Aristolochia faviogonzalezii T. V. Do, S. Wanke & C. Neinhuis, 2015

Do, Truong Van, Luu, Truong Hong, Wanke, Stefan & Neinhuis, Christoph, 2015, Three New Species and Three New Records of Aristolochia Subgenus Siphisia from Vietnam Including a Key to the Asian Species, Systematic Botany (Basel, Switzerland) 40 (3), pp. 671-691 : 672-677

Aristolochia faviogonzalezii T. V. Do, S. Wanke & C. Neinhuis sp. nov. —TYPE: VIETNAM. Ha Nam: Kim Bang district, Thanh Son community, on But Son limestone range, near the But Son cement factory, 20°31′387″N, 105°51′306″E, elevation 125 m, 11 Jan 2013, Do 14 (holotype: VNMN!; isotype: DR!).

Aristolochia faviogonzalezii is morphologically similar to A. cathcartii Hook. f. and A. saccata but differs from them by the following characters: leaf blade broadly ovate to cordate; inflorescence in clusters of 6–8(–10) cymes, inflorescence axis 5–9 cm long; perianth 3.5–5 cm high, outside with parallel dark purple veins or dots; upper tube uniformly dark purple without visible veins and dots; inner surface of limb lobes densely covered with purple warts; limb nearly rectangular, 2.4–2.6 cm high, 1.8–2 cm wide; upper half of the throat white with dark purple dots, lower half pinkish without visible dots.

Perennial, woody liana, 8–10 m high with many fasciculate, cylindrical roots. Stem slightly oval in cross section, young branches densely pubescent, becoming glabrescent, bark corky and furrowed when mature, internodes 15–18 cm long. Petiole 5–8(–10) cm long, twisted, densely pubescent. Leaf blade broadly ovate to cordate, (15–)18–23(–25) cm long, (13–) 15–20 cm wide, subcoriaceous, base cordate, sinus 2–3 cm deep, margin entire, apex acuminate or caudate, 1.0– 1.2 cm long, both surfaces and margin densely villous when young, then the adaxial surface dark-green and glabrous, basal veins five, palmate, secondary veins four to five pairs, pinnate; tertiary veins coarsely reticulate, slightly sunken adaxially, prominent abaxially. Inflorescence cymose on old woody stems, cymes in clusters of 6–8(–10), each cyme with three or four flowers, clearly separated from each other. Inflorescence axis 5–9 cm long (see Figs. 2E , 3G for details), pubescent. Bracteole clasping the axis, triangular, 2.5–3 mm long, 2–2.5 mm wide, sessile, both surfaces densely brown pubescent. Pedicel 1.2–1.4(–1.6) cm long, pendulous, densely brown villous. Ovary oblong, 1.1–1.3 cm long, 0.4–0.5 cm in diam, densely brown villous. Perianth horseshoe-shaped (in lateral view), 3.5–5 cm high, yellowish-white, outside densely brown hirsute with parallel dark purple veins or dots, inside glabrous. Utricle distinct from the tube, bell-shaped, 1.1–1.2 cm high, 0.6–0.7 cm in diam at base, 1–1.1(–1.3) cm in diam at apex, inside with a dark purple band and densely distributed trichomes. Tube horseshoe-shaped, 5.2–5.5 cm, folded upwards at its middle, lower tube strongly inflated, 1.6–1.8 cm in diam, and upper tube obliquely shortened funnel-shaped, without visible veins and dots, parallel to the utricle, gradually constricted at its base, uniformly dark purple, 1.4–1.5 cm high, narrower at base, 0.6–0.7 cm in diam and broader at apex, 1.5–1.6(–1.8) cm in diam. Limb with three unequal lobes, valvate pre-anthesis: two lateral lobes broadly triangular, each 2–2.2 cm wide, 1–1.1 cm high, middle lobe semicircular, 1.8–2(–2.1) cm wide, 0.4–0.5 cm high, margins of all lobes revolute during anthesis: lateral lobes fused, and middle lobe rib-like, forming a trumpet-shaped limb, nearly rectangular, 2.4–2.5 cm high, 1.8–2 cm wide, warty on inner surface of lobes dark purple. Upper half of throat white with dark purple dots, lower half pinkish, without visible dots. Annulus absent. Gynostemium with acute apices, 5– 6 mm high, 3–4 mm in diam, smooth; anthers 2.8–3 mm long, 1–1.5 mm wide, yellow. Capsule cylindrical, 5–6 cm long, 1.5–1.8 cm in diam, distinctly 6-angled, dark-brown, the angles villous, becoming glabrescent, basipetally dehiscent. Seeds ovoid, 6–7(–8) mm long, (3–) 4–5 mm in diam, not winged, the abaxial surface convex, and the adaxial surface deeply concave, both surfaces smooth. Figures 2 , 3 .

Vernacular Name — Common names in Vietnamese for this species are “Mô. c hýõng Favio” and “Phòng kỷ Favio”.

Distribution and Ecology — Known from the type locality, But Son limestone range in Ha Nam province, Kim Bang district, Thanh Son community and a neighboring locality in Ninh Binh province, Hoa Lu district, Ninh Hai community, Van Lam village, Bui valley ( Fig. 4 ). This species occurs on limestone covered with humus, in open broad-leaf forest and thickets with the following dominant species: Annonaceae ( Desmos chinensis Lour. , Fissistigma ), Begoniaceae ( Begonia ), Cucurbitaceae ( Gynostemma pentaphyllum (Thunb.) Makino ), Asparagaceae ( Dracaena cambodiana Pierre ex Gagnepain ), Euphorbiaceae ( Mallotus ), Malvaceae ( Byttneria , Sterculia lanceolata Cavanilles ), Moraceae ( Broussonetia ), Pandaceae ( Microdesmis ), Rubiaceae (Ophiorrizha, Psychotria ), Rosaceae ( Rubus ), Urticaceae ( Dendrocnide , Elatostema , Laportea ), at 120– 250 m.

Phenology — Aristolochia faviogonzalezii has been observed to flower from August to January while fruits are set from the beginning of December.

Ethnobotany — The whole plant is used for treatment of arthritis and rheumatism.

Etymology — The specific epithet honors Dr. Favio González who contributed extensively to the knowledge of Aristolochiaceae ranging from systematics and morphology to evolutionary biology during the last decades.

Conservation Status — The new species is known from a few populations within the limestone range lying on both Ha Nam and Ninh Binh provinces, northern Vietnam. However, the area has been severely damaged due to exploitation by cement factories. In addition, both populations are outside of protected areas and local people continue to impose strong pressure on the remaining forest patches for medicinal plants, firewood, and converting the vegetation into corn fields. Thus, according to the criteria established by the IUCN (2013), the new species should be considered as endangered (EN) due to the restricted occurrence, small population size, and the possible decline in the quality of habitat.

Morphological affinities — Aristolochia faviogonzalezii is morphologically similar to A. cathcartii and A. saccata , occurring in the eastern Himalayas and southern China. However, A. faviogonzalezii can be clearly distinguished from A. cathcartii by the leaf blade broadly-ovate to cordate with acuminate or caudate apex (vs. narrowly ovate to lanceolate-ovate with acute to shortly acuminate apex), inflorescence axis 5–9 cm long (vs. 2–4 cm long), perianth 3.5–5 cm high, with parallel dark purple veins or dots (vs. 3.0– 3.5 cm, with purple reticulate veins), upper tube uniformly dark purple without visible veins and dots (vs. yellowish-white with purple veins and dots), inner surface of limb lobes densely covered with dark purple warts (vs. dark purple warts and bristle-like papillae), upper half of throat white with dark purple dots, and lower half pinklish without visible dots (vs. uniformly yellow, densely covered with purple dots). Aristolochia faviogonzalezii also differs from A. saccata by the shape of the leaf blade (broadly-ovate to cordate vs. ovate-oblong to lanceolate), perianth (6.5–7 cm, yellowish-white with parallel dark purple veins and dots vs. 4–4.5 cm, white with purple reticulate veins), throat (upper half white with dark purple dots, and lower half pinkish vs. uniformly yellow) ( Table 1).

Additional Specimens Examined — VIETNAM: Ninh Binh. Hoa Lu district, Ninh Hai community, Van Lam village, Bui valley, 27 Feb 2000, Chien & Hung 4488 (NIMM).

Figures

FIG. 2. Aristolochia faviogonzalezii. A. Habit. B. Front view of open flower. C. Lateral view of open flower. D. Close up of gynostemium. E. Capsule (Arrowhead indicates the inflorescence axes). F. Multicellular hairs. Drawings by Nguyen Huu Quyet from the type specimen.

FIG. 3. Aristolochia faviogonzalezii (A-G). A. Habit. B. Adaxial leaf surface. C. Abaxial leaf surface. D. Cymes on old woody stems. E. Front view of open flower. F. Lateral view of open flower. G. Capsule (Yellow arrowhead indicates the inflorescence axes) – Aristolochia cathcartii. H. Front view of open flower of A. cathcartii. A-C & G. Photographs by Do Van Truong. D-F. Photographs by Nghiem Duc Trong from the type population. H. Photographs by Andrew Gavin at Eden Botanic Garden.

FIG. 4. Map showing the distribution of new species and new records of Aristolochia subgenus Siphisia from Vietnam.