Studies on Schismatoglottideae (Araceae) of Borneo LXX — New colonial species for the Schismatoglottis [Calyptrata Clade] from Sarawak

Three new colonial species of Schismatoglottis Calyptrata clade are described and illustrated from Sarawak and compared with the four pre-existing morphologically similar species occurring in the state. A modified description of Schismatoglottis niahensis is provided to correct a previous misinterpretation of the stem architecture. All seven recognized species are illustrated from living plants.

INTRODUCTION Previous comprehensive regional accounts for Schismatoglottis (Hay 1996;Hay and Yuzammi 2000) provided an excellent baseline to undertake further study. Preliminary work on the Schismatoglottis Calyptrata clade for Sarawak (Wong 2012;Wong et al. 2016) recognized six species, four of which are stolonifeous-colonial, and of which Schismatoglottis baangongensis S.Y.Wong, Y.C.Hoe & P.C.Boyce (Wong et al. 2016: 80) was newly described and S. muluensis M. Hotta (Hotta 1966: 235) resurrected from within S. calyptrata Zoll. & Moritzi (Moritzi 1846: 83), with the latter treated as absent from Sarawak, and with its occurrence on Borneo considered to be doubtful.
Subsequently Wong & Boyce 2020a) defined S. calyptrata as restricted to Maluku (the Type is from Pulau Ambon) through the Philippines archipelago and possibly occurring as far north as Lanyu Do (Taiwan) [but see Schismatoglottis kotoensis (Hayata) T.C.Huang, J.L.Hsiao & H.Y.Ye (Huang et al. 2000: 305)], eastwards through New Guinea and the Bismarck Archipelago to the Solomons. Determining to what extent Schismatoglottis calyptrata sensu strictiore occurs in the eastern part of this area still requires much work (see Hay in Hay & Yuzammi 2000;Wong et al. 2018). Implementing narrower species definitions means that plants formerly treated as S. calyptrata in Sarawak are new species that require publication for Borneo. In many instances the material to hand is inadequate to allow publication at the present time. This paper deals with three novelties for which we have complete material.
As noted in previous papers (e.g., Hay 1998;Kartini et al. 2015;Wong & Boyce 2020b) the extraordinarily complex surface geology of the island of Borneo is enormously important in the separation of species in aroid genera such as Homalomena, Schismatoglottis, and Alocasia, among others. Geology in this paper is specified based on Hutchison (1989Hutchison ( , 2005 and Tate (2001).

Diagnosis
Schismatoglottis adducta is most similar to S. muluensis by the presence of an elongated partially naked interstice separating the pistillate and staminate florets, and scattered ascending-clavate waxy white pistillatezone staminodes, but readily distinguished by the blunt bullet-shaped spadix appendix (in S. muluensis the appendix cylindrical) two thirds the length of the staminate zone (in S. muluensis the appendix twice as long as staminate zone), by the pistillate floret zone comprising about one half of the spadix length (in S. muluensis the pistillate floret zone comprising slightly less than one third of the spadix), and dorsally fused to the spathe for about one third its length (vs not at all fused in S. muluensis). A bullet-shaped appendix occurs in S. giamensis and S. roh, from both of which S. adducta is distinguished by the elongated naked (vs abbreviated staminode-covered) interstice, and by having only the basal third (vs as least half) of the pistillate floret zone adnate to the spathe.

Etymology
From Latin adductus -stretched, used in reference to the elongated distal portion of the sterile interstice separating the zones of pistillate and staminate florets.

Distribution
Widespread and locally abundant along the banks of the Batang Lupar and Sungai Raya near Sri Aman.

Ecology
Occurring in deep alluvial sandy clays over Eocene or Cretaceous sediments at low altitude under moist alluvial riverine forest.

Notes
Pollination biology data for Schismatoglottis adducta (and the other species covered here) are presented in Hoe et al. (2018). In summary pollination involves thermogenesis and floral odour production and consists of a biphasic pattern of thermogenesis in the appendix and the staminate zone with the first temperature peak occurring during pistillate anthesis and the second during staminate anthesis. During inter-anthesis, thermogenesis ceases, with the ambient temperature remaining higher than that of the spadix. Methyl ester-3-methyl-3-butenoic acid is the single major compound in the floral scent profile, and the appendix the main olfactory structure. Colocasiomyia flies are the primary pollinators with Cycreon (Hydrophilidae) beetles secondary pollinators for all except S. muluensis for which Atheta (Staphylinidae) beetles are the primary pollinators.

Etymology
Derived from the name of the type locality plus the Latin suffix, -ensis, to indicate origin.

Distribution
Schismatoglottis baangongensis is known from the type locality and its vicinity.

Ecology
Terrestrial in perhumid lowland forest associated with (but never occurring epilithically on) Jurassic Karst limestone, often forming dense stands along trails bordering to small streams, 70-75 m asl.

Diagnosis
Schismatoglottis giamensis most closely resembles S. baangongensis and S.roh by the bullet shaped appendix, but is distinguished among the three by having almost the entire pistillate floret zone dorsally adnate to the spathe (vs at most half pistillate zone dorsally adnate). Schismatoglottis giamensis is further distinguished from S. baangongensis and from S. roh by the larger stamens with thecae having a thickened rim, and additionally from S. baangongensis by the pistillate zone with the lower part narrowing and then the base expanding at the junction of pistillate zone the interstice (vs pistillate zone uniformly narrowing all the way to the base).

Etymology
Derived from the name of the type locality plus the Latin suffix, -ensis, to indicate origin.

Distribution
Known only from the type locality.

Etymology
Derived from the name of the type locality plus the Latin suffix, -ensis, to indicate origin.

Distribution
Endemic to Mulu.

Ecology
Schismatoglottis muluensis is restricted to shaded damp Karst limestone formations at Mulu N.P., where it is notably abundant along the trail to Deer Cave occurring epilithically under perhumid lowland tropical forest between 40 and 75 m asl.

Description
Robust herb 70 cm tall. Stem erect and largely epigeal, suckering, comprised of greatly elongated hapaxanthic modules, to 30 cm tall × 5 cm diam.; internodes 2 cm long. Leaves few together; petiole 40 cm long, sheathing in the lower ⅓-⅔; wings of sheath tapering, fully attached; blade sagittate, mid-green adaxially, paler below, 28-35 cm long × 13-22 cm wide, widest at or near base, the base cordate with rounded posterior lobes 7-9 cm long; midrib flush with the lamina (dry), stout and broad, with 13 rather stout, adaxially pale green primary lateral veins on each side, irregularly alternating with lesser interprimaries, sometimes branched especially in the lower part of the anterior lobe, diverging at 70° and almost straight for most of the way to the margin before deflecting distally; secondary venation rather obscure adaxially and abaxially, arising from the midrib and the primary veins; tertiary venation obscure. Blooms to 4 together, subtended by short cataphylls except the first subtended by a cataphyll reaching to half way along the spathe and bearing a reduced petiole and blade; peduncle 13-15 cm long. Spathe 11-15 cm long; lower spathe 4-5.5 cm long, narrowly ovoid, differentiated from the limb by a sharp constriction; limb ovate, 7-10 cm long, slightly inflated over the appendix, finally acuminate for 2 cm, caducous. Spadix 9 cm long, narrowly hourglass-shaped; female zone 3.8 cm long, adnate to the spathe in the lower 1.2 cm, 8 mm diam. in the middle, distally conoid and apically 3 mm diam.; pistils crowded, narrowly cylindric (especially near the base of the female zone, distally somewhat lower and thicker), 0.5 mm diam.; stigma sessile, button-like, about the same diameter as the ovary; interpistillar staminodes scattered among the pistils, more crowded in the distal part of the female zone, long-stalked, apically abruptly clavate and flat-topped, 1.5 times the height of the ovary; sterile interstice 2-3 mm long, slightly obconic, 3-4 whorls of sterile stamens drying very dark brown, lying level with the mouth of the lower spathe; male zone obconic, 2.8 cm long, distally 1 cm diam.; stamens densely crowded, 0.5 mm across, dumbbell-shaped with large round pores and the connective slender and raised into a short broadly triangular point somewhat off-centre; appendix more or less bullet-shaped, at the base slightly but abruptly wider than the top of the male zone, 1.2 cm diam., then somewhat tapering and finally obtuse; staminodes of appendix columnar, flat-topped and irregularly polygonal with rounded angles, 0.5 mm diam. Infructescence not observed

Etymology
Derived from the name of the type locality plus the Latin suffix, -ensis, to indicate origin.

Distribution
Known only from Niah National Park.

Ecology
At the base of limestone bluffs surrounded by swamp forest at low altitudes.

Notes
Hay (Hay & Yuzammi 2000) described the stems of S. niahensis as pleionanthic, whereas in fact they are hapaxanthic but unique in the clade for having much  of the stem epigeal, thus giving a first impression of a pleionanthic shoot. Pollination data presented in Hoe et al. (2018), are under the name "S. pseudoniahensis", a manuscript name we utilized at the time of the study when we had yet to fully understand the identity of the plants occurring at Niah.  (Figures 11, 12 and 14F).

Diagnosis
Schismatoglottis roh resembles both S. baangongensis and S. giamensis by the bullet shaped appendix but is distinguished from both by very densely packed staminate florets, and by the much more abundant pistillate floret staminodes that are each about twice as long as the height of the pistil and truncate-topped (vs at most half as tall again as the pistils and rounded-clavate).

Etymology
Coined from the Malay language word for a spirit, roh, used by way of allusion to the type locality, Gua Peri-peri, Fairy Cave.

Distribution
Restricted to Cretaceous Karst in the Bau area of Kuching.

Ecology
Occurring in light to medium shade in alluvial soils at the base of Karst stacks, often near to.

Description
Small mesophytic clump-forming herb to 25 cm tall. Stem hypogeal, hapaxanthic, 0.5 cm diam. Leaves 5 together in each crown; petiole to 20 cm long, sheathing in the lower third; petiolar sheath wings fully attached, tapering but apically truncate; blade narrowly ovate, brilliant green with a rubbery thinly subsucculent texture, 16 cm long × 7 cm wide, base cordate with rounded posterior lobes to 1.5 cm long, tip acute; midrib rather prominent; primary lateral veins 7 on each side, irregularly alternating with lesser interprimaries and diverging at 60-80°; secondary venation mostly arising from the midrib, some from bases of primary veins; tertiary venation forming an indistinct tessellate reticulum on both surfaces (visible in dry material). Blooms 2-3 together; peduncle fleshy, 4 cm long, mostly hidden by sheaths of subtending leaves. Spathe 9 cm long; lower spathe narrowly ovoid, 4 cm long, differentiated from limb by an abrupt constriction; limb 5 cm long, very broadly ovate, inflated over staminate zone and appendix and then acute, finally acuminate for 1 cm, greenish, caducous. Spadix 5-6 cm long, sessile, more or less hourglass-shaped; pistillate flower zone about half the length of spadix, 3 cm long, adnate to spathe in lower 2/3, 7 mm diam. in middle, then somewhat conic and attenuate to 5 mm diam.; pistils somewhat lax, more so in distal part of pistillate zone, bottle-shaped, bright green, 1 mm diam. in lower part of zone, 2 mm diam. higher up; interpistillar staminodes scattered among pis-tils, more or less mushroom-shaped, equalling ovaries in height, 0.5 mm diam.; sterile interstice ill-defined, upper 4 mm of pistillate zone thickly attenuate and occupied by mixed staminodes, stamens and abortive(?) pistils; staminate flower zone 1.4 cm long, subcylindric, 5 mm diam. in lower 5 mm (held within lower spathe chamber), remainder abruptly obconic, to 9 mm diam. and exserted from lower spathe chamber; stamens crowded, truncate, hourglass-shaped, with connective thin and not at all elevated above thecae, 1 mm across; appendix shortly bullet-shaped, base slightly but abruptly wider than top of staminate flower zone, 1 cm wide at base, 1.3 cm long; appendix staminodes flat-topped, centrally impressed, irregularly polygonal, 0.5-0.7 mm diam., dull medium yellow. Fruit unknown.

Etymology
Named for the peculiarly brilliant green leaf blades.

Distribution
Schismatoglottis viridissima occurs in NW Sarawak and Kalimantan Barat on acidic geologies.

Ecology
Terrestrial in moderate to light shade under perhumid lowland to upper hill forest on granites, or sandstones; 10-940 m asl. The Type locality is granite while elsewhere populations of what appears to be the same or at least a remarkably similar species occurs on sandstones (e.g., Kubah N.P, and Gunung Serembu).