Endosperm with Lateral Haustoria
In Monochoria, in which the endosperm development is of helobial type, the haustorium is neither chalazal nor micropylar but lateral. The chalazal chamber does not grow further and contains only a few nuclei but the micropylar chamber shows active nuclear divisions ant develops two lateral outgrowths, one on either side of the chalazal chamber. These grow downwards and function as active haustoria invading the tissue of chalazal. Later, the main body of the endosperm enlarges considerably and fuses with the haustoria to form a compact mass of endosperm.
Figure: LS. Ovule of Monochoria showing endosperm with lateral haustoria