Daemonorops applanata Henderson & Nguyen Quoc Dung, 2018

Henderson, Andrew & Dung, Nguyen Quoc, 2018, A new species of Daemonorops (Arecaceae) from Vietnam, Phytotaxa 364 (2), pp. 202-204 : 202-203

Daemonorops applanata Henderson & Nguyen Quoc Dung sp. nov.

Type:— VIETNAM. Ha Tinh: Vu Quang District, Vu Quang National Park, road from Park Headquarters to Border Army Post, 18˚19’ N 105˚22’ E, ca. 100 m, 18 July 2007, A. Henderson & Ninh Khac Ban 3435 (holotype HN!, isotype NY!). Fig. 1 .

It differs from all other species of Daemonorops in Vietnam in its dense, flattened leaf sheath spines, at least some of which are laciniate.

Stems clustered, climbing, 8.5(4.0–20.0) m long, 2.7(2.2–3.6) cm diameter. Leaf sheaths tubular, closed opposite the petiole, with a knee below the petiole; leaf sheath spines dense, flattened, at least some laciniate; ocreas prominent, nonspiny, coriaceous, well-developed above petiole, open opposite petiole, persistent; flagella absent; petioles 25.8(16.0–60.0) cm long; rachises 146.9(105.0–230.0) cm long, the apices extended into an elongate cirrus without well-developed pinnae, usually with reduced or vestigial pinnae, adaxially flat, abaxially with more or less regularly arranged (at least proximally), distantly spaced clusters of dark-tipped, recurved spines, terminating in a shallow groove adaxially; pinnae 38(23–47) per side of rachis, regularly or irregularly arranged, linear, with spinules on veins adaxially and abaxially, the lateral veins approximately parallel, one terminating subapically, leaving a distinct or obscure, adaxial ‘broken’ vein; middle pinnae 37.2(25.5–54.5) cm long, 2.0(1.1–3.5) cm wide. Inflorescences diverging from sheath well below sheath apex, with two vertical ridges on the sheath distal to point of divergence; inflorescences erect to arching, short, without any recurved spines, terminating in a filiform apex sometimes covered with overlapping bracts; partial inflorescences not stalked, with a pulvinus in axil of rachis and partial inflorescence; rachis bracts splitting along their entire length, falling as the rachis elongates, leaving a conspicuous, circular scar on the rachis, papery in texture; rachillae sessile; staminate inflorescences branched to 3 orders, 51.3(44.0–60.0) cm long; staminate rachillae 1.5(1.0–2.1) cm long; staminate flowers alternately arranged; staminate sepals usually shorter than the petals, cupular, 3-lobed at the apex; stamens 6; filaments uniseriate, inflexed at the apex; pistillate inflorescences branched to 2 orders, length not recorded; pistillate rachillae 5.6(3.5–7.7) cm long, with dyads of 1 pistillate and 1 neuter flower borne on short, stout pedicels, the dyads alternately arranged; pistillate calyces cupular, broadly 3-lobed, much shorter than the corolla; fruits globose, 14.7 mm long, 12.0 mm diameter, yellow-brown; fruiting perianths explanate; fruit scales deeply channeled vertically; seeds 1 per fruit, basally attached, large, globose, not reniform in longitudinal section, the dorsal seed surfaces pitted, covered with a tanniniferous, non-fibrous sarcotesta; raphe branches not bifurcating from the attachment of the seed; endosperm with numerous, deep, pit-like ruminations; embryos at or near base of seed.

Distribution and habitat:—Central and southern Vietnam in lowland rainforest but more often in disturbed places near roads, at 280(20–790) m elevation.

Taxonomic notes:— The seven species of Daemonorops section Piptospatha in Vietnam — D. applanata , D. brevicaulis Henderson & Nguyen Quoc Dung (2010: 28) , D. fissilis (Henderson et al.) Henderson (2010: 27) , D. mollispina Dransfield (2001: 662) , D. nuichuaensis (Henderson et al.) Henderson (2010: 27) , D. ocreata Henderson & Nguyen Quoc Dung (2010: 29) , and D. poilanei — appear to form a group of related species, differing from other species in the section by the presence of a well-developed ocrea. All species are endemic to Vietnam and geographically isolated with the nearest other members of the section in southern Thailand.

Daemonorops applanata differs from all other species of section Piptospatha in Vietnam in its flattened, laciniate leaf sheath spines. It differs from D. poilanei in its spinulose pinnae (versus non-spinulose pinnae) and 14.7 mm long and 12.0 mm diameter fruits (versus 27.2–31.5 mm long and 17.6–25.7 mm diameter fruits). It differs from D. brevicaulis and D. nuichuaensis in its climbing stems (versus non-climbing); from D. mollispin a and D. ocreata in its closed leaf sheaths with a knee below the petiole (versus open sheaths without a knee); from D. fissilis in its well-developed petiole and rachis with 23–47 pinnae per side (versus short petiole and rachis with 8–12 pinnae).

There is some variation in the pedicel of the pistillate dyad. In most specimens the pedicel is scarcely developed, but in two specimens from Ba To in Quang Ngai province (Henderson et al. 3604, 3806) the pedicel is relatively well-developed. Ba To is home to several narrow endemics, for example Lanonia batoensis Henderson & Nguyen Quoc Dung (2017: 159) .

Additional specimens examined. VIETNAM. Quang Binh: Phong Nha-Ke Bang National Park , road near park entrance, 17°34’N, 106°18’E, ca. 20 m, 5 April 2007, Henderson et al. 3220 ( HN, NY) ; Phong Nha-Ke Bang National Park, road # 20, to Lao , 17°30’N, 106°15’E, ca. 100 m, 7 April 2007, Henderson et al. 3241 ( AAU, HN, NY) ; Phong Nha-Ke Bang National Park, Son Trach commune, 17°31’N, 106°16’E, 23 March 2007, Nguyen, V. D. et al. HNK1887 ( HN, NY). Thua Thien-Hue: Bach Ma National Park , road near park entrance, 16°14’N, 107°52’E, ca. 100 m, 12 April 2007, Henderson et al. 3256 ( AAU, HN, K, NY) ; Phu Loc district, Loc Tri, Bach Ma National Park , 16°14’N, 107°52’E, 16 May 2016, B. H. Quang et al. HN-NY1227 ( HN, NY) ; Phong Dien District, Phong Dien Nature Reserve , 16.577 N, 107.232 E, ca. 300 m, 5 March 2009, Henderson et al. 3527 ( AAU, HN, NY) ; same locality and date, Henderson et al. 3528 ( HN, NY) ; same locality, 8 February 2012, Bui Van Thanh et al. PD05 ( HN, NY) ; same locality, 9 February 2012, Bui Van Thanh PD07 ( HN, NY) ; A Luoi District, Sao La Nature Reserve , 16.072 N, 107.498 E, 579 m, 7 March 2009, Henderson et al. 3542 ( HN, NY) ; Quang Tri: Huong Hoa District, Bac Huong Hua Nature Reserve, 17 March 2012, Bui Van Thanh et al. BHH05 ( HN, NY). Da Nang City, Hoa Vang District , Ba Na-Nui Chua Nature Reserve , 16°00’N, 108°02’E, ca. 300 m, 18 April 2007, Henderson et al. 3294 ( AAU, HN, K, NY) ; Son Tra Nature Reserve, 16°06’N, 108°18’E, 93 m, 18 October 2015, Henderson & Nguyen Quoc Dung 4037 ( NY, VFM). Ha Tinh: Vu Quang District, Vu Quang National Park , road from Park Headquarters to Border Army Post, 18°20’N, 105°26’E, ca. 100 m, 17 July 2007, Henderson & Ninh Khac Ban 3429 ( AAU, HN, NY) ; Vu Quang District, Vu Quang National Park, road from Park Headquarters to Border Army Post , disturbed forest near road, 18°19’N, 105°22’E, ca. 100 m, 18 July 2007, Henderson & Ninh Khac Ban 3435 ( AAU, HN, NY) ; Can Xuyen District, Ke Go Nature Reserve, 18.134 N, 105.933 E, ca. 100 m, 26 February 2009, Henderson et al. 3488 ( HN, NY). Quang Tri: Da Krong District , Da Krong Nature Reserve , near Ba Long Commune , 16.651 N, 107.037 E, ca. 500 m, 28 February 2009, Henderson et al. 3495 ( HN, NY) ; same locality, 12 March 2012, Bui Van Thanh DK03 ( HN, NY). Quang Ngai: Ba To District, near Cao Muon , 14.80N, 108.68E, 80 m, 14 October 2009, Henderson et al. 3604 ( AAU, HN, NY) ; Ba To District, road from Ba To to Ba Cung , 14°44’N, 108°48’E, ca. 600 m, 18 July 2012, Henderson et al. 3806 ( NY, VFM). Khanh Hoa: Hon Ba Nature Reserve , road to summit, 2.11N, 108.98E, ca. 500 m, 6 July 2014, Henderson & Nguyen Quoc Dung 3907 ( NY, VFM) ; Khanh Vinh District, Khanh Trung Commune, Suoi Ca village, 21 May 2007, Nguyen Quoc Dung 2010 ( HN, NY). Quang Nam: Cu Lao Cham Island , ca. 150 m, 15˚57’ N, 108˚29’ E. 19 April 2017, Henderson & Nguyen Quoc Dung 4210 ( NY, VFM) ; Song Thanh Nature Reserve , 413 m, 30 March 2011, Bui Van Thanh ST08 ( HN, NY) .

Figures

FIGURE 1. A. Daemonorops applanata, plant with staminate inflorescences. B. Leaf sheath with dense, flattened spines, at least some laciniate (from Henderson et al. 3241).