Parahellenia candida (Škorničk., Böhmová & H.Ð.Trẫn) N.H.Xia & Juan Chen

Chen, Juan, Nguyen, Van Canh, Nguyen, Van Khuong, Nguyen, Khang Sinh, Nuraliev, Maxim S. & Xia, Nianhe, 2023, Taxonomic studies on Parahellenia (Costaceae) in Vietnam: a new species, P. trongduyii, and a new combination, P. candida, Phytotaxa 583 (1), pp. 72-80 : 73

Parahellenia candida (Škorničk., Böhmová & H.Ð.Trẫn) N.H.Xia & Juan Chen , comb. nov.

Basionym:— Cheilocostus candidus Leong-Škorničková, Böhmová & Trẫn (2022: 105) .

Type:— VIETNAM. Lam Dong Province (cultivated in the Singapore Botanic Gardens, Singapore), collected from cultivation on 21 September 2021, Leong-Škorničková GRC-421 (holotype SING; isotypes E, P, SGN) .

Phenology:—Flowering in the natural habitat was observed in June; in cultivation, it extends to October; fruiting unknown.

Distribution, habitat and conservation:—Endemic to Vietnam, occurring near rocky streams in lowland broadleaved evergreen forest, at elevations about 200– 300 m. According to Leong-Škorničková et al. (2022), there is no reliable information on the population sizes or distribution of this species. It was therefore treated as Data Deficient ( IUCN 2012).

Notes:— Parahellenia candida is characterized by unbranched or barely branched stems, radical inflorescence, long and narrow floral tube fused with the style base more than halfway (assessed from Fig. 2 in Leong-Škorničková et al. 2022) and bilamellate stigma. With these features, this species fits well the concept of the genus Parahellenia .

Parahellenia candida is very similar to P. tonkinensis in producing the inflorescence radically, obovate to elliptic leaf blades and bract apex with a sharp mucro, but can be distinguished easily from the latter by its unbranched or barely branched leafy shoots, densely puberulent leaf sheaths, densely puberulous abaxial side of leaf blade and white flowers ( Leong-Škorničková et al. 2022).

Figures

FIGURE 2. Parahellenia trongduyii: vegetative morphology. A, B. Habit. C. Rhizome and leafy shoot. D, E. Nodes with leaf sheaths and petioles. F. Node with bud. G. Rhizome and a terminal bud. Photos by V.C. Nguyen from the type V.C. Nguyen & V.K. Nguyen CD 01.