DISTRIBUTION" OF SEXES. 295 



develop imperfect flowers, which are liable to be mistaken at first sight for truly 

 hermaphrodite. They have plain well-developed ovaries, and stamens in whose 

 anthers pollen-grains are formed in greater or less numbers; but experiments with 

 this pollen have shown that when deposited on the stigma it emits no pollen-tubes, 

 and consequently the flowers are not in reality truly hermaphrodite, but only 

 apparently so. This is the case in some of the flowers in the panicle of the Horse 

 Chestnuts (jEsculus and Pavia), in some species of Dock (Rumex alpinus, obtusi- 

 folius, &c.), and in some of the flowers in the centre of the heads of the Colt's-foot, 

 Marigold, and Butter-bur (Tussilago, Calendula, Petasites). They appear herma- 

 phrodite although the ovaries never form fruits with fertile seeds, because their 

 stigmas are not capable of inciting the emission of pollen-tubes in the ripe pollen 

 deposited on them. Again, there are many plants where either the ovaries or the 

 stamens are so reduced that they can only be discovered by careful searching. 

 Some examples of the red Campion (Lychnis diurna) have flowers with well- 

 developed ovaries and stigmas, which are capable of fertilization, while their 

 stamens are extremely minute, consisting of triangular bodies scarcely 1 mm. long, 

 which bear a small polished head destitute of pollen instead of an anther. Other 

 plants of this same Campion bear flowers with ten stamens whose long ribbon-like 

 filaments are surmounted by large anthers with fertile pollen, but instead of the 

 ovary there is only a minute knob with two points indicating the stigma. 

 same thing occurs in the flowers of some Valerians (Valeria. dioica, simplicifol 

 &c.). The racemes of the Sycamore (Acer PteudoytatUMM) exhibit every imagin- 

 able gradation from pseudo-hermaphrodite male flowers, with comparatively large 

 ovaries, to those in which the ovaries are reduced or altogether absent. 

 mentioned these instances, to which many others might be added, to show \ 

 there is no lack of transitional forms between pseudo- hermaphrodite and 

 pistillate and staminate flowers; and again, in plants with neuter flowers espec, 

 in many species of the Grape-Hyacinth (Muscari), we have gradat.ons from t 

 hermaphrodite to neuter flowers. The remarkable structures known as gall- 

 (/. pp 159, 160) may also be mentioned here. They represent neuter 

 Icalnally undoubted links are found between ^^J"*"S 

 In spite of these transitional forms, which to some extent break down t 

 between the various kinds of flower, it is advisable to retam the names a ready 

 for the separate forms, since otherwise it would be unpo^ble to gwe a ger, 



content with dividing 



far 



^ 



We may place in the first group those plants whose species develop true herma- 



