The Mystery of Sex, or Sex Polarity

...fertilized by its own pollen.' A few years later, in 1799, Andrew Knight argued that no hermaphrodite flower a flower containing both male and female reproductive organs fertilizes itself for an endless number of generations. Sprengel's discovery of the 'secret of nature' had, however, to be presented again by Charles Darwin. In his books The Fertilization of Orchids (1862) and The Effects of Cross- and Self-Fertilization (1876), Darwin not only used a great wealth of illustrations to show the various devices plants use to ensure insects unknowingly carry fertilizing pollen from one flower to another, but he also emphasized the advantages of cross-fertilization original: "cross-fertilization," the process of fertilization between two different individual plants for the overall health of the species. 'Nature tells us,' Darwin says, 'in the most emphatic manner that she abhors perpetual self-fertilization.'

Scientists such as Hildebrand, Hermann Müller, Delpino, and others have, with great patience and observation, further uncovered these natural secrets. For more information, the student may refer to D'Arcy Thompson's valuable edition of Müller's The Fertilization of Flowers, Sir John Lubbock's Flowers in Relation to Insects, the classic works of Darwin, and P. Knuth's Handbook of Flower Biology original: "Handbuch der Blütenbiologie," 2 vols., Leipzig, 1892.

However, we must also mention the objections of Thomas Meehan, who argued that self-fertilization is neither as rare nor as 'hateful' to nature as is generally believed. In many cases, cross-fertilization by insects does occur; in many others, it must occur. In another significant group of flowering plants—usually those with small, unremarkable blossoms—the fertilizing 'gold dust' is carried by the wind and falls upon neighboring flowers like the legendary 'golden shower' that fell upon Danae In Greek mythology, the god Zeus visited the princess Danae in the form of a shower of gold. In many hermaphrodite flowers, self-fertilization certainly does take place; in some, this is necessarily the case. Unquestionable self-fertilization occurs in the small, underdeveloped flowers that never open—known as cleistogamous flowers that stay closed and self-pollinate, typically near the ground flowers—found in plants such as certain species of balsam, dead-nettle, pansy, and others. These grow alongside regular flowers and, curiously enough, are sometimes more fertile than the open ones."

Another authority says: "Fertilization is the fecundation the act of making a plant fertile or productive of a plant by applying pollen to the stigma the part of the flower's female organ that receives pollen. In some cases, the pollen simply drops onto the stigma, which is called self-fertilization. In most instances, however, it is blown by the wind, or...