无叶莲科,缅甸被子植物一新记录科

近期在缅甸北部进行野外植物考察中,发现了一种菌类寄生植物,疏花无叶莲（Petrosavia sakurai）,是缅甸被子植物一新记录科和新记录目——无叶莲科和无叶莲目。对其进行了详细的报导,并提供特征描述等数据。疏花无叶莲主要特征为茎上的鳞片状叶较疏离且彼此相距1~2 cm、总状花序、花苞片稍短于花梗、花被约1/3贴生于子房上。     

Pollination biology of the saprophytic speciesPetrosavia sakuraii (Makino) van Steenis in Central Japan

Pollination biology of the saprophytic speciesPetrosavia sakuraii was investigated in Central Japan. The flower opens at any time of the day, and the anthers of outer stamens dehisce after about one day and those of the inner stamens after two days. The stigmata on the semicarpous (nearly apocarpous) pistil, which are already receptive when the flower opens, are situated in the center of the flower and move gradually outwards to touch the anthers of outer stamens about five days after anthesis. The breeding experiments show that the stigmata are receptive at least for five days, and many seeds are produced through autonomous self-pollination. That means the nearly apocarpous pistil, which is in a primitive condition, is adapted to the autonomous self-pollination. The selfing rate including insect-mediated self-pollination is very high, and this sexual-reproductive system seems favorable to the saprophytic plant which is probably severely limited in its resources. However, cross-pollination also may be performed by the small bees of Lasioglossum and some other insects, even though they do not so frequently visit the flowers and the out-crossing rate is low.     

A Phylogenetic Analysis of the Plastid matK Gene with Emphasis on Melanthiaceae sensu lato

Abstract: The presented mat K tree primarily agrees well with the previously presented rbc L tree and combined rbc L + atp B + 18SrDNA tree. According to the mat K tree, the monocotyledons are monophyletic with 100 % bootstrap support. Acorus diverges first from all other monocotyledons (90 % bootstrap support) in which two major clades are recognized: one (89 %) consisting of Alismatanae and Tofieldia (Nartheciaceae), and the other (< 50 %) comprising Lilianae, Commelinanae and Nartheciaceae other than Tofieldia. Within the latter major clade, Petrosavia and Japonolirion (Nartheciaceae) (82 %) diverge first from the remaining taxa (< 50 %) in which two clades are formed: one (81 %) consisting of Pandanales, Dioscoreales and Nartheciaceae-Narthecioideae, and the other (< 50 %) comprising Liliales, Asparagales and Commelinanae. In the former clade, Dioscoreales and Narthecioideae are grouped together (88 %). In the latter clade, Asparagales and Commelinanae are grouped together (< 50 %). Differences between the mat K and rbc L tree topologies appear in the positions of Tricyrtis (Calochortaceae) and Dracaenaceae. Differences between the mat K and combined rbc L + atp B + 18SrDNA tree topologies exist in the positions of the Petrosavia-Japonolirion pair (Nartheciaceae) and Pandanales. The stop codon position of the mat K gene appears to be highly variable among the monocotyledons, especially in the Liliales.