Development of the Ovule, Embryo Sac and Embryo of Hydnora africana. 31 
tion of earlier stages was undertaken to test the point. So far as can be 
ascertained, however, it seems clear that no parietal cell is formed at all. 
The long filament of cells produced by transverse divisions from the 
fertilised egg is unusual among Dicotyledons though paralleled in certain 
Leguminosae (2). Generally the formation of the embryo proper takes 
place in the distal cell of the proembryo amongst flowering plants, but in 
this plant it is approximately in the fifth, sixth, seventh, eighth and ninth 
cells from the distal cell that the formation of the embryo proceeds. So 
there are three regions in the proembryo : (1) the suspensor, (2) the embryo 
proper, and (3) the cells beyond the embryo. The most mature embryo 
observed (Fig. 13) is still undifferentiated, and the material available does 
not admit of the investigation of later stages, but field observations indicate 
that probably these would only be met with in germinating seeds. A small 
embryo in which neither radicle nor cotyledons are differentiated has been 
described for a number of parasitic and saprophytic Dicotyledons, but none 
of them shows an embryo of precisely the same type observed and figured 
for Hydnora. In Engler and Prantl's ' Pflanzenfamilien' (1) there is figured 
a mature embryo of ProsojJanche Burmeisteri, De Bary (the only genus 
allied to Hydnora), but the latter does not appear to show the peculiar 
features described here for Hydnora, so far as such features are shown iu 
Solms' figure cited. 
In conclusion I have to thank Prof. Saxton for advice, suggestions and 
criticisms on various points in this investigation. Thanks are also due to 
Mr. Izak Meiring for his help in the collection of material. 
Summary. 
(1) The ovule of Hydnora is orthotropous with a single integument. 
(2) The megaspore mother-cell is hypodermal and becomes the embryo sac. 
(3) The proembryo consists of a row of about fifteen cells. 
(4) The embryo is produced from the middle region of the proembryo, 
and no differentiation had taken place in the latest stages seen (probably 
from nearly ripe seeds). 
Note.— This investigation was carried out in the Botanical Laboratory 
of the Madhavlal Eanchhodlal Science Institute, Ahmedabad. 
Literature Cited. 
(1) Solms, H. Graf zu. — " Rafflesiaceae " and " Hydnoraceae " in Engler and Prantl, 
' Pflanzenfamilien/ III Teil. Ab. 1, 1889. 
(2) GtUIGNard, L. — " Recherches d'embryogenie vegetale Comparee. I: Legnmineuses," 
1881. (In Coulter and Chamberlain's 'Morphology of Angiosperms.') 
(3) Maeloth, R. — " Notes on the Morphology and Biology of Hydnora africana," 
'Trans. S. Afr. Philos. Soc./ vol. xvi, Part v, 1907. 
(4) Coulter and Chamberlain. — 'Morphology of Angiosperms/ 1912. 
