Equisetum yongpingense A.T.Aung, T.Su & Z.K. Zhou, 2020

Aung, Aye Thida, Huang, Jian, Do, Truong Van, Song, Ai, Liu, Jia, Zhou, Zhe-Kun & Su, Tao, 2020, Three new fossil records of Equisetum (Equisetaceae) from the Neogene of south-western China and northern Vietnam, PhytoKeys 138, pp. 3-15 : 3

Equisetum yongpingense A.T.Aung, T.Su & Z.K. Zhou sp. nov.

Holotype.

XTBGYP0748 (Fig. 3A ).

Paratypes.

XTBGYP0747 (Fig. 3B ), XTBGYP1014 (Fig. 3C ), XTBGYP1015 (Fig. 3D ), XTBGYP0750 (Fig. 3E ), XTBGYP0749 (Fig. 3F ).

Locality.

Sanying Formation, Longmen Village, Yongping County, western Yunnan Province, south-western China (25.518N, 99.519E).

Age.

The late Pliocene.

Repository.

Paleoecology Collections, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences.

Etymology.

The species name ' yongpingense ' means that fossils are from Yongping County, south-western China.

Diagnosis.

Rhizomes with internodes and round nodes; fibrous roots on most nodes; two to four bunches of tubers arranged in a whorl on a node (Fig. 3A ); tubers cylindrical in shape, one to two tubers on each bunch (Fig. 3A-B ); longitudinal ridges not observed on the surface of tuber; the tip of tuber mucronate (Fig. 3A ).

Description.

Rhizomes have both internodes and nodes (Fig. 3A ). The internode is ~0.5 to 0.8 cm wide, the length is up to 5.1 cm (Fig. 3A ). The node is round and ~0.7 to 1.0 cm in diameter (Fig. 3A-B ). Most nodes have fibrous roots ~ 0.1 to 0.2 cm wide. Two to six bunches of tubers attach on one node and are arranged in a whorl (Fig. 3A-B ). One to two tubers are preserved on each bunch (Fig. 3A-B ). Tubers are cylindrical, ~ 1.5 to 3.4 cm long and 0.6 to 1.2 cm wide (Fig. 3A-F ). Ridges were not observed on the surface of each tuber (Fig. 3A-B, E ). The tip of tuber is mucronate (Fig. 3A ).

Figures

Figure 3. Equisetum yongpingense A. T. Aung, T. Su & Z. K. Zhou, sp. nov. Specimen numbers: A XTBGYP 0748 B XTBGYP 0747 C XTBGYP 1014 D XTBGYP 1015 E XTBGYP 0750 F XTBGYP 0749. Scale bars: 1 cm.