Tên Khoa học: Alocasia evrardii Gagnep. ex V.D. Nguyen
Tên tiếng Anh:
Tên tiếng Việt: Ráy evrard
Tên khác:

Holotype: Vietnam, Lam Dong province, Da Lat, 19 Aug 1924, F. Evrard 1154 (P 00751091!). – Alocasia evrardii Gagnep. in Lecomte & al., Fl. IndoChine 6: 1150–1151, fig. 109, 7–11. 1942, nom. inval. (McNeill & al. 2012: Art. 39.1).

Diagnosis

Alocasia evrardii differs from all other species of Alocasia except A. vietnamensis in having a stipitate spadix with staminodes at the base of the female portion; it is close to A. putii Gagnep. (from Thailand) in its tuberous stem, but differs from that species in having ovate to suborbicular leaf blades (vs. elliptic in A. putii); it differs from A. vietnamensis in having a tuberous stem, peduncles c. ½ as long as the petioles, and a spathe limb dark green when young, light yellow at the base and violet-pink distally at anthesis, becoming reddish violet before falling off.

Description

Herbs seasonally dormant (?), 40–60 cm tall; stem tuberous, subglobose, 2–2.5 cm in diam., outside covered by fibres originating from dried petiole sheaths. Leaves 2 or 3 together, moderately peltate; petiole slender, 40–42 cm long, c. 1.5 cm in diam., sheathing for 10–14 cm from base, sheath light to medium green, sometimes light reddish to brownish, c. 1.5 cm wide at widest point; blade lighter green abaxially, medium green adaxially, ovate to suborbicular, 12–17(–25) × 10–15(–20) cm, base cordate and shallowly concave, apex obtuse or rounded, abruptly and conspicuously cuspidate, cusp 1–1.5 mm long; basal lobes adnate for c. 3 cm, semiorbicular or semielliptic, 5–6 × 5–6 cm; veins: primary lateral veins c. 5 pairs, basal veins c. 2 pairs, minor veins originating from both lateral veins and midrib and proceeding directly or indirectly forward to margin. Inflorescences 2–4 together, maturing sequentially; peduncle encased by a cataphyll for c. ⅓ its length, pale to medium green, more slender than petiole, c. 20 cm long; spathe 9.5–12 cm long; tube ovate to elliptic, 2–3 cm long, 1.5 cm in diam., persisting in fruit; limb dark green when young, light yellow at base and violet-pink distally at anthesis, becoming reddish violet before falling off, cymbiform at anthesis, 8–10 cm long, c. 4 cm wide when flattened; spadix stipitate, shorter than spathe, c. 6.5 cm long; stipe rather stout, c. 4 mm long; female portion slightly conical, c. 6 mm long, 2–2.5 mm in diam., base overed by staminodes; sterile portion slender, c. 15 mm long, 1.5–2 mm in diam., covered by staminodes; male portion light brown, oblong, c. 15 mm long, c. 4 mm in diam. at middle; appendix stipitate or sessile, dull white or light brown when young, light yellow or deep yellow during and after anthesis, stoutly subulate or subcylindric, c. 18 mm long, surface with many shallow concavities when young, deeply and elongate sulcate during and after anthesis, base truncate or oblong, equal to male portion in diam., apex acute; appendix stipe brown, 1–4 mm long, covered by thin soft projections. Female flowers: ovaries unilocular, subglobose, c. 1 mm in diam.; ovules 2–4, basal; style conspicuous, c. 0.3 mm long; stigma lobed, concave medially, margin shallowly divided into 4 lobes. Male flowers with 6 or 7 stamens united into a synandrium, 1.5–2 mm wide. Staminodes at base of female portion prominent, creamy brown to dark brown, 1.5–2 × c. 0.6 × c. 1 mm, surface concave at middle; staminodes of sterile portion long, flattened, parallelogram-shaped, 1–1.5 mm long, c. 0.3 mm wide, those at base of sterile portion longer, slightly concave at middle.

Distribution

Lam Dong and Binh Thuan provinces, S Vietnam, and Quang Tri province, C Vietnam; also Peunongs, Cambodia. Recent records only from Binh Thuan.

Ecology

Growing in humus deposits on sandstone under semievergreen forest at about 400 m above sea level.

Conservation

Alocasia evrardii was collected from three locations in Cambodia and Vietnam prior to 1942, when Gagnepain originally described the species. Since that date, it appears that no further gatherings were made from the forest around Da Lat (Lam Dong province, Vietnam). Meanwhile, the forests at Cua Tung (Quang Tri province, Vietnam) and Chedom (Peunongs, Cambodia) have been reduced in size or destroyed. However, in 2009, a small population with several tens of plants was found in the Takou Nature Reserve (Binh Thuan province, Vietnam). Further research is needed to gain a more complete and detailed knowledge of the distribution, size and stability of populations of the species. According to IUCN (2012) criteria, A. evrardii is provisionally categorized as Data Deficient (DD).

Etymology

The specific epithet evrardii was coined by Gagnepain in honour of the French collector, François Evrard (1885–1957), who collected in Vietnam during the years 1923–1929.

Additional specimens seen (paratypes)

Vietnam: Lam Dong province: Dalat, 10 Jun 1921, B. Hayata 758 (P 00751089); Binh Thuan province: Takou Nature Reserve area, 2 Oct 2009, H. T. Luu 428, H. T. Luu 429, H. T. Luu 431 & H. T. Luu 432 (VNM), H. T. Luu 430 & H. T. Luu 433 (HN). — Cambodia: Peunongs, C. Thorel (P 00751090); Chedom, C. Thorel (P 00751087).