s conclusion that the anther corre- 
sponds to a simple leaf, the limb of which is doubled on each side of the 
median vein, each part giving rise to a mass of pollen ; but the two 
halves are not of equal value ; one contains the median fibrovascular 
bundle, while the other is an emergence of the first, and contains only 
very small bundles. 
The study of a number of cases of transformation of stamens into 
carpels ( Sedum , Petunia , Narcissus, &c.) has led the author to the con- 
clusion that the entire pollen-mass of an anther is the homologue of a 
* Bot. Gazette, xxi. (1806) pp. 332-9 (l pi.). 
t Trans. Linn. Soc. (Bot.), v. (1896) pp. 91-6 (2 pis. and 2 figs.). 
X Rev. Gen. de Bot. (Bonnier), via. (1896) pp. 273-83 (19 figs.). 
2 y 2 
