to receive any—this occurs in Wahlenbergia, Gentiana, etc., and such flowers are functionally unisexual, and are said to be proterandrous. But all have not this character so fully developed, and every gradation may be noticed from complete proterandry to the opposite extreme. Thus in buttercups, the outer anthers commence to dehisce first, and the process extends from without inwards; but considerably before the inner anthers have dehisced the stigmas have become viscid. In Epilobium again, at least among New Zealand species, I have never been able to notice any difference of time between the maturing of the anthers and stigmas. Here cross-fertilization, when it takes place, will be chiefly accomplished through the prepotency of the pollen brought from other flowers by insect visitants. But this functional separation of the sexes is equally well accomplished by the opposite arrangement, viz., the maturing of the stigmas first, and the protrusion and dehiscence of the anthers only after the former have been pollinated and are withered up. This is very well exemplified in the various species of Coriaria (tutu). Such flowers are called proterogynous, while the term dichogamy is applied generally to the maturing of the sexual whorls at different times. Another means of accomplishing the same end, viz., cross-fertilization, is attained by the occurrence of two or more forms of flowers in the same species (heterostylism.) Thus some species of Primula are dimorphic, having two forms, one with long style and short stamens, the other with short style and long stamens. Some few flowers are even trimorphic. For a more complete description of these forms I must refer to Darwin's work already quoted. I have not detected distinct heterostylism in any New Zealand plant as yet, though in some Pimeleas, Asperula, etc., I have found something very like it. Special structures of the perianth, or of the sexual whorls, serve to prevent self-fertilization among certain flowers, and to ensure their proper pollination, but these are so numerous and varied as to obtain only a passing notice here. I have detailed in the body of this paper the most conspicuous of these modes, as they are exemplified among New Zealand plants. It is worthy of notice that entomophilous plants are usually furnished with flowers possessing, more or less markedly, the following characters:—(1.) Conspicuous appearance, attained in a variety of ways, viz., by individual size as in Clematis indivisa; aggregation into more or less dense clusters as in Rubus australis, and many of the Compositæ, etc.; or, brilliancy of colour as in our iron-wood, (Metrosideros lucida). (2) Fragrance. (3) Honey. Sometimes all three characteristics are present, as in certain of the wild roses of Europe, but as a general rule a principle of economy prevails, so that if any one attraction is present to a great extent, the others are usually wanting. Thus Clematis indivisa has very conspicuous flowers, but they