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NOTES ON THE DEVELOPMENT OF THE OVULE, EMBRYO 
SAC AND EMBRYO OF HYDNORA AFRICAN A, THUNB. 
By R. H. Dastur, B.Sc.Bombay, F.L.S. 
(With thirteen Text-figures.) 
Introductory. 
The genus Hydnora is confined to South Africa, Bourbon and Madagascar, 
and comprises several species, out of which three only occur in South Africa. 
They are all parasites, and the species which forms the subject of these notes, 
viz. Hydnora Africana, uses mainly the common milkbush of the karoo, 
Euphorbia mauritanica, L., as its host, and is of fairly common occurrence in 
South Africa (3). The flowers appear as buds on the underground stem, but 
soon come above the surface of the ground, and open when mature by means 
of three longitudinal slits. 
The material for this investigation was collected in the neighbourhood 
of Worcester, Cape Province, mostly by Prof. Saxton in December, 1912, 
and in part by Mr. Izak Meiring in May, 1912, and fixed in chromacetic acid 
with or without osmic acid. A short series of sections was prepared by 
Prof. Saxton, but pressure of other work prevented him from completing the 
series, and in November, 1919, he handed over the whole material to me. 
The fixed material consisted mainly of small pieces of the extensive placentas 
cut out from a series of about a dozen plants ranging from the youngest to 
the oldest that could be found. 
Investigation. 
The placentas are extensive and much branched, and bear radially 
enormous numbers of orthotropous ovules. The sections were cut, in the 
main, transverse to the longitudinal axis of the placentas, thus giving 
longitudinal sections of the ovules in great numbers. A very young ovule 
before the differentiation of the integument is shown in Fig. 1. Very soon 
a massive integument makes its appearance, at the top of which the cells 
divide by periclinal walls giving rise to four layers of cells, while it is only 
two cells thick on the sides. The very young ovules are nearly spherical 
but elongate afterwards. No definite archesporial cell or cells are clearly 
