Micromorphology of the labellum and floral spur of Cryptocentrum Benth. and Sepalosaccus Schltr. (Maxillariinae: Orchidaceae)

Background and Aims: Gross vegetative and floral morphology, as well as modern moleculartechniques, indicate that Cryptocentrum Benth. and SepalosaccusSchltr. are related to Maxillaria Ruiz & Pav. However, theydiffer from Maxillaria in their possession of floral spurs and,in this respect, are atypical of Maxillariinae. The labellarmicromorphology of Maxillaria, unlike that of the other twogenera, has been extensively studied. In the present report,the labellar micromorphology of Cryptocentrum and Sepalosaccusis compared with that of Maxillaria and, for the first time,the micromorphology of the floral spur as found in Maxillariinaeis described. Methods: Labella and dissected floral spurs of Cryptocentrum and Sepalosaccuswere examined using light microscopy (LM) and scanning electronmicroscopy (SEM). Key Results: In each case, the labellum consists of a papillose mid-lobe(epichile), a cymbiform region (hypochile) and, proximally,a spur, which is pronounced in Cryptocentrum but short and bluntin Sepalosaccus. The inner epidermal surface of the spur ofCryptocentrum is glabrous or pubescent, and the bicellular hairs,where present, are unlike any hitherto described for Maxillariinae.Similar but unicellular hairs also occur in the floral spurof Sepalosaccus, whereas the glabrous epidermis lining the spurof C. peruvianum contains putative nectar pores. Conclusions: The labellar micromorphology of Cryptocentrum and Sepalosaccusgenerally resembles that of Maxillaria. The floral spur of Cryptocentrumdisplays two types of organization in that the epidermal liningmay be glabrous (possibly with nectar pores) or pubescent. Thismay have taxonomic significance and perhaps reflects physiologicaldifferences relating to nectar secretion. The trichomes foundwithin the spurs of Cryptocentrum and Sepalosaccus more closelyresemble the hairs of certain unrelated, nectariferous orchidtaxa than those found in the largely nectarless genus Maxillaria,and this further supports the case for parallelism.     

斯勒卷瓣兰，中国云南南部兰科一新种（英文）

描述并绘制了云南南部兰科石豆兰属一新种：斯勒卷瓣兰(Bulbophyllum dresslerianum Z. D. Han & H. Wang)。该新种属于双叶卷瓣兰组(section Tripudianthes Seidenf.),在形态上与该组的4种,即狄氏卷瓣兰(B. dickasonii)、堪布里石豆兰(B. kanburiense)、皱掌卷瓣兰(B. rugosisepalum)和拟双叶卷瓣兰(B. tripudians)近似,主要区别在于该种唇瓣前缘具囊泡,侧面及腹面被稀疏的短腺毛;侧萼片棕黄色,表面光滑。编制了斯勒卷瓣兰及其近缘种的检索表。目前,该种仅在云南南部墨江县发现一个居群,濒危状况有待评估。     

姜花(Hedychium coronarium)花部维管束系统解剖学研究

姜花(Hedychium coronarium Koen.)花梗横切面整体轮廓呈椭圆形,可分为表皮、基本组织和维管束。维管束在基本组织中呈内、外两部分排列。内部维管束联结成网,形成明显外移的三束心皮背束和内方与心皮背束相间的三束隔膜束。至子房室区,心皮背束继续外移,其中主支进入花萼中脉;小分支内移,与内方一轮维管束联结,后来进入唇瓣中央及2枚侧生附属物。在花萼形成的同时,远轴面的两个隔膜中各形成一个上位腺体;同时两束远轴面隔膜束向外、两侧分别形成3束大分支,外方大分支继续外移成为2枚远轴面花瓣中脉,两侧大分支与原外方内移的子房壁维管束集合成一相连的环状维管束网,后进入唇瓣两侧;近轴面隔膜束形成3枚分支,外方分支成为近轴面花瓣中脉,两侧分支进入可育雄蕊。探讨了侧生附属物和唇瓣的来源,支持子房延长部形成的腺体为隔膜蜜腺的变异结构的观点。