Typhonium khonkaenensis A.Galloway & Seth Charoenwong

Van, Hong Thien, Le, Van Son, Nguyen-Phi, Nga, Nguyen, Quoc Dat, Nguyen, Tran Quoc Trung, Nguyen, Hieu Cuong & Luu, Hong Truong, 2021, A new species and a new record of Typhonium (Araceae) from southern Vietnam, Phytotaxa 527 (3), pp. 201-208 : 204-206

Typhonium khonkaenensis A.Galloway & Seth Charoenwong in Galloway (2015: 11) ( Fig. 3 )

Type: — THAILAND. Type: from a plant cultivated by A. Galloway (orig. coll.: Khon Kaen Province, in sandy soil in open sunny areas, S. Charoenwong ), 4 July 2014, Galloway AGA-2513-01- T (holotype QBG, spirit collection) .

Herb seasonally dormant; rhizome cylindrical, underground, 1.5–3.0 cm high, 2.0– 2.5 cm in diameter, producing many filiform roots. Leaves 3–5. Petiole smooth, slender, 6–12 cm, 2–3 mm in diameter, green to pale grey, smooth. Leaf blade variable, entire to 3-lobed; entire blade 7–14 cm long, 1–4 cm wide, green above, pale green beneath, base cordate, apex acute, midrib slightly impressed adaxially and prominent abaxially, lateral veins 2–3, collective veins at 1–2 mm from margin; lobes linear-lanceolate to ovate or elliptic, sometimes petiolulate, apex acute to acuminate, central lobe 3–16 cm long, 0.5–2.0 cm wide, lateral lobes 3–6 cm long, 0.5–1.0 cm wide. Inflorescence 1–2, strongly foetid smelling; peduncle subterranean, white, slender, 3–4 cm long, ca. 5 mm in diameter; spathe 8–14 cm long, basal part subterranean, separated from the limb by a constriction, ovoid or ellipsoid, 1.5–1.8 cm long, 0.8–1.2 cm wide, white on both sides, sometimes purple tinged externally; spathe limb linear-lanceolate, 11–13 cm long, ca. 1 cm in diameter at base, curved downward at anthesis, outside grey to dark purple, brownish mottled, inside dark violet, with or without white longitudinal stripes at base; spadix longer than spathe, 17–20 cm long, stipitate, stipe 1.5–2.0 mm long; female zone hemispherical to conical, 1.5–2.5 mm high, 2.5–4.0 mm in diameter at base, with 4–5 rows of crowded pistils; ovary cylindrical to obconical, 0.5–0.7 mm high, 0.5–0.6 mm in diameter, light yellow, 1-locular, with 1 basal ovule; stigma sessile, 0.3 mm in diameter, concave, sometimes papillose at center, pale yellow with purple around, many pale reddish mottles surrounded stigma; sterile interstice above female zone, about 1.5 cm long, lower part 1–2 mm from female zone covered with 2–3 rows of staminodes, upper and lower part naked; staminodes loosely arranged, lightly brown, fusiform, 3–5 mm long, 0.5–1.0 mm in diameter, ascending, apex obtuse to subacute; male zone cylindrical, 3–4 mm long, 4 mm in diameter; stamens densely arranged, translucent; thecae light yellow, opening by elongate slit, pollen orange to yellow; appendix stipitate, light yellow to greenish brown, filiform, 15–18 cm, 2–3 mm in diameter at base, base slightly swollen, stipe ca. 2 mm long, acute, white. Infructescence obconical with spathe tube persistent; fruits obconical, apex truncate or concave, cream white, pinkish white with pale reddish spots, sometimes apically green with purple dots, 3–4 mm long, 1.5–2.5 mm wide, 1-seeded; seed obovate cream white or pale pinkish, 2.5–3.5 mm long, 1.5–2.0 mm wide.

Specimens studied: — VIETNAM. Ho Chi Minh City, 29 May 2017, Thong Nhat Palace, Luu Hong Truong H . T . Van 83 C ( SGN!) ; Long An Province, Duc Hoa District , 06 Aug 2015, Nguyen Phi Nga H . T . Van 83 B ( SGN!, PHH!) ; Ba Ria - Vung Tau Province, Binh Chau - Phuoc Buu Nature Reserve , about 107 o 30’27’’E, 10 o 33’01’’N, 32 m elevation, 06 June 2015, Van Hong Thien H . T . Van 83 A ( SGN!, PHH!) .

Notes: —Our collections show that the populations from inland (i.e., Ho Chi Minh City and Long An Province) match well the protologue of T. khonkaenensis but that from the coastal Ba Ria - Vung Tau Province is quite distinction in having highly variable shapes of leaf blade (such as triangular, cordate-sagittate, linear-lanceolate or trifoliolate). The leaf blade of Typhonium is often known to vary within one species and a genetic analysis may help explain if this relates to any genetical differentiation among populations of T. khonkaenensis in Vietnam.

Typhonium violifolium was first described as a new species from Thailand (under the name “ T. violaefolium ”) by Gagnepain (1942a: 1177) but the name was validly published by his subsequent publication ( Gagnepain 1942b: 12). The species was then reported by Pham-Hoang (1970) to occur in Saigon (Ho Chi Minh City presently). This report was followed in his subsequent updates (1993 and 2000) and other later Typhonium -revising publications (e.g. Nguyen & Vu 2004, Nguyen 2017, Van 2017). All these reports did not include any vouchered specimens. Nguyen (2017) even noted that he tried but failed to find the species in Vietnam. We have recently found at the herbarium PHH a specimen named as Typhonium sp. (with code PHH0004167) collected by Pham-Hoang from Thong Nhat Road, Saigon in September 1964. This specimen well matches his same illustration in 1970, 1993 and 2000. Our examination of the specimen indicates that it is indeed a specimen of T. khonkaenensis . According to Gagnepain (1942), Sriboonma et al. (1994) and Boyce et al. (2012), T. violifolium has a reniform to ovate leaf blade, a short petiole (ca. 6 cm long); pale green or whitish spathe that is nearly as long as spadix, short and white staminodes and a short appendix (ca. 7 cm long). On the contrary, the description by Galloway (2015) and our collections of T. khonkaenensis show that this species has highly variable leaf blades, longer petiole (6–12 cm long), abaxially brownish mottled, dark violet and abaxially grey to dark purple spathe that is much shorter than spadix, long and light brown staminodes and long appendix (15–18 cm). In fact, both Sriboonma et al. (1994) and Boyce et al. (2012) did not note any distribution of T. violifolium in Vietnam. In addition, T. violifolium grows in mixed evergreen forest on limestone while T. khonkaenensis does in open sandy soils. Therefore, it is reasonable to exclude T. violifolium from the flora of Vietnam.

Figures

FIGURE 3. Typhonium khonkaenensis. A. The species in habitat. B. Whole plant. C. Different forms of leaf blade. D. Inflorescence. E. Spathe. F. Part of spadix showing male, sterile and female zones. G. Spathe, inside. H. Stamens. I. Female flowers. J. Fruits. K. Seeds.