AMORPHOPHALLUS BANTAE
ORIGINAL DESCRIPTION:
Amorphophallus bantae J.T.Scholten, D.W.Livingston & Sizemore, sp. nov. (Figs. 1, 2)
Similar to Amorphophallus tenuistylis in general morphology and habit, but differs by having an overall smaller inflorescence, elliptic spathe with vertical stripes and a mucronate limb apex (rather than a lanceolate unstriped spathe with an acute apex), a spadix as long or slightly shorter than the spathe (in contrast to a spadix distinctly longer than the spathe), and congested pistillate flowers with shorter (ca. 1 mm long) styles (as opposed to sparsely arranged pistillate flowers with long (3–4 mm) styles).
Type:—UNITED STATES OF AMERICA. Florida, Fort Myers, from a plant cultivated by D.W.Livingston from the collection of John Banta, 28 Apr. 2023, Justin Scholten 366 (orig. living coll.: THAILAND. Sa Kaeo Province, North of Ta Phraya District, 125 m, N14°7’21.23” E102°40’33.48, 15 Oct. 2000 (holotype BH!)
SYNONYMS:
HOMOTYPIC SYNONYMS: N/A
HETEROTYPIC SYNONYMS: N/A
ACCEPTED INFRASPECIFICS: N/A
DISTRIBUTION: Thailand | Known only from this type locality in the Ta Phraya district of Sa Kaeo province, Thailand
CLIMATE: The province of Sa Kaeo experiences a seasonal tropical climate with the rainy season typically lasting from May through October, dry season from November through January, and summer from February through April. The mean annual air temperature in Sa Kaeo is among the highest of the provinces in this region, averaging 28.4° C, while the average humidity and rainfall is among the lowest, 74.5% and 1404 mm respectively (Phattraporn et al. 2016).
ECOLOGY: Sa Kaeo comprises an approximate area of 7,200 square kilometers in southeastern Thailand and is geographically diverse, with both flat plains in the south and the Khao Ban Thad mountains in the north (ranging in elevation from 74 m and 740 m respectively). The mountainous region in the northern sector of the province gives origin to the Bang Pakong River, an ecologically important watershed within the province (Chaikongthong et al. 2015). The type locality for this species occurs in an open lowland valley between the Khao Sakae Krong (480 m) and Khao Thing Kap (305 m) mountains at an approximate elevation of 100–150 m.
SPECIES DESCRIPTION:
Tuber napiform to elongate, 5–8 cm long, 3–5 cm diam. Petiole 25–32 cm long, 0.8–1.2 cm diam, surface glabrous, green with numerous vertical whitish/light green stripes. Lamina 41–46 cm diam, rachises narrowly winged proximally and distally; leaflets ovate to elongate elliptical, 22–32 cm long, 24–28 cm wide; foliolules ovate to lanceolate, adaxial surface slightly darker green than abaxial surface, collective vein distant from margin, 32–40 foliolules per leaflet.
INFLORESCENCE:
Inflorescence solitary; peduncle 28–34 cm long, 6–9 mm in diam at the base, glabrous, with purple vertical stripes grading to green, 0.25–2.00 mm in diam, and whitish ovoid mottles, ca. 0.25 mm in diam. Spathe elliptical-cuneate, 14–16 cm long, 2.5–3.5 cm in diam, erect, base and limb separated by a shallow constriction, exterior dark green with purplish vertical stripes, 0.25–2 mm in diam, and whitish ovoid mottles, 0.25 mm in diam (as peduncle), limb interior as exterior but without stripes or mottles, base interior light purple/red and distinctly verrucose. Spadix sessile, as long or slightly shorter than spathe, 13–15 cm long; pistillate zone cylindric, 2–3 cm long, 0.75–1.25 cm diam, pistils crowded; staminate zone cylindric, 5–6 cm long, 0.75–1.25 cm diam, stamens crowded; appendix cylindric, 5.5–6.5 cm long, 0.4–0.6 cm diam, purplish-brown, glabrous toward apex, slightly corrugated at base, apex mucronate, emitting a vague citrus-like odor at anthesis. Ovaries depressed-globose, 1.8–2.1 mm diam, 1.2–1.4 mm long, light green, 2–3-locular; style ca. 1 mm long, slightly angulate, purple; stigma depressed, 1.2–1.4 mm diam, 0.2–0.3 mm high, 2–3 lobed, surface covered densely in fleshy projections, yellow to pale brown. Male flowers consisting of 2–6 stamens, lowermost stamens slightly enlarged, 2–5 mm long, 2–5 mm diam; filaments ca. 1 mm long, up to 2mm long in lowermost flowers; anthers reddish-purple, 1.5–2.5 mm long, 1.25–2 mm diam, connective slightly depressed, pores apical, elongate. Fruits not observed.
VARIEGATED FORMS: N/A
ETYMOLOGY: The epithet of this species honors John Banta, a superb plantsman, for his contribution to Araceae conservation and discovery of this species.
NOTES:
Amorphophallus bantae shares some degree of morphological similarity with all members of the Longituberosus and Saraburiensis subclades within the subgenus Scutandrium, including having an elongate tuber, medium inflorescence size, spathe base interior with elongate papillae, spathe base and limb being separated by little to no constriction, emission of citrus-like odor from the appendix at anthesis, stigmas with pronounced styles, and elongate thecae pores. It differs from Amorphophallus saraburiensis and Amorphophallus scutatus in not having sterile synandrodes present between the pistillate and staminate zone and a spadix that is as long or shorter than the spathe (versus distinctly longer)—important diagnostic characters in the genus. Amorphophallus bantae can be easily distinguished from Amorphophallus tenuispadix and Amorphophallus albispathus in having a striped spathe and peduncle, reddish appendix, and purple styles. Although similar to Amorphophallus longituberosus in having a striped spathe and peduncle, short spadix, and 3-locular ovary, Amorphophallus bantae can be discriminated by the presence of a reddish appendix, purple styles, and depressed ovaries.
Other specimens examined (paratypes):
UNITED STATES OF AMERICA. Florida, Fort Myers, from a plant cultivated by D.W.Livingston from the collection of John Banta, 13 June 2023, Justin Scholten 425. From same plant as Justin Scholten 366 (type) (orig. living coll.: THAILAND. Sa Kaeo Province, North of Ta Phraya District, 125 m, N14°7’21.23” E102°40’33.48, 15 Oct. 2000 (paratype BH!); Florida, Fort Myers, from a plant cultivated by D.W.Livingston from the collection of John Banta, 28 July 2023, Justin Scholten 455. From same plant as Justin Scholten 366 (type) and Justin Scholten 425 (paratype) (orig. living coll.: THAILAND. Sa Kaeo Province, North of Ta Phraya District, 125 m, N14°7’21.23” E102°40’33.48, 15 Oct. 2000 (paratype BH!). The combination of a striped spathe with little to no constriction separating the base and limb, spadix as long or shorter than the spathe, reddish appendix, elongate thecae pores, congested green ovaries, and 2–3-lobed stigmas with purple styles distinguish Amorphophallus bantae from all other species in the genus. It should be noted that some species in this group (i.e., Amorphophallus longituberosus and Amorphophallus tenuispadix) can be quite variable in morphology. The variation among individuals of Amorphophallus tenuispadix can be so severe, that certain forms may be indistinguishable from Amorphophallus albispathus aside from the number of ovary locules. The observed variation within the characters expressed by Amorphophallus bantae does not seem to encroach the morphological species boundary of any taxon in either subclade, reinforcing its status as a species nova. It should be noted however that Amorphophallus bantae was described from a small ex-situ population and morphological variation may be higher in wild populations not observed. Future molecular analyses aimed at discriminating genetic variation within and between subclades should be pointed here.
Amorphophallus tenuistylis perhaps shares the closest morphological affinity with Amorphophallus bantae, both species share a mottled peduncle and spathe, reddish appendix, purplish spathe base interior with pronounced warts, 2–3-lobed stigma, and reddish-purple style; however, Amorphophallus bantae has an overall smaller inflorescence, elliptic spathe with vertical stripes and a mucronate limb apex, a spadix as long or slightly shorter than the spathe, and congested pistillate flowers with shorter (ca. 1mm long) styles
| Trait | Amorphophallus bantae | Amorphophallus tenuistylis | Amorphophallus longituberosus | Amorphophallus albispadix | Amorphophallus tenuispadix |
|---|---|---|---|---|---|
| Peduncle length | 28–34 cm | 64–88 cm | 10–76 cm | 20–40 cm | 11–29 cm |
| Peduncle exterior | light green with purple vertical stripes and small whitish mottles | olive green with small grayish mottles | gray or light pink with green or brown mottles and (often) dark vertical stripes | uniformly pink or olive-green grading up to pink | light brown to pinkish with few to many dark elongate mottles |
| Spadix length | 13–15 cm | 24–48 cm | 5.0–15.5 cm | 8–13 cm | 5.5–12.0 cm |
| Spadix–spathe ratio | spadix as long or shorter than spathe | spadix longer than spathe | spadix as long or shorter than spathe | spadix shorter than spathe | spadix as long or shorter than spathe |
| Appendix size | 5.5–6.5 cm long, as broad or narrower than staminate zone | 16–30 cm long, as broad or narrower than staminate zone | 2.5–8.0 cm long, as broad or broader than staminate zone, never narrower | 2–8 cm long, much broader than staminate zone | 1.5–4.0 cm long, much broader than staminate zone |
| Appendix color | purplish-brown | reddish-purple | whitish-beige | whitish-beige | whitish-beige |
| Spathe length | 14–16 cm | 19–40 cm | 5–20 cm | 6–14 cm | 5–13 cm |
| Spathe shape | elliptic | lanceolate | elliptic to elongate triangular | triangular–ovate | elliptic to lanceolate |
| Spathe limb apex | mucronate | acute or acuminate | acute or acuminate | acute or acuminate | acute or acuminate |
| Spathe exterior | uniformly dark green with purplish vertical stripes and small whitish ovoid mottles | limb reddish-brown with small dark mottles; base grayish-green with small gray mottles | uniformly light green or gray with or without large brownish-green mottles or vertical stripes | uniformly greenish-white or pinkish-white, occasionally grading to darker pink toward base | greenish-gray or pinkish gray (rarely white) with or without large dark ovoid mottles |
| Spathe interior | limb uniformly dark green; base reddish-brown with elongate warts | limb uniformly reddish-brown; base dark purple with long, (often branched) warts; ovaries 1–4 mm apart | limb uniformly light green or gray; base as limb or reddish with small elongate warts | as exterior or paler with small elongate warts | as exterior or paler, base typically without mottles and loosely verrucose |
| Pistillate flower density | congested | scattered | congested | congested | congested |
| Ovaries | 2–3-locular | 3-locular | 3-locular | 3–4-locular | 1-locular |
| Stigma shape | depressed; 2–3 lobed | hemispheric; 3-lobed | flattened; 3–4 lobed | flattened; 3–4 lobed or bilabiate | discoid; bilabiate |
| Stigma color | dark yellow to pale brown | bright yellow | bright yellow | white or yellow | white or yellow |
| Style length | ca. 1 mm | 3–4 mm | ca. 1 mm | ca. 1 mm | ca. 1 mm |
| Style color | reddish-purple | reddish-purple | green | green | green |
CULTIVARS: N/A
HYBRIDS: N/A
