Zingiber
Creators: name: Lin, Yuan-Chien
name: Chao, Chien-Ti
name: Chang, Chih-Yi
name: Tseng, Yen-Hsueh
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Liliopsida
Zingiberales
Zingiberaceae
Zingiber

description: Characters of Zingiber from Taiwan
We examined and compared several characters of species of Zingiber from Taiwan, and those that were shown to have taxonomic value are listed in Table 1.
Habit
The Taiwanese taxa of Zingiber can be classified into two types, evergreen (Z. pleiostachyum and Z. shuanglongense) and deciduous (Z. chengii, Z. mioga, and Z. oligophyllum).
Rhizome
The cross sectional color of the rhizome varies from purple in Z. shuanglongense to yellow in other taxa (Fig. 1).
Ligule
The ligule is bilobed except in Z. oligophyllum, in which it is reduced (Fig. 2).
Inflorescence
The number of flowers per inflorescence and the shape of the bract, including the bracteole, are diagnostic characters. Zingiber chengii has only one to three loosely arranged flowers in an inflorescence. The other taxa all have more than three flowers that are densely arranged. The fertile bracts are usually narrowly ovate except in Z. oligophyllum where they are broadly ovate (Fig. 3).
Flowers
Floral characters are often regarded as diagnostic by several scholars (Wu & Larsen 2000; Yeh et al. 2012, 2013; Bai et al. 2016; Ohba 2016), and we found that to be true for the classification and identification of Taiwanese Zingiber. Each character is listed and described below.
Corolla tube
Two colors of corolla tube are classified here, creamy-white and yellow. Zingiber chengii and Z. shuanglongense have creamy-white corolla tubes, while Z. mioga, Z. oligophyllum, and Z. pleiostachyum have yellow corolla tubes.
Labellum
The labella can be separated according to color into purple and yellow. Zingiber chengii and Z. shuanglongense have obovate to widely ovate, bluish-purple labella with creamy-white patches on the basal parts. In contrast, Z. pleiostachyum has an obovate to oblong, reddish-purple labellum with yellow patches on the basal parts (Fig. 4). For the yellow type, Z. mioga and Z. oligophyllum have ovate to widely ovate, yellowish labella without patches.
Lateral staminodes
The morphology of lateral staminodes is similar to the labella; however, the dimensions of the adnate part could be of some taxonomic significance. For Z. pleiostachyum, the adnate part is ½ to ⅔ of the size of the staminodes, while all others often have adnate parts that are only ⅓ to ¼ the size of the staminodes.
Anther crest
Stamen morphology also provides taxonomic value for the Zingiber of Taiwan. The anther crest can be distinguished by color. The purple variety includes Z. chengii, Z. shuanglongense, and Z. pleiostachyum, while Z. mioga and Z. oligophyllum represent the yellow color.
Distribution pattern of taxa of Zingiber of Taiwan
Zingiber of Taiwan are often found in shady areas with high humidity, such as beneath the forest canopy, at forest margins, and in deep valleys. In terms of vertical distribution, the highest altitude habitat was found for Z. shuanglongense, which grows at heights up to 1600 m in the south (Fig. 5). Zingiber pleiostachyum is the most widely distributed species in Taiwan, found across the island and Lanyu Island (Fig. 6); in contrast, Z. chengii and Z. mioga are restricted to a very narrow area in Hsinchu and Ilan counties, respectively (Figs 5, 7). Zingiber shuanglongense and Z. oligophyllum are found in the central to southern parts of Taiwan (Fig. 7).
Haplotype network and genetic distance of Zingiber koshunense, Z. pleiostachyum, and Z. shuanglongense
In order to clarify the relationship of taxa with similar morphology, i.e., Z. koshunense, Z. pleiostachyum, and Z. shuanglongense, we reconstructed a haplotype network of these taxa. Two groups emerged from the haplotype network analysis: Z. pleiostachyum and Z. shuanglongense, with nine and four haplotypes, respectively. No shared haplotypes were found between the two groups. The haplotype of a specimen of Z. koshunense from Lanyu Island was identical to that of Z. pleiostachyum (Fig. 8).
The genetic distance of Z. pleiostachyum vs Z. shuanglongense and Z. koshunense vs Z. shuanglongense was 0.0113, and that of Z. koshunense vs Z. pleiostachyum was 0.0005. These results revealed that Z. koshunense was more close to Z. pleiostachyum than to Z. shuanglongense, which was similar to the pattern of haplotype network analysis (Table 2).
Key to the species of Zingiber from Taiwan
1. Labellum yellowish .......................................................................................................................... 2
– Labellum violet or reddish ................................................................................................................ 3
2. Ligules reduced, truncate, <1 mm long; leaf upper surface plicate ......... Z. oligophyllum K.Schum.
– Ligules bilobed,> 1 mm long; leaf upper surface smooth ........................ Z. mioga (Thunb.) Roscoe
3. Spike with only few sterile bracts; capsule ovoid; ⅓ of seed enveloped by the aril ......................... ...................................................................................... Z. chengii Y.H.Tseng, C.M.Wang & Y.C.Lin
– Spike with several sterile bracts; capsule ellipsoid; ¾ of seed enveloped by the aril ...................... 4
4. Corolla tube yellow; ½ to ⅔ of lateral staminodes connate to labellum; capsule longer than the persistent bract ....................................................................................... Z. pleiostachyum K.Schum.
– Corolla tube creamy-white; ⅓ to ¼ of lateral staminodes connate to labellum; capsule equal to or shorter than the persistent bract ...................................... Z. shuanglongense C.L.Yeh & S.W.Chung
description: Published as part of Lin, Yuan-Chien, Chao, Chien-Ti, Chang, Chih-Yi & Tseng, Yen-Hsueh, 2022, Taxonomic revision of Zingiber (Zingiberaceae) of Taiwan, pp. 74-102 in European Journal of Taxonomy 839 on pages 76-83, DOI: 10.5852/ejt.2022.839.1933, http://zenodo.org/record/7119107