Drosera finlaysoniana Wall. ex Arn.

Krueger, Thilo & Fleischmann, Andreas, 2021, A new species of Drosera section Arachnopus (Droseraceae) from the western Kimberley, Australia, and amendments to the range and circumscription of Drosera finlaysoniana, Phytotaxa 501 (1), pp. 56-84 : 63-74

2. Drosera finlaysoniana Wall. ex Arn. in Hook. [as “ finlaysoni ”] ( Figs. 3–9 )

Lectotype (designated here): —[ VIETNAM. Municipality Đà N ẵng], Hb. Finl. [Herbarium Finlayson], Turun Bay [Turon Bay = Da Nang Bay] E. I. C. [East Indian Company], without date [collected 15–19 September 1822], Wallich Cat. no. 3752 [= G. Finlayson 507] ( E00206577 photo!; isolectotype K000217501 ! [from Wallich’s herbarium K-W]; isolectotype K000659132 ! [from Herbarium Hookerianum via the East Indian Company Herbarium ]; isolectotype G00414356 photo!). ( Fig. 4 )–for notes on lectotypification see section below.

≡ Drosera finlaysoniana Wallich (1831 : n. 3752), nomen nudum (Art. 38.2 Ex.1 of ICN).

= Drosera angustifolia Mueller (1855: 7) .

Lectotype (designated by Barrett & Lowrie 2013: 531):—[ AUSTRALIA. Victoria]: Ad ripam glareosam humidam tingiore imbuis inundatam lacus Yualb prope fl.[umen] Murray [at gravelly soaking moist inundated banks of a lake on the Victorian side of the Murray River near Euston, see Mueller (1855: 7; 1862: 58)], Dec [18]53, F. Mueller s.n. (MEL 96369 photo!; isolectotype LD; probable isolectotype MEL 96386 photo!).

= Drosera indica f. robusta Bailey (1913: 115) .

Type: —[ AUSTRALIA]. Queensland: Mill Stream Falls, Ravenshoe , Jun 1913, E. W . Bick s.n. (holotype BRI AQ0183206 , isotype K!) .

Description: —Annual herb, (5–)7–30(–90) cm tall. Roots simple, short, slightly succulent, terete, poorly branched. Stem upright or ascending, (3–)7–25(–75) cm long, simple (unbranched), terete, (0.9–)1.3–3.0 mm in diameter, green to bronze, turning reddish with age, internodes 1–3(–15) mm long in flowering specimens; stem covered with indumentum consisting of two different types of trichome: 0.05–0.15 mm long, translucent, biseriate, double-tipped trichomes (= type 5 sensu Länger et al. 1995) and 0.1–0.3 mm long, secretory capitate trichomes with uniseriate, translucent stalk (base often reddish) and flattened gland head secreting a translucent mucilage droplet ca. 0.1 mm in diameter. Leaves filiform, (30–)50–150(–220) mm long in flowering-sized specimens, straight, transversely elliptic to depressed transversely reniform in cross-section, lateral margins slightly reflexed, vernation circinate; freshly developed leaves held erect or patent and with slightly curved lamina, leaves held horizontal and lamina straight with age, senescent leaves persistent, patent or reflexed towards the stem; stipules absent; petiole absent (leaves sessile: tentacle-bearing part of the leaf reaching all the way to the stem/leaf axil); lamina comprising the entire leaf length, narrowly linear-lanceolate with long acuminate tip, (30–)50–150(–220) mm long (excluding tentacles), (1.6–)2.0–4.0(–4.5) mm wide (excluding tentacles) near the leaf base, gradually tapering towards the apex; lamina yellowish-green, often emitting a honey-like scent, its adaxial surface covered with stalked, carnivorous, secretive capitate glands (tentacles) 1–4 mm long, tentacle stalk translucent white or yellowish-white, with regular, hemispherical microscopic projections, tentacle gland head translucent white, orange-yellow or red, all tentacles with radially symmetric gland head; additionally, lamina adaxial surface and margins covered with 0.05–0.15 mm long, translucent, biseriate, double-tipped trichomes (= type 5 sensu Länger et al. 1995) and T-or Y-shaped trichomes (= type 14 sensu Länger et al. 1995; found in highest numbers at the leaf base) with translucent uniseriate stalk (0.05–0.40 mm long) and bifurcated, yellowish or pale pink head 0.2–0.3 mm wide; lamina abaxial surface and leaf margin indumentum identical to stem indumentum). Inflorescences (1–)2– 7(–10), each forming a (2–)6–20(–26)-flowered scorpioid cyme with persistent bracts; inflorescence indumentum (covering peduncle, rhachis, bracts, pedicels, calyx and sepals) identical to stem indumentum; young inflorescences yellowish-green or bronze-green, turning reddish with age; scape (30–)60–180(–260) mm tall including peduncle; peduncle (15–)20–80(–110) mm long, shorter than the leaves in length or at most equalling them, terete, 1.0–2.0 mm in diameter, usually ascending ± horizontally, even young inflorescences often diverging at an angle>45° from the stem, fruiting inflorescences often slightly curving downwards from their middle; fruiting pedicels spaced by (2–)3–15(–27) mm; pedicels terete, 0.5–1.0 mm in diameter, (2–)4–12(–20) mm long in fruit; pedicels straight or just gently arcuated upwards, held upright at anthesis and spreading horizontally from the rhachis in fruit (sometimes pedicels sharply bent upwards at the apex so that the fruiting seed capsules are held upright). Bracts persistent, 1.5–4.0(–4.5) × 0.2–0.8 mm, subulate, margins entire, apex acute to shallowly truncate, adaxial surface glabrous, abaxial surface indumentum identical to stem indumentum. Flowers (6–)7–14(–20) mm in diameter. Sepals 5, basally adnate, slightly imbricate in bud, especially at their apices, lanceolate-elliptical, margins serrate or entire, (2.0–)2.5–6.0 mm long, (0.8–) 1.2– 2.3 mm at their greatest width, abaxial surface with indumentum identical to stem indumentum. Petals 5, narrowly obovate to obovate, (3.0–)4.5–7.0(–9.0) mm long, 2.5–5.0 mm wide at widest point, apical margin slightly irregularly crenulate, petals not overlapping, pale pink or white (rarely bright pink). Stamens 5, narrowly lanceolate, 2.0– 2.5 mm long, 0.3–0.5 mm wide; filaments linear, ca. 1 mm long, ca. 0.3 mm wide, white; anthers bithecate, much shorter than the filament in length, 0.6–1.0 mm long, connective only slightly dilated, narrowly triangular, 0.2–0.4 mm wide, subequal to the thecae; thecae pale yellowish-white; pollen yellow or rarely pale yellowish-white. Ovary 3-carpellate, fused, subglobose, 1.0– 1.5 mm in diameter, glabrous, pale green. Styles 3, each basally divided into 2 entire style-arms; style-arms translucent white, 1.2–1.5(–2.0) mm long (excluding stigmatic portion), flagelliform, terete, 0.1–0.2 mm in diameter, glabrous, positioned horizontally, graduating into stigmatic part; stigmas ca. 1 mm long, translucent white, apex strongly curved upwards, stigmatic surface papillate. Seeds numerous, (350–)400–500 × (250–)290–350 µm in Australian specimens, 300–400 × 200–280 µm in Indochinese specimens, ovoid to broadly ellipsoidal, testa black with grey wax cover, testa surface very regularly foveate-reticulate, with anticlines pronounced and raised, periclinal walls tabular, occasionally with iridescent shine underneath wax cover, periclines and anticlines covered with microscopic, dendritic, bladed wax crystals.

Etymology: —The species epithet commemorates Scottish surgeon and naturalist George Finlayson (1790–1823), who explored and botanised Thailand and southern Vietnam as accompanying medical officer to John Crawfurd’s Mission in 1821–1822 ( Finlayson & Raffles 1826, Watson 2013). During this expedition, Finlayson made the first collection of the Drosera taxon that was named posthumously in his honour as Drosera finlaysoniana by Wallich (1831), however lacking a description or diagnosis like most of the names published in Wallich’s Catalogue, rendering the name a nomen nudum. The name was later nomenclaturally validated by Arnott in Hooker (1837) as “ D. finlaysoni ”, however Wallich’s original spelling of the epithet has to be retained, see ICN Arts. 60.1 and 45.6 ( Turland et al. 2018).

Distribution: — Drosera finlaysoniana occurs in Australia (Western Australia, Northern Territory, Queensland, New South Wales, South Australia, Victoria), southern China (Provinces Fujian, Guangdong, Guangxi, Hainan), northeastern Taiwan (Counties Hsinchu, Miaoli, Taichung, Taipei, as well as Kinmen Island) and Vietnam (Northeast, North Central Coast, South Central Coast and South East regions: Provinces Nghệ An, Khánh Hòa, Quảng Trị, Quảng Ninh, Thừa Thiên Huế, Bà Rịa-Vũng Tàu, Bình Thuận, and Municipalities Ðà Nẵng and Hanoi) ( Fig. 3B ). In Australia, the species is widespread in the northern and central parts, where it occurs from ca. 10 m to well above 1000 m elevation (it has been collected from “near summit of Mt Zeil” [J.H. Willis s.n.] in the Northern Territory, which is the highest mountain on the Australian mainland outside the Great Dividing Range with an elevation of 1531 m). The Indochinese records of D. finlaysoniana are all situated along the coast of the South China Sea ( Fig. 3B ), while the species does not seem to cross the Mekong River to the Gulf of Thailand. All Indochinese populations are found in coastal regions, some even at offshore beaches and lagoons; the most inland record is ca. 80 km from the coast ( Vietnam, surroundings of Hanoi, C. d’Alleizette s.n., P04583159), and all are at lowland elevations, from sea level to 100 m, reaching the species’ highest localities in Taiwan at 80–100 m elevation and on Hainan island, China, at 100 m a.s.l. Not a single occurrence could be confirmed from Cambodia, neither from herbarium records nor from field observations in suitable habitats along coastal seepage habitats (F. Mey, pers. comm.), where the related species D. indica and D. serpens are abundant. Despite earlier (erroneous) mentions of D. finlaysoniana from Laos ( Barrett & Lowrie 2013; who do not cite any vouchers from the country), India ( Lowrie 2014, Lowrie et al. 2017b), southern Japan ( Lowrie et al. 2017b) and the Philippines ( Lowrie et al. 2017b), no herbarium specimens or observation data of that species could be traced from any of these four countries. We therefore conclude that D. finlaysoniana is absent from India, Cambodia, Laos and Japan, although its presence in the Philippines cannot be excluded considering the rather poor botanical exploration of some remote Philippine islands, and in the light of recent Drosera range extensions following floristic surveys ( Fleischmann & Coritico 2016, Robinson in Lowrie et al. 2017b). A single questionable herbarium record exists from Thailand, from today’s Prachuap Khiri Khan Province (a duplicate of Collins 1621 at P), however the collection site does not match typical habitat for the species, and no further records of D. finlaysoniana exist from any nearby area in Thailand, nor the same site, which is a touristic and frequently visited spot today. Therefore, we cannot exclude the possibility that the locality has been mixed up in the herbarium record, yet the specimen is clearly D. finlaysoniana .

Records and depictions of “ Drosera indica ” from New South Wales (FlNSW 1990, Harden 2000, Gibson 1999, 2002), Victoria ( Conn 1996), central Australia ( Marchant 1981, Latz 1995), mainland China ( Ruan 1984, 1991, Lu & Kondo 2001, excluding Hong Kong) and Taiwan ( Liu 1976, 1996) exclusively refer to D. finlaysoniana , which is the only representative of D. section Arachnopus occurring there. Reports and illustrations of “ Drosera indica ” from Hainan ( Merrill 1927, Chen 1964, Lu & Kondo 2001) and Vietnam ( Gagnepain 1908 –1923, Lecompte 1965) may refer to either D. finlaysoniana , D. indica s.str. or D. serpens , as all three species occur in these regions, sometimes two of them syntopically (see Notes under Specimens Examined: Electronic Appendix). Reports of D. indica from Hong Kong ( Lu & Kondo 2001) and Thailand ( Larsen 1987) indeed refer to D. indica s.str., which is the sole member of D. section Arachnopus recorded there. At the northernmost limit of its range in north-western Taiwan, Drosera finlaysoniana reaches a latitude of ca. 25.07° North, at its southernmost outpost in Victoria, Australia, it reaches 34.72° South ( Fig 3B ). An observation record from Adelaide, South Australia ( Atlas of Living Australia 2020) could not be confirmed and is excluded from the species’ range here.

Drosera finlaysoniana is absent from Japan, the Indian subcontinent and the Malesian biogeographical region ( Indonesia, Malaysia, Brunei, Singapore, the Philippines, East Timor, and New Guinea), and most likely also from Thailand. This results in a disjunct Indochinese–Australian range ( Fig. 3B ; by no means a “more or less continuous distribution between Australia and Vietnam ”, as concluded by Barrett & Lowrie 2013), a rare biogeographic pattern, which is shared by the likewise carnivorous Utricularia odorata Pellegr. ( Lentibulariaceae Rich. ) (Taylor 1989; however, that species is much more localised in northern Australia and absent from southern China), as well as—with a few additional occurrences in Malesia and one in Sri Lanka —by the genus Stylidium Sw. ( Stylidiaceae R.Br. ) ( van Slooten 1954 ). In addition, D. finlaysoniana occurs in very different climatic areas on either side of the equator. While the Indochinese populations experience humid subtropical or tropical savanna climates (Köppen climate types Cwa, Cfa and Aw), almost all Australian populations are found in hot arid or semi-arid climates (BWh and BSh), with only few occurrences in tropical savannah climate (Aw, these occur in the central Kimberley, southern Top End and Cape York regions; Fig. 3B ). Interestingly, seeds of D. finlaysoniana from Indochinese provenances are ca. 25–30% smaller in size than those of Australian specimens ( Fig. 9 ; Barrett & Lowrie 2013). This could be related to a more pronounced dry seed dormancy of the more arid Australian habitats, while the Indochinese populations do not need to survive a prolonged dry seed dormancy (e.g., Chinese populations are reported to grow more or less continuously year-round; Ruan 1991). Drosera finlaysoniana is the only Australian species of D. section Arachnopus which is largely absent from the area of tropical savanna climate (Köppen climate type Aw) in northern Australia.

Ecology, habitat and phenology: —Annual. In Australia, Drosera finlaysoniana grows in a wide range of seasonally wet or inundated habitats. It has been recorded from sandy or rocky areas in or adjacent to freshwater lakes, swamps, creeks, riverbeds, sandstone or granite outcrops (inselbergs), dunes, claypans, soaks, springs and seepage areas. Flowering occurs from late March to October, which are typically the drier months of the Australian desert climates. In Indochina, D. finlaysoniana has been collected in flower and fruit year-round ( Ruan 1991; see also Specimens Examined: Electronic Appendix), and the species occurs in perennial or seasonal open wetlands, seepage areas, at the margins of rivers, ponds, dams and lagoons, on wet rock, wet oligotrophic sands, but it is also frequently reported from rice fields and—at least historically—even in urban areas (see Specimens Examined: Electronic Appendix).

Conservation status: —Least Concern (LC) regarding the species’ global range ( IUCN 2012, Bourke 2018). Drosera finlaysoniana is widespread and common throughout many parts of its range. Within Australia, it is currently not listed as threatened by any state except Victoria where it is only known from a single locality (Hattah-Kulkyne National Park) and thus is listed as Vulnerable (vicflora.rbg.vic.gov.au). The species may also be threatened in some regions of China and Vietnam, as most records were made in the 1930’s and earlier. Many of these historical localities are now urbanised or have become developed, thus some of the populations shown for Indochina in Fig. 3B might have been lost by now.

Notes on the lectotypification: —Wallich’s exsiccate series was distributed to several herbaria, however the Finlayson collections included in that series comprise only few duplicates ( Candolle & Radcliffe-Smith 1981, Watson 2013). Of Wallich Cat. No. 3752 we could only trace four duplicates (i.e., syntypes of Drosera finlaysoniana ), of which two are deposited at K in Wallich’s and Hooker’s Herbaria (K000217501! and K000659132!, respectively). Indeed, most of Wallich’s types and his main set are housed at K ( Stafleu & Cowan 1979). A further duplicate is housed at the Herbarium of the Royal Botanic Garden Edinburgh (E), to where Arnott’s herbarium was finally transferred ( Stafleu & Cowan 1976). Barrett and Lowrie (2013) mention the duplicate from G as the “ holotype ” of D. finlaysoniana , indicating that the original material consulted by Arnott has to have been a sterile specimen. Indeed, Arnott himself noted that he had only seen a single specimen of Wallich’s D. finlaysoniana , “and that an imperfect one” ( Arnott 1837: 314). However, as Arnott (1837) describes details of the inflorescence (“racemis elongatis multifloris”; the plural might indicate that he examined a specimen with more than one inflorescence present), including its indumentum and seed characters, it cannot be a sterile specimen that he consulted. Furthermore, the syntype at G does not bear any indication that it had been consulted by Arnott. The specimen examined by Arnott would have had to have been a fertile specimen, and an “imperfect” one lacking (open) flowers, but with infructescence(s) present. K000217501 comprises a) two individuals with b) some flowers present thus can be excluded as having been seen by Arnott. K000659132 contains a single, rather incomplete specimen with one infructescence (and some detached seed capsules which apparently had been dissected for examination), and E00206577 is a single large specimen with six infructescences. Hence one of these two specimens very likely represents the single specimen examined personally by Arnott, i.e. the holotype. The E duplicate is accompanied by a handwritten diagnosis of the plant (likely of Arnott’s hand, at least not in conflict with the typography of his handwritten correspondence) that almost literally agrees with Arnott’s published description in Hooker ( Arnott 1837). Therefore, it is reasonable to assume that the E duplicate of Wallich Cat. No. 3752 is the specimen which Arnott examined for the description of D. finlaysoniana and hence that gathering is selected as the lectotype here. As duplicates of Wallich Cat. No. 3752 are found in different herbaria (syntypes according to the Art. 9.6 of ICN; Turland et al. 2018), a lectotypification is required (ICN Art. 9.17; Turland et al. 2018), which thus far has not been done for the name Drosera finlaysoniana . The mention of a “ holotype ” by Barrett and Lowrie (2013) and Lowrie (2014) does not constitute an inadvertent lectotypification (see ICN Art. 7.11; Turland et al. 2018).

Notes on the collector: —The specimen from Wallich’s Herbarium (K000217501) is the only duplicate of No. 3752 containing a note (possibly from Wallich’s hand) on the original collector’s collection number (“ G. Finlayson 507, Turon Bay”) in addition to the lithographed original labels cut from Wallich’s Catalogue that are present on all specimens of the exsiccate series (except the lectotype in E, which has that information transcribed directly on the sheet, including the typo “Turun Bay”). Wallich’s Catalogue labels only state “Hb. Finl. e sinu Turon” [Herbarium Finlayson, from the Bay of Turon] as source, but additionally mention “(Coet. spec. 1242-44)”, i.e. an internal crossreference to the other (“coeterae”) three Drosera species mentioned in previous entries in Wallich’s catalogue (Wallich Cat. Nos. 1242, 1243 and 1244).

Notes on the collection date: —The collection date of the type material is not evident from the herbarium specimens of Wallich Cat. No. 3752, but can be concluded from Finlayson’s expedition journal ( Finlayson & Raffles 1826): the expedition landed at Turon Bay on 15 th September 1822. On p. 331, Finlayson mentions “[t]he daily excursions of our party [that] were the means of adding many valuable plants to my collection”, before they re-embarked from the bay of Turon for the village of Turon on September 20th ( Finlayson & Raffles 1826). Hence Finlayson’s plant collections at the bay of Da Nang (the former Turon) during which the type gatherings of D. finlaysoniana were made took place 15–19 September 1822.

Notes on the type locality of Drosera angustifolia :— The exact location of the locus classicus of Drosera angustifolia is not evident from the type label, but was given by Mueller (1855), and later under the entry of D. indica by Mueller (1862: 58), as “[…]around the fresh-water lakes near Eustone on the Murray River, rare”. Strangely, Barrett & Lowrie (2013) locate the locus classicus in New South Wales, although Mueller (1855, 1862) clearly denoted that he collected the plant in the state of Victoria. The most likely locality of Mueller’s collection is within Hattah-Kulkyne National Park, possibly near Lake Mournpall or Lake Lockie (ca. 38 km WSW of Euston) which is the only known locality of D. finlaysoniana within Victoria, based on more recent herbarium records (J.H. Browne 851, T. Mitchell s.n.). The area around Lake Mournpall was botanised by Mueller, denoted by him as “Moornpool” (e.g., on F. Mueller s.n., Acacia anthoclada, MEL 0026133A photo!). Mueller (1855: 7) already recognised his D. angustifolia as very close to D. finlaysoniana and highlighted it to be “one of the many tropical forms of plants, which, transgressing the torrid zone, advance so far southerly as the Murray desert”.

Specimens Examined:— Drosera finlaysoniana (oldest known and most recent records are listed for each state/ country of occurrence, for full specimens list see Electronic Appendix). AUSTRALIA. Western Australia: Between Barrow’s [=Barrow] & Rawlinson’s [=Rawlinson] Range , 1873, W. E. P . Giles s.n. ( MEL 0096394 A photo!); Nallan Lake, 30 m E of Great Northern Hwy. , 20 km NNE of Cue , Western Australia, lake margin, reddish-brown sand, 13 July 2020, T . Krueger 6 ( PERTH!, MIN!) . Northern Territory: Between the Finke River and Charlotte Waters , 1885, F. A. H . Kempe 26 ( MEL 0096436 A photo!); 1.2 km West of Attack Creek crossing of Stuart Highway, occasional in seepage area on plain near creek, sandy loan, herb-rich Hummock grassland, 11 Jun 2006, D. E . Albrecht 12001 ( K!, DNA—voucher for Millenium Seed Bank, as “ Drosera indica ”) . Queensland: Normantown [=Normanton], 1875, A . Henry s.n. ( MEL 0096359 A photo!); Adjacent culvert crossing of the Barron River , upstream and 3 km NW of Kurand, sand and silt deposits over and about exposed geology forming rapids at this point in the river, 09 August 2009, G. W . Wilson 588 ( CANB 723361.1 photo!, CNS) . Victoria: Hattah Lakes National Park , ca 2km NNW Hattah Camping Ground, close to water after flood recession, 14 December 1981, T . Mitchell s.n. ( MEL 0595758 A photo!); Hattah- Kulkyne National Park , E side of Mournpall Track, ca 1.4km S of Lake Mournpall , growing on the edge of a flood plain depression recently filled by river flood, in open area protected from winds by Callistemon brachyandrus , sandy clay soil, 04 March 1993, J. H . Browne 851 ( MEL 2014399 A photo!) . South Australia: Central Australia , 1883, C. G. A . Winnecke 27 ( MEL 0096435 A photo!); 6 km ESE of Bloodwood Bore, Cordillo Downs Station , sandplain, brown loam soil, 19 August 1991, F. J . Badman 4942 ( MEL 1617508 A photo!) .

CHINA. Guangdong: Swatow [Shantou], 180 miles N. E. of Hong Kong , 1901, J. M. Dalziel s.n. ( HUH photo!, IBSC-117088 photo!, P-04583188 photo!); Guangwei , Zhuhai County, Sanzao, wetland, 16 August 1992, Z. M. Wu 84975 ( MO photo!) . Guangxi: Hepu County, Zhongshan, 1952, J. Zhong 809459 ( IBK photo!); Hepu, Yin field water, 13 April 1956, Plant Investigation Team of Hepu District 2011 ( IBSC photo!, PE photo!) . Fujian: Prov. Fohien [Fujian], 1861, Hance 1425 ( P photo!); Bantou Reservoir, wet grass, 21 October 1980, G. Ye 1763 ( FJSI photo! PE photo!) . Hainan: Ching Mai District [Chengmai County], Tai Wong Ling and vicinity, Tung Pin Tin Village , moist, level land, sandy soil, meadow, cult. field, abundant, 19 February 1933, C. I. Lei 385 ( IBSC photo!, NAS photo!, P!, PE photo!); Dan County , on the way from Paipu to Shatao, 24 March 1982, G. Fu 2780 ( IBSC photo!) .

TAIWAN. Taoyuan County, Luchu, 10 September 1908, S. Sasaki s.n. (TAIF-11100 photo!); Yangming Lake , 0–50 m, 20 October 2018, S. W. Chung 13593 ( TAIF photo!) .

VIETNAM. [Nghệ An Province]: Annam, Vinh, in ricefield, 23 January 1909, W. Micholitz s.n. ( K!). [Khánh Hòa Province]: Annam, Nha-trang [Nha Trang] and vicinity, 11–26 March 1911, C. B. Robinson 1054 ( K!, NY photo!, P photo!, WAG photo!), Annam, Nhatrang [Nha Trang] et enviros, 04–05 February 1914, A. Chevalier 30427 ( P photo!). Thua-thien [Thừa Thiên Huế Province]: Cau-hai [ C ầu Hai lagoon], dans les sables des dunes [in the sand of the dunes], without date, P. Eberhardt 1362 ( P photo!); Hui [Huế], citadelle, champ du Boi (rare), March–May without year, P. Couderc s.n. (P-04583197 photo!, P-04583197 photo!). [Quảng Ninh Province]: Quang-Yen [Quảng Yên], ricières [rice fields], December 1908, Rotereau s.n. (P-04581087 photo!); Tonkin, Quang Yen, rizières, October 1909, C. d’Alleizette s.n. (P-04583151 photo!). [Bình Thuận Province]: Phanthiết [Phan Thiết], route de Phui-hài, sables humides [wet sands], 05 November 1924, F. Evrard 1715 ( P photo!). [Đà N ẵng municipality]: Tourane [Đà N ẵng], January 1837, M. Gaudichaud 170 ( P photo!); Annam, Tourane [Da Nang], common in the dunes near the sea, May–July 1927, J. & M. S. Clemens 3032 ( IBSC photo!, MO photo!, P photo!, WAG photo!). [Bà R ịa-Vũng Tàu Province]: Cap St. Jacques [Vũng Tàu], 19 October 1919, M. Poilane 616 ( P photo!). [Hanoi municipality]: Jongkin [Tonkin], Env.[irons] de Hanoï [surroundings of Hanoi], rizière [rice field], July 1908, C. d’Alleizette s.n. (P-04583159 photo!). [Phú Yên Province]: Tonkin ( NB), Yên Môi (Vung), 17 November 1889, R. P. Bon 144 ( P photo!). [Quảng Trị Province]: Annam, Province de Quang Tri, Village de An Nha [today a quarter of Gio Linh city], bonds d’une rizière (margins of a rice field), 17 April 1936, Pételot 5718 ( P photo!) .

THAILAND. [Prachuap Khiri Khan Province]: Rachaburi [not corresponding to today’s Ratchaburi Province], Nawng Kae [Hua Hin District], Kao Ta Kiep [Khao Takiap], c. 5 m, 26 September 1927, Mrs. D. J. [= E. E.] Collins 1621 ( P photo!) .

Figures

FIGURE 3. A. Distribution of Drosera margaritacea in the Kimberley Region, Western Australia (all known records of D. finlaysoniana in that range also indicated). B. Global range of D. finlaysoniana. Maps drawn by A. Fleischmann.

FIGURE 4. Lectotype of Drosera finlaysoniana, Wallich Cat. No. 3752 [= G. Finlayson 507, collector denoted only on the duplicate at K-W] (E-00206577). Image kindly provided by the Royal Botanic Garden Edinburgh and available online at: http://data.rbge.org.uk/herb/ E00206577

FIGURE 5. Drosera finlaysoniana. A. habit; note the relatively short, few-flowered inflorescences. B. stem with peduncle and leaf bases; note the sessile leaves lacking any obvious petiole, i.e. the carnivorous tentacles are emergent all the way to the stem. C. pink-petalled flower. D. white-petalled flower. E. inflorescence. F. close-up of stamens. A, C, D from Keep River National Park, Northern Territory, 09 July 2014, photographs by A. Fleischmann. B from Cue, Western Australia, 13 July 2020, photograph by T. Krueger. E, F from near Indee Station, Western Australia, 20 August 2014, photographs by T. Krueger.

FIGURE 6. Comparison of herbarium specimens of Drosera margaritacea (left) and D. finlaysoniana (two plants on the right). Note the differences in inflorescence size, peduncle length and numbers of flowers per inflorescence. These features allow quick identification of herbarium material without microscopic indumentum inspections. Inset shows macro-photograph of stalked-milky white glands on petiole of D. margaritacea. Note that these glands retain their shape in dried material but lose stickiness (as tested with steel needle visible on right edge of this inset). Left specimen T. Krueger 7 (holotype; PERTH), right specimens T. Krueger 6 (PERTH, MIN). Photographs by T. Krueger.

FIGURE 9. Seed comparison of Drosera margaritacea (left: A, C, F, G) and D. finlaysoniana (right: B, D, E, H, I). A Trent River Valley, Yampi Peninsula, Kimberley, Western Australia (A. Lowrie s.n.). C, F, G Type locality of D. margaritacea, Kimberley, Western Australia (T. Krueger 7) B, H, I Keep River, Northern Territory, Australia (A. Lowrie s.n.). D Fujian, China (P.E. Chen 2491). E Hsinchu, Taiwan (from cultivated plant). Photographs and SEM-images by A. Fleischmann.