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Bulletin of Botanical Research ›› 1985, Vol. 5 ›› Issue (3): 109-120.

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A STUDY ON THE TWO TYPES OF FLOWERS IN SCHNABELIA OLIGOPHYLLA HANDEL-MAZZETTI

Su Song-wang   

  1. Department of Biologv, Anhui University, Hefei, Anhui
  • Online:1985-09-15 Published:2016-06-13

Abstract: C. Chein (1964) discovered for the first time the two types of flowers, chasmogamous and cleistogamous in genus Schnabelia. Based on the materials available, he then pointed out that the problem whether the two types of flowers of the genus Schnabelia existed on the same individual plants or on the different individuals still remained unclear, and that they seemed to be on the different plants. The present research in to S. oligophylla Hand.Mazz.collected from Qimen of Anhui Province make it distinct that the two types of flowers undoubtedly exist on the same plant.So far as the time of their appearance is concerned, the chas-mogamous flowers precede the cleistogamous ones. As for their positions, they situated themelves separately on their own cy-mes, and come out of the leaf axils above the near base, at the same time the cleistogamous ones do out the lowest base of the chasmogamous flower's peduncle after these flowers wi-thering. The occurrence of the cleistogamous flowers probably has something to do with the inf1uence of the environmen-tal factors. Having transplanted some S. oligophylla from the growing area to Hefei, the author observed after potting it, that the flowers which came out in the year were chasmogamous, while the flowers that appeared early next year were chas-mogamous, and then came out the cleistogamous ones. As for manner of fertilization, a cleistogamous flower is ob-viously that of self-fertilization. The chasmogamous flowers, rich in colour, is suited to entomophilous pollination, but the surface of their anthers is covered with sparse arachnoid hairs. At the time when the alabustrum is just about flower, the top parts of the filaments incurved and the anthers con-tact with one another laterally to form a ring, through which the style just pierces when it extends. Nevertheless, the arachnoid hairs on the surface of the anthers adhere to the branchlets of the style. After flowering, the stamens and the style begin to stretch straight. From this phenomenon may be seen that the chasmogamous flowers probably have the self-fertilization capability, which, when the cross-pol-lination fails ensures the work of self-fertilization. It should be particularly pointed out that having studied the two types of flowers of the genus Schnabelia, the present writer discovered that the two types of flowers of Caryopteris nepetaefolia and Scutillaria indica have quite the same structure as those of the genus Schnabelia too. In the species with the two types of flowers, the manners of fertilization of flowers are altogether differently. Generaly the conspicusous flowers (chasmogamous) are cross-fertilization and cleistogmous only adapt to self-fertilization. It is shown that this genetic system is unprofitable to the populations of cleistogamous of which the two types of flowers exist on the different plants, which finally will lead to completely homo-zygous and become a single biotype consisting of genetically similar individuals. For the species of the two types of flo-wer, on the same individual plant, the genetic system may be better than above one, because such plants not only produce a great many seeds which are the result of self-fertilization, but may also form a favourable gene combination following inter-racial hybridization of chasmogamous. But the author found that interracial hybridization in chasmogamous of S. oligophyl-la appears difficult because of the arachnoid haris on surface of their anthers, which alaways adhere to the branchlets of the style, so the self-fertilization is compelled to facilitate. It is shown that there are some shortages in the chasmogamous of S. oligophylla.