HOMEOSIS IN THE FLOWERS OF THE ZINGIBERALES

Homeosis has played an important role in the evolution of the flowers of the Zingiberales, especially those of the Ginger Group. In the Zingiberaceae, two members of the outer androecial whorl are replaced by a lip, and two members of the inner androecial whorl are replaced by petaloid staminodes. Most of the androecium of the Costaceae has also been replaced by petaloid structures, and the single fertile stamen is often attached to an enlarged petaloid “filament.” The Cannaceae and Marantaceae have one-half of one fertile anther and three to four variously modified staminodes. In contrast, homeosis has played a minor role in floral evolution of the Banana Group. Only in the Heliconiaceae has a stamen been replaced by a staminode. In none of the families of the Zingiberales do the staminodes assume the total “form or character” of any perianth members. Because of this, it is reasonable to extend the definition of homeosis to include replacement by an organ like, but not identical to, some other part of the plant.     

THE MORPHOLOGY OF THE MYRISTICACEAE. I. FLOWERS OF MYRISTICA FRAGRANS AND M. MALABARICA

Floral histology and vascular anatomy of Myristica fragrans Van Houtt. and M. malabarica Lam. have been investigated from serial sections and specimens cleared in chloro-lacto-phenol. The flowers are unisexual. The androecium is considered to consist of a whorl of laterally concrescent anthers. The bisporangiate anthers are attached by a ridge of tissue to the terminal part of the androphore. In many cases the number of vascular bundles in the androphore is half the number of anthers. The gynoecium consists of a monocarpellate pistil with basal placentation and a single anatropous ovule. Of the many vascular bundles that enter the base of the carpel, two, because of their position and because they provide vascular traces to the ovule, are designated as ventral bundles. Additional ovular traces are provided by the carpel wall vascular system. These additional traces originate at the top of the locule and descend to the ovule. The similarity between the androecia of these two species and the androecium of the ćnellaceae is noted.     

被子植物的花化石研究

五十多年前胡骕在研究山东临朐县山旺组的植物化石中,发现有花的化石,仅保存了5个花瓣或仅5个萼片,均难给予确切的分类位置;六十年代我们两次去山旺野外工作,发现为数较多,同样仅保存花瓣或萼片的化石。本文研究的是80年代发现并保存较为完好的花化石。新近李凤麟详细论述了各门类化石,均认为山旺组的地质时代属中中新世。近十余年来,国际上被子植物的花化石的研究进展较快。每次花化石的发现,对研究被子植物种系发生、系统位置及在地史中的演化及演变速率等均是极重要     

ULTRASTRUCTURAL DEVELOPMENT OF THE BEETLE FOOD TISSUE OF CALYCANTHUS FLOWERS

The flower of Calycanthus traps a wide variety of beetles which, while imprisoned, effect pollination. During their occupancy the insects eat a protein-rich tissue developed at the tips of the inner tepals, stamens, and staminodia. Cells of this food tissue differentiate a large number of cytoplasmic protein tubules by using a protein vacuole as an assembly site. The cells comprising the food tissue represent a very specialized plant cell type and one which facilitates this particular plant/insect relationship.