Arisaema mengii Z.X.Ma, 2025

Ma, Zhengxu, 2025, Materia Revisionis Arisaemarum: III. taxonomic notes and five new taxa of the genus Arisaema (Araceae) from South China, Phytotaxa 697 (1), pp. 47-67 : 57-61

publication ID

https://doi.org/10.11646/phytotaxa.697.1.3

persistent identifier

https://treatment.plazi.org/id/EB2487C7-FFD3-FFAF-FF43-FB17FBEBF99E

treatment provided by

Felipe

scientific name

Arisaema mengii Z.X.Ma
status

 

5.1. Arisaema mengii Z.X.Ma , sp. nov. ( Figs. 8–9 View FIGURE 8 View FIGURE 9 )

Arisaema mengii is similar to A. calcareum H.Li View in CoL in Li et al. (1977: 106) but differs from the latter in having abaxially glaucous leaf blades, chartaceous when dry, a uniformly green spathe, without a white patch at back, broad lanceolate limb acute and uncaudate to the apex, widely auriculate spathe mouth, strongly reflexing on the back of limb, a thick claviform appendix, truncated stipitate at base. A. mengii is also reminiscent of A. sinii K. Krause (1930: 1047) View in CoL but differs from the latter in having chartaceous leaf blades when dry, an acute spathe limb, a broad auriculate spathe mouth strongly reflexing on the back of limb, a monoecious or male spadix with thick claviform appendix, truncated stipitate at base, without neuter attachment. A. mengii is also possibly related to A. xuanweiense H.Li (2000: 419) View in CoL , but differs in having a broadly and strongly reflexing auriculate spathe mouth, uniformly green spathe, and a robust, claviform spadix-appendix.

Type: — CHINA. Hunan Province: Yongzhou, Lanshan, Citangxu, Zhaitou, 24 April 2024, Z.X.Ma s.n. (holotype BAZI!, isotypes BAZI!, E!, PE!).

Perennial geophyte, seasonally dormant, paradioecious. Subterranean stem tuberous, greenish white, glabrous, subglobose, to ca. 4 cm in diam., rarely bearing tubercles, petiolar sheath breaking into persistent fibers during dormancy; accessory bud solitary, scattered. Eophyll unknown. Cataphylls 3, membranous, free at distal region (3.4– 4.1 cm), connate proximally. Foliage leaves 1–2 together; petiole pale green, proximally sheathing into an upright pseudostem, petiolar sheath connate proximally, free at apex, free part of petiole 17.6–31.6 cm long; leaf blade trifoliolate, green, abaxially paler, glaucous, thick membranous when fresh, chartaceous when dry; laminae venation broadly brochidodromous, strongly raised abaxially, slightly impressed adaxially, lateral veins forms brochidodromous collective venation near leaf edge; lateral leaflets subrhombic and somewhat oblique, 11.9–17.5 × 8.6–11.4 cm; central leaflet subrhombic, 7.8–16.5 × 11.1–11.3 cm, base sessile, broadly cuneate, apex acute. Inflorescence solitary, always 1 The isotype at K [barcode: K000499304] refers to a different species, A. consanguineum Schott (1859: 27) , and, as a heterogeneous entity, it must be excluded from the type gathering.

bearing on the pseudostem, below or equal with leaves in male, below than leaves in female. Peduncle pale green, glaucous, always proportionally longer in male than female. Spathe tube green, glossy, funnelform, attenuate to base, 4.8–5.6 cm long, 1.1–1.6 cm in diam. in the narrowest point; mouth green, broadly auriculate, to ca. 1.6 cm wide, strongly reflexing on the back of limb; limb green, glossy, bending forward and flat, long triangular to acute-ovate, 4.5–4.9 cm long, without a tail apically. Spadix male or monoecious when mature (female spadix not observed); monoecious spadix, pyramidoid, to 6.8 cm long; female zone, 1.0– 1.3 cm long, 0.6–0.7 cm in diam.; gynoecia densely arranged; ovary glossy green, obovoid, shaped, 1-locular; placentation basal; style very short; stigma white, puberulent; male zone with up to 14 synandria together; male spadix cylindric, to 6.4 cm long; androicea spirally arranged; synandrium consisting 2 bithecal anthers, cofiliment distinct; thecae dark purple, globose, dehiscing by a short slit resulting in an apical pore; appendix claviform, 5.4–5.8 cm long, base truncated stipitate, apex obtuse and swollen, to 1.1 cm in diam. Infructescence and seeds unknown. Anthesis from March to April.

Distribution: —NE Guangxi (Guilin, pers. comm. with D.C.Meng) to SW Hunan (Yongzhou), endemic to SW China.

Eponymy: —The species epithet “ mengii ” is in honor of De-Chang Meng (born 1996, South China Botanical Garden, Chinese Academy of Sciences), a passionate botanist, who provided the type material of this species.

Additional specimens examined (paratype): — CHINA. Yunnan: Mengzi, prepared from cultivated plants at Bazi Botanical Garden (originated from Yongzhou , Hunan), 19 June 2024, Y.E.Wang 637 (BAZI!) ; loc. ibid., 14 March 2025, Y.E.Wang 1729 (BAZI!) .

Notes: —The systematic position of Arisaema mengii remains a topic for imminent discussion.While its subglobose tuber, fully connate cataphyll and petiolar sheath, trifoliolate leaf blades ( Fig. 8 A, B View FIGURE 8 ), green spathe, and claviform and basally truncated stipitate spadix-appendix make it superficially reminiscent of A. sinii and A. calcareum , pro parte sensu typus ( Fig. 9 A–F View FIGURE 9 ), it is clearly distinct from both (see diagnosis).

When diagnosing against A. mengii above, the exact identity of Arisaema sinii is worth circumscription. A. sinii was first described by Krause (1930) based on type specimens of two duplicates collected by Shu Szi Sin (ỆŃffi, Ph.D. student of Berlin Botanical Garden during 1924–1927) in the Yaoshan Mountain Range of Northern Guangxi ( Fig. 10 A, B View FIGURE 10 ). Based on the types and protologue, the diagnostic characteristics of this species includes a green spathe with a slightly auriculate mouth, an acuminate and caudate limb apex, and a dioecious spadix with a cylindrical, sessile spadix-appendix bearing a few neuters or neuter residuals at the base ( Krause 1930, Fig. 11 A–G View FIGURE 11 ).

Furthermore, another enigmatic species, A. xuanweiense , possibly allied with A. mengii , also remains undetermined due to insufficient knowledge regarding its identity. A. xuanweiense was described based on a sole specimen and a line drawing from plant collected from Xuanwei, northeastern Yunnan, which was subsequently brought into cultivation in Li Heng’s nursery of the Kunming Botanical Garden (pers. comm. with Li Heng). Unfortunately, there is no known photographic record of the species, despite Li’s long-standing practice of photographing living materials.

According to the type specimen ( Fig. 12 A View FIGURE 12 ), A. xuanweiense is characterized by a tuber that likely being stoloniferous (though differently interpreted as rhizomatous in the protologue), trifoliolate leaf blade, an obliquely truncate spathe mouth without auricles, and a claviform spadix-appendix with a stipitate base (Li 2000). However, some features described in the original publication, such as a rhizome and details about the spathe form, seem inconsistent or misinterpreted based on the type specimen.

Making things more difficult, the line drawing accompanying the description of A. xuanweiense contains obvious mistakes, particularly the depiction of two protrusions on the underground stem which were originally labeled as new shoots (handwritten manuscript associated with the type specimen), but misinterpreted as an inflorescence in the final format ( Fig. 12 B View FIGURE 12 ), which is very uncommon in the Arisaema . In a recent interview, the artist revealed that he had never seen a living plant of A. xuanweiense during his preparation of the work, and the drawing was solely based on the holotype and Li’s description, where artistic interpretations may have not been accurate (pers. comm. with S.L.Tseng). Thus, unfortunately, given the lack of additional material and field observations from the type locality, the true identity of A. xuanweiense and its relationship with A. mengii remain unclear, though A. xuanweiense lacks an auriculate spathe and probably bears a stoloniferous tuber and is distinct from the new species A. mengii .

Kingdom

Plantae

Phylum

Tracheophyta

Class

Liliopsida

Order

Alismatales

Family

Araceae

Genus

Arisaema

Loc

Arisaema mengii Z.X.Ma

Ma, Zhengxu 2025
2025
Loc

Arisaema mengii

Z. X. Ma 2025
2025
Loc

A. mengii

Z. X. Ma 2025
2025
Loc

A. mengii

Z. X. Ma 2025
2025
Loc

A. xuanweiense H.Li (2000: 419)

H. Li 2000: 419
2000
Loc

A. sinii

K. Krause (1930: 1047: 1047
1047
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