AMORPHOPHALLUS SIZEMOREAE

PROTOLOGUE: Amorphophallus sizemoreae Hett., published in Blumea 46: 271 (2001).

Amorphophallus sizemoreae Hett., spec. nov. Amorphophallo pygmaeo similis, inflorescentia duplo majore in partibus omnibus, parte mascula parte feminea manifeste latiore, appendice duplo latiore differt. - Typus: Hetterscheid H.AM.985-T (holo L, spirit coll.), Thailand, Nakhon Sawan prov., Bo Ya Cave (coll. from a cultivated plant in the Leiden Botanical Garden; orig. coll. M. Sizemore).

DISTRIBUTION: N. Thailand: Thailand.

DISTRIBUTION NOTE: Thailand: Nakhon Sawan Province, Bo Ya Cave - the only locality known.².

SPECIES DESCRIPTION:

Tuber irregularly elongate and branching, the branches spreading or vertical, 3.5 cm across and 4-8 cm long, glossy dark brown. Petiole to 60 cm long and about 1 cm across, smooth, uniformly pale to olive green or pale to darker rich reddish brown. Lamina to 60 cm across with relatively few leaflets, the rachises winged nearly to the base; leaflets elongate elliptic, acuminate, to 20 cm long and 7 cm across, the upper surface deep rich green with a narrow bright lilac-red margin.²

INFLORESCENCE:

Inflorescence solitary and long-peduncled; peduncle 22-30 cm long and 0.7-0.8 cm across, smooth, pale reddish brown at the base grading to pale green above. Spathe erect, the base and limb separated by a shallow constriction, 7.5-9 cm long and 7-10 cm across, the limb concave with an acute top and involute margins; outside the base pale green, inside the base whitish green, the limb creamish within and without; the base within densely verrucate, the warts irregularly conical and often secondarily warted at the top. Spadix sessile, longer than the spathe, 17.5-21 cm long; female zone cylindric, 13-14 mm long and 9-10 mm across, the flowers slightly distant; male zone fusiform-cylindric with the base and top constricted, 4 cm long and 1.3 cm across, the flowers congested; appendix elongate conical, 12-15 cm long and 17-18 mm across, thin-walled and hollow, the base constricted and the top sharply acute, the surface shallowly rugulose, creamish, producing a strong gaseous smell during female anthesis. Ovaries depressed, orbicular, 2.5 mm across and 1.5 mm high, pale green, unilocular; style thick, 0.8 mm long and 1.3 mm across, dilating towards the top, creamish; stigma disciform, 2 mm across and 0.4 mm high, entire but with a central depression, the surface whitish and densely verruculate. Male flowers of 3-5 stamens; stamens 1 mm long, the filaments about 0.2 mm and fused; anthers about 0.8 mm long and 2-2.5 mm across, rectangular, truncate, creamish, the pores apical and elongate, the connective indistinct and very pale green. Pollen striate, ellipsoidal, 60 µm long.²

ECOLOGY:

Found at an altitude of about 60 m.²

PROPAGATION:

Our best results with this species were from early August cuttings when we achieved 96.9% rooting. The percentages declined after this time, and we were not able to root this species in two attempts in early November. With proper timing, this was among the species that rooted at the highest percentages in the trials.

ETYMOLOGY:

Named for Mary Sizemore, whose repeated collecting journeys through tropical Asia supplied much of the material and field information on which the modern revision of the genus rests. She collected the type.²

NOTES:

1. Amorphophallus sizemoreae belongs to a small group with Amorphophallus saururus and Amorphophallus pygmaeus. All three share a short, elongate, branching tuber, deep rich leaflets with a lilac margin, a slightly constricted concave spathe and slightly pyramidal lower male flowers.²

2. It is separated from both by a much broader appendix, a broader male zone and less strongly lobed stigmas; from Amorphophallus saururus additionally by much less strongly divided stigmas.²

3. The appendix is thin-walled and hollow.²

4. The species is known only from its type locality.²

REFERENCES:

1. Plants of the World Online, Royal Botanic Gardens, Kew — Amorphophallus sizemoreae Hett.

2. Blumea 46: 271 (2001) — protologue.

3. Alan Galloway — Amorphophallus sizemoreae, alangallowaybotanicals.com.

4. Propagation of Amorphophallus by Leaf Petiole Cuttings — Juniper Level Botanic Garden