I shall first give an example from among the lower plants (Fig. 81). In one of the lichens, _Basidiobolus ranarum_, each of two adjacent cells in the fungus-thread gives off a bill-like process, and the two processes become closely apposed (Fig. 81, _a_). The nucleus of each cell moves into the bill-shaped process, is there transformed into a nuclear spindle (_B_, _ksp_) and divides, so that one daughter-nucleus comes to lie in the apex point of the bill, the other at the base. The cell-body also divides, though very unequally, and the final outcome of the process is two cells in each, of which one is small and occupies the apex of the bill, while the other is large and fills all the rest of the cell-space. The former do not play any further part of importance, but break up, the latter are the sex-cells, the cytoplasm of which now coalesces through a gap in the cell-walls, while their nuclei become closely apposed and ultimately unite (_C_, ♂ and ♀ _k_). From this union arises the fertilized spore, the so-called 'zygote' (_D_). The two small abortive cells so greatly resemble in their origin the polar cells of the animal ovum that it is difficult to resist the supposition that they bring about a reduction in the number of chromosomes. But the number of the chromosomes has not yet been determined either in them or in the sex-nuclei. [Illustration: FIG. 81. Formation of polar bodies in a lichen, _Basidiobolus ranarum_. _A_, the two conjugating cells with the bill-like processes in which the nuclei lie. _B_, the nuclei dividing. _ksp_, the nuclear spindle. _C_, after the division into a polar body (_rk_) and a sex-nucleus (♂ _k_ and ♀ _k_). _D_, after the union of the nuclei to form a conjugation nucleus (_copk_); the fertilized ovum is surrounded by envelopes and modified into a lasting spore. After Fairchild.] We have come to know the processes of fertilization among phanerogams chiefly through Strasburger, Guignard, and more recently through the Japanese botanist Hirase. The agreement with the animal process is surprisingly great, notwithstanding the notable differences in the external conditions of fertilization. As is well known, the male cells in the highest flowering plants are not zoosperms but roundish cells, each of which, enclosed, together with a sister-cell--the so-called 'vegetative' cell--in a thick cellulose capsule constitutes a pollen-grain. The pollen-grains reach the stigma, under which, buried deep within the 'ovule,' the female sex-cell rests, enclosed in a long, sac-like structure called the 'embryo-sac' (Fig. 82, _A_). Beside it (_eiz_) there lie several other cells, usually seven in number, two of which, the so-called 'synergidæ' (_sy_), have their place at one end of the embryo-sac, just in front of the ovum (_eiz_). Probably these give off a secretion which exercises an attractive (chemotactic) influence on the male fertilizing body ('the pollen-tube'), and thus, so to speak, show it the way to the ovum.