Trichosanthes conferta Duyfjes, Nuraliev & Luu, 2016

Duyfjes, B. E. E., Nuraliev, M. S., Luu, H. T., Huynh, N. T., Ngo, V. C., Kuznetsov, A. N. & Kuznetsova, S. P., 2016, Two new species and one new species record of Trichosanthes (Cucurbitaceae) from Vietnam, Blumea 61 (3), pp. 267-271 : 267-268

1. Trichosanthes conferta Duyfjes, Nuraliev & Luu , sp. nov. ― Fig. 1a‒f

Markedly differing in male petals with entire margin (fringed or deeply lacer- ated in all known Trichosanthes species). ― Type: Luu Hong Truong, Huynh Nhan Tri & Ngo Van Cam 1150 (holo MW; iso L L.3955619, SGN), Vietnam, Kon Tum Province, Kon Plong District, Ngok Tem Commune , N14°43'43.3" E108°20'04.3", 1120 m elevation, 18 Apr. 2016, male fl .

1 Naturalis Biodiversity Center, section Botany, P.O. Box 9517, 2300 RA Leiden, The Netherlands;

corresponding author e-mail: [e-mail].

2 Joint Russian-Vietnamese Tropical Scientific and Technological Center, Cau Giay, Hanoi, Vietnam; e-mail: [e-mail].

3 Faculty of Biology , M. V. Lomonosov Moscow State University, 1, 12, Len- inskie Gory, 119234 Moscow, Russia .

4 A.N. Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences, Leninsky 33, Moscow, Russia.

5 Southern Institute of Ecology, Vietnam Academy of Science and Technology, 1 Mac Dinh Chi, District 1, Ho Chi Minh City, Vietnam.

6 Faculty of Agriculture & Forestry,Tay Nguyen Technical School for Agriculture and Forestry,438 Truong Chinh,Pleiku City, Gia Lai Province, Vietnam.

7 Tropical Research Centre,Forest Science Institute of Central Highlands and South of Central Vietnam, Chi Lang Ward, Pleiku City, Gia Lai Province, Vietnam.

Etymology. The specific epithet refers to the crowded flowers in the male inflorescence (Latin: conferta = crowded).

Trailing or climbing subherbaceous perennial (?) vine; stem between adult leaves c. 3 mm diam, grooved on drying, not reddish tinged; whole plant appearing as glabrous, but sparsely minutely (appressed) greyish-hairy, hairs less than 0.1 mm long, hairs more obvious in inflorescence; dioecious. Probract linear, 10‒12 mm long. Tendrils 2- (or 3-)branched, 10‒15 cm long, point of branching 1‒3 cm from the base, one branch much longer. Leaves dispersed when trailing, showing up as distichous when creeping ( Fig. 1a ); petiole c. 2 cm long, c. 2 mm diam; lamina brown on drying, thinly coriaceous, entire, ovate-elliptic, (8‒)10‒15 by 4.5‒9 cm, glands absent, cystoliths absent, base broadly rounded or shallowly cordate, near the insertion with the petiole with two inconspicuous lobes (not glandular), margin entire, smooth or with remote dents c. 0.5 mm long, apex acute-acuminate; veins ± 3- or 5-pli-nerved at base and 1 or 2 (or 3) pairs from the midrib, tertiary venation coarsely reticulate, raised below. Male raceme minutely grey or pale brown hairy, hairs c. 0.1 mm long; peduncle straight, c. 10 cm long, 1.5‒2 mm thick, at base co-axillary with or without a single flower-pedicel 6–8 cm long; rachis short, not thickened, 0.5–1.5 cm long, 8–10-flowered, the flowers condensed, sub-umbellate; bracts persistent (?), narrowly elliptic (leaving sight on younger buds), 10‒20 by c. 2.5 mm, long-narrowed at base, margin entire, apex long-acute, glands minute (but see note 3). Male flowers finely grey-brown hairy; pedicel erecto-patent, persistent, 10–15 mm long, not distinctly articulated to the flower; receptacle tube very minutely hairy inside, long-cupshaped, c. 15 mm long, at throat c. 8 mm wide; sepals erect, (long-) triangular, entire, 2.5‒3 mm long, petals in bud outside finely brown hairy, ± valvate, the bud narrowed (not rounded) towards the apex; petals white, spreading, obovate-oblong, c. 20 mm long, broadest towards apex where irregularly lobed or undulate, without hair-like threads; stamens 3 (two 2-thecous, one 1-thecous, or occasionally 5, all 1-thecous), inserted about halfway to the receptacle-tube, reaching to the throat of the receptacle tube, filaments free, glabrous (glandular hairy), widening to the anthers, anthers 3, tightly connivent into a broadly ellipsoid synandrium, at apex sterile, flat with some fleshy bulges, anthers two 2-thecous, one 1-thecous, thecae sigmoid, minutely hairy at their margins. Female flower, fruit, and seed not known.

Distribution ― S Vietnam, known only from the type locality.

Habitat & Ecology ― Climber on trees along road near river; 1120 m elevation; flowering in April.

Notes ― 1. The here presented description of T. conferta is based on the herbarium collection Luu Hong Truong et al. 1150 and on photographs made by Luu Hong Truong in the field in 2016, as well as on those previously made by Nuraliev in 2015, on the same locality.

Trichosanthes is night-flowering, the petals are white, apparently fading to purplish brown at the end of the night.

2. Trichosanthes conferta resembles most the rather widespread T. truncata C.B.Clarke. The latter species differs in lacking a probract, in longer petioles, shorter and broader male bracts, reflexed sepals, fringed petals, and a more elongate rachis in the male raceme. In T. conferta the probract is small and narrow and may be overlooked. The new species has conspicuously straight male peduncles bearing at apex the flowers close together, reminiscent of an umbel, one flower in anthesis each day. The lack of thread-like fringes on the petals is unique in the genus.

3. The male bracts are abaxially covered with numerous minute glands which in fresh leaves look like bright green convex warts, and when dry as pale discs, c. 0.1 mm diam. They are much smaller than the glands in other species, c. 1 mm diam or more.

Figures

Fig. 1 Trichosanthes conferta Duyfjes, Nuraliev & Luu. a. Portion of trailing plant; b. male inflorescence; c. idem; d. idem, note pedicel of single basal male flower; e. male bud longitudinally opened showing 3 stamens; f. male flower. ― Photos: a‒c, f: Maxim Nuraliev; d, e: Hong Truong Luu.