Zingiber

Lin, Yuan-Chien, Chao, Chien-Ti, Chang, Chih-Yi & Tseng, Yen-Hsueh, 2022, Taxonomic revision of Zingiber (Zingiberaceae) of Taiwan, European Journal of Taxonomy 839, pp. 74-102 : 76-83

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

Figures

Fig. 1. Rhizome cross sections. A. Zingiber shuanglongense C.L.Yeh & S.W.Chung (Aluwan historical trail, Y.C. Lin 1342 (TCF)). B. Other taxa, represented by Z. pleiostachyum K.Schum. (Chichidashan, Y.C. Lin 1290 (TCF)). Photos: L.P. Hsu. Scale bars = 1 cm.

Fig. 2. Ligules. A. Zingiber oligophyllum K.Schum. (Chading Trail, Y.C. Lin 1161 (TCF)) B. Other taxa, represented by Z. pleiostachyum K.Schum. (Mihu Trail, Y.C. Lin 1151 (TCF)). Photos: L.P. Hsu.

Fig. 3. Bracts and bracteoles. A. Zingiber oligophyllum K.Schum. (Chading Trail, Y.C. Lin 1161 (TCF)). B. Other taxa, represented by Z. plaeiostachyum (Mihu Trail, Y.C. Lin 1151 (TCF). Photos: L.P. Hsu. Scale bars = 1 cm.

Fig. 4. Labellum of Zingiber Mill. of Taiwan. A. Z. shuanglongense C.L.Yeh & S.W.Chung (Shuanglung Logging Trail, Y.C. Lin 1294 (TCF)).B. Z. pleiostachyum K.Schum. (Chichidashan, Y.C. Lin 1290 (TCF)). C. Z. chengii Y.H.Tseng, C.M.Wang & Y.C.Lin (Jianshih Township, Y.C. Lin 1148 (TCF)). D. Z. mioga Thunb. (Ying Ziling roadside, Y.C. Lin 1366 (TCF)). E. Z. oligophyllum K.Schum. (Chading Trail, Y.C. Lin 1161 (TCF). Photos: L.P. Hsu. Scale bars = 1 cm.

Fig. 5. Distribution map ofZingiber chengii Y.H.Tseng, C.M.Wang & Y.C.Lin (star) andZ. shuanglongense C.L.Yeh & S.W.Chung (dots) in Taiwan.

Fig. 6. Distribution map of Zingiber pleiostachyum K.Schum. in Taiwan.

Fig. 7. Distribution map of Zingiber mioga Thunb. (star) and Z. oligophyllum K.Schum. (dots) in Taiwan.

Fig. 8. Haplotype network of Zingiber koshunense C.T.Moo, Z. pleiostachyum K.Schum., and Z. shuanglongense C.L.Yeh & S.W.Chung reconstructed by three cpDNA regions. Each circle represents a haplotype, circle size represents different population sizes of such haplotype. The arrow indicates the haplotype which included samples of Z. koshunense C.T.Moo.

Tables

Table 1. Morphological comparisons of species of Zingiber Mill. of Taiwan.

	Z. chengii	Z. shuanglongense	Z. pleiostachyum	Z. mioga	Z. oligophyllum
Rhizome (internally)	yellow	dark violet	yellow	light yellow	yellow
Leafy	spreading to	erect, or slightly	erect, or slightly	erect, or slightly	erect, or slightly
shoots	weakly arching,	inclined,	inclined,	inclined,	inclined,
	11–15 leaves	7–21 leaves	6–21 leaves	11–16 leaves	6–13 leaves
Lamina	linear-lanceolate to lanceolate, 9–15 × 1.5–2.5 cm	narrowly oblong to lanceolate, 12–23 × 2–7 cm	narrowly oblong, 12–29 × 3–8.5 cm	narrowly oblong, 13–29 × 4–7 cm	narrowly obovate, 26–37 × 8–11 cm
Lamina
length /	ca 6	ca 3.7	ca 3.8	ca 4.4	ca 3.8
width ratio
Corolla tube	creamy-white, ca 3.5 cm	creamy-white, ca 3.0 cm	yellow, ca 3.6 cm	yellow, ca 2.5 cm	yellow, ca 2.7 cm
Labellum	widely obovate, ca 3.0 × 2.5 cm, apex retuse or entire	widely obovate, ca 2.9 ×1.9 cm, apex retuse or cleft	obovate or elliptic, ca 2.8 ×1.1 cm, apex retuse,	widely obovate, ca 2.8 × 2.0 cm, apex retuse or entire	narrowly ovate, ca 1.7 × 0.5 cm, apex incised or entire
Lateral	narrowly oblong,	narrowly oblong,	narrowly oblong,	narrowly oblong,	narrowly oblong
staminodes	ca 2.0 × 0.5 cm,	ca 2.3 × 0.4 cm,	ca 1.6 × 0.5 cm,	ca 1.6 × 0.5 cm,	to spathulate, ca
	connate to	conlabellum at basal	connate to	labellum at basal	connate to	labellum at basal	connate to	labellum at basal	1.1 × 0.3 cm, conlabellum at basal labellum at basal labellum at basal labellum at basal nate to labellum	nate to labellum
	conlabellum at basal	labellum at basal	labellum at basal	labellum at basal	nate to labellum
	⅓ to ¼	⅓ to ¼	½ to ⅔	ca ⅓	at basal ca ⅓
Color of labellum and lateral staminodes	violet, scattered with cream- white patches at base	violet, scattered with cream-white patches at base	red or deep violet, yellow patches at base	yellow	yellow
Fruit	ovate	elliptic	elliptic	elliptic	elliptic
Seed
enveloped	⅓	¾	¾	¾	¾
by the aril

Table 2. Genetic distance between Zingiber koshunense C.T.Moo, Z. pleiostachyum K.Schum, and Z. shuanglongense C.L.Yeh & S.W.Chung.

Taxa set	Genetic distance (SE)
Z. koshunense vs Z. pleiostachyum	0.000458 (0.000286)
Z. koshunense vs Z. shuanglongense	0.011299 (0.002247)
Z. pleiostachyum vs Z. shuanglongense	0.011311 (0.002246)