台灣產蘭科斑葉蘭屬之分類研究

Abstract

本研究利用外部形態、細胞分類學及分子親緣學等研究資料，針對台灣產斑葉蘭屬（Goodyera）植物進行系統分類研究。 在外部形態方面，習性、葉部形態、花部的花萼瓣、蕊柱、傳粉體等特徵為區別台灣產斑葉蘭屬之重要特徵。 細胞分類學研究結果顯示不整倍體化（aneuploidization）與多倍體化（polyploidization）是本屬植物的特色，也是本屬植物演化及種化的重要機制。結果也顯示，在台灣本屬所有的20種植物染色體數可以分為三個大類群，第一群為2n= 22或42，第二群為2n=30或60，第三群為2n= 28或56。而染色體數歸群與形態外部性狀表現頗為一致，可供為種以上階層的分類依據。其中波密斑葉蘭、花格斑葉蘭、大武斑葉蘭、雙板斑葉蘭、南湖斑葉蘭、綠花斑葉蘭，小小斑葉蘭及南投斑葉蘭等8種的染色體數為首次報導。 分子親緣歸群樹狀圖結果可分為三大群六小群，而分子親緣研究結果顯示與本屬外表形態特徵相當一致，可提供分類的強力佐證。亦顯示台灣產的本屬植物為單系群。 過去Schlechhter將斑葉蘭屬植物分為二個節，本研究根據外部形態、細胞分類學及分子親緣學等研究結果，將本屬分為三個節分別為section I Goodyera斑葉蘭節，其植物體細胞染色體為2n= 30或60；section II Reticula S. W. Chung & C. H. Ou銀線蓮節，其植物體細胞染色體為2n= 28或56；section III Otosepalum Schlechter綠花斑葉蘭節，其植物體細胞染色體為2n= 22或42。 本研究確認台灣之斑葉蘭植物共20種，其中阿里山斑葉蘭G. arisanensis 及南投斑葉蘭 G. nantoensis是同物異名，其學名應為較早有效出版的南投斑葉蘭G. nantoensis；垂枝斑葉蘭G. pendula之學名改為G. recurva；短穗斑葉蘭G. maximowicziana 訂正為G. bifida；蘭嶼金銀草G. yamiana訂正為G. boninensis；小小斑葉蘭G. yangmeshanensis訂正為G. pusilla；歌綠懷蘭G. seikomontana為G. viridiflora的異名。而台灣原名為G. viridiflora的物種被誤鑑定，應改為G. carnea。而波密斑葉蘭G. bomiensis為新記錄種。台灣的斑葉蘭過去有6種為特有種，經過本研究確認台灣僅有4種 是特有種。

The taxonomical revision of the genus Goodyera, Orchidaceae, in Taiwan was made based on morphological, cytotaxonomic, and molecular phylogenetic studies. The members of this genus are morphologically diverse. Characters on leaves, sepals, petals, column and pollinaria, as well as habitat, are essential for intrageneric grouping.

The results obtained from study on the cytotaxonomy showed that aneuploidization and polyploidization exist in this genus, and they may play important roles on speciation in Goodyera. Based on cytotaxonomy, the Goodyera species in Taiwan can be divided into three groups. Mitotic chromosome numbers of these twenty species in Taiwan were observed in this research. The chromosome numbers for each group are 2n=22 or 42, 2n=30 or 60, and 2n=28 or 56 accordingly. Among these species, eight species were presented with the first study on cytotaxonomy. Molecular phylogeny showed that Goodyera in Taiwan was monophyletic and the taxa in Taiwan formed six clades.

The studies on morphology, cytotaxonomy, and molecular systematics are highly congruent to each other, and the new classification was made accordingly. The genus was divided into three sections: section Goodyera with chromosome numbers 2n=30 or 60, section Reticula Chung & Ou with chromosome numbers 2n=28 or 56, and section Otosepalum Schlechter with chromosome numbers 2n=22 or 42.

Twenty species were identified in Taiwan. Goodyera arisanensis, G. pendula, G. maximowicziana, G. yamiana and G. yangmeshanensis are synonymized under of G. nantoensis, G. recurva, G. bifida, G. boninensis and G. pusilla respectively. Goodyera viridiflora was mis-applied name correct name is G. carnea. Goodyera bomiensis was a new addition to the Flora of Taiwan.