Boyce, P.C. & Wong S.Y. Lost Aroids: on the Taxonomic Importance Of

96 AROIDEANA, Vol. 35 Lost Aroids: On the taxonomic importance of relocating poorly collected species Peter C. Boyce Pusat Pengajian Sains Kajihayat [School of Biological Sciences] Universiti Sains Malaysia 11800 USM Pulau Pinang, Malaysia [email protected] Wong Sin Yeng Department of Plant Science & Environmental Ecology Faculty of Resource Science & Technology Universiti Malaysia Sarawak 94300 Kota Samarahan, Sarawak, Malaysia [email protected] ABSTRACT Aroids, perhaps by reason of their often originating from almost inaccessible tropi- Aridarum montanum Ridl. and Piptos- cal forests, are host to a remarkable number patha insignis N.E.Br. (Araceae: Schisma- of such ‘lost’ species. Remarkable, too, is toglottideae), aroids originating from Bor- that quite some number of long-lost species neo that are each known from a single has been re-found over the past 20 years. collection, are discussed and illustrated. Of particular note [with the period ‘‘lost’’ in The history of their discovery is reviewed, together with what is known or speculated years] are: Gearum brasiliense N.E.Br. of their ecology. The biological significance [150 years] (Mayo et al., 1994), Mangonia of the collection locality of A. montanum is tweediana Schott [142 years] (Bogner & highlighted. The species’ individual impor- Marchesi, 2000), Zomicarpella maculata tance to modern systematics is highlighted. N.E.Br. [116 years] (Bogner, 2007, 2009), and Ulearum sagittatum Engl. [90 years] (Boyce, 1995; Bogner, 1997). KEY WORDS However, many aroid species remain Araceae, Aridarum, Piptospatha, Bor- elusive. Two of these, from Borneo, are the neo, Malaysia, Sarawak, Santubong. subject of this short piece. INTRODUCTION Aridarum montanum Ridl. –Figs.2and3 ‘Lost’ plant species – species tantalizingly In 1909 Cecil Joslin Brooks, a metallur- only known from a single herbarium col- gical chemist and competent amateur lection, or frustratingly from just an old botanist in the employ of the gold-mining illustration, hold an abiding fascination for division of the Borneo Co. Ltd in Sarawak, plant enthusiasts, whether professional bot- collected a diminutive aroid at an unspec- anists or keen hobbyists. The ranks of these ified locality on Gunung (Mt) Santubong, a ‘still lost’ plant species are perhaps no better large sandstone mountain situated on a exemplified than by Archivea kewensis peninsula jutting into the South China Sea Christenson & Jenny (Fig. 1), a Brazilian approximately 35 km north of Kuching, the species (indeed, a genus) known from a state capital of Sarawak. Brooks’ solitary single 19th century watercolour deposited in pressed specimen was subsequently sent to the Herbarium & Archives of Kew Gardens, the British Museum (now the Natural from whence the genus and species epithets History Museum, London), where it was are derived (Christenson & Jenny, 1996). worked up by Henry Nicholas Ridley, with Aroideana arod-35-00-13.3d 3/4/12 11:17:39 96 P. C. BOYCE, S. Y. WONG, 2012 97 Fig. 1. The orchid Archivea kewensis Christenson & Jenny, nomenclaturally perhaps the ‘‘epitomic’’ missing species. E The Herbarium, Library, Art & Archives Directorate, Royal Botanic Gardens, Kew. Reproduced with permission. Aroideana arod-35-00-13.3d 3/4/12 11:17:39 97 98 AROIDEANA, Vol. 35 Fig. 2. Aridarum montanum Ridl. Plate accompanying Ridley’s, 1913 description in The Journal of Botany 51: 201-202. Note the remarkably long needle-like horns on each staminate flower, and the very narrow leaf blades. Fig. 3. Aridarum montanum Ridl. Cecil Joslin Brooks’ collection (now in the Natural History Museum, London – BM) that forms the basis for Ridley’s description, and which serves as the type of Aridarum. This is the only known collection, there being no duplicate specimens and no other known collections. technical assistance from Kew’s Nicholas area; the specific epithet, montanum, also Edward Brown. Ridley (1913) published implies this. However, there is no support- Brooks’ collection as the type of a new ing evidence for a summit-origin of Brooks’ species in a new genus: Aridarum mon- plant, and furthermore all other Aridarum tanum Ridl., contriving the generic name species are rheophytes, to which narrow from Latin aridus (dry) + arum. This, leaf blades are also eminently adapted. It is however, is likely a misnomer based on of more than passing interest to note that Ridley’s belief, presumably derived from Ridley’s handwritten notes on the herbar- the narrow leathery leaf blades being ium specimen indicate that he had origi- adapted for arid conditions and because nally intended to name Brooks’ plant he noted that ‘‘The plant is obviously Siccarum borneense (Latin, siccus 2 dry + xerophytic…’’. Indeed, Ridley noted that arum). the summit of Santubong (which he knew Aridarum montanum is distinct from passably well) was distinctly arid (he used any other aroid species. However, the the term ‘xerophytic’) and from this it may genus for which it is the typical taxon has, be concluded that Ridley believed Brooks’ under combined molecular and morpho- plant to have originated from the summit logical scrutiny, recently been shown to be Aroideana arod-35-00-13.3d 3/4/12 11:17:48 98 P. C. BOYCE, S. Y. WONG, 2012 99 polyphyletic because it comprises species who in 1965 set up two 1.5 acre plots belonging to three not- closely-related (Ashton, pers. comm); and James Aidan evolutionary lineages (Low et al., unpubl. Robb Anderson, (1960s through to the early data). However, without refinding living 1980s), as well aroid specialists such as plants, A. montanum cannot be included in Josef Bogner (several visits in the 1970s and the molecular analysis; attempts to recover 1980s, and again in 2004), and Marc DNA from the herbarium specimen have Gibernau (pollinator-related work in 2004). failed. Thus, although dismembering the Inevitably the lowland forests surround- genus Aridarum into three distinct taxa is ing Santubong are much changed from convincingly supported, a question mark Brooks’ time, but the mountain itself remains over the nomenclature of these remains heavily forested and, away from nascent taxa: the lineage to which A. the two permanent trails, much of it is as montanum belongs is the one of the three inaccessible now as it was then. The which must carry the name Aridarum. authors and their students are frequent Thus aside from being a fascinating and visitors to Santubong, with several projects attractive plant to re-find, the recollection active on the mountain. All, so far, have of A. montanum remains critical to circum- failed to re-find Aridarum montanum, scribing the genus Aridarum. despite searches concentrating along suit- As was remarked earlier, Santubong is able water courses where rheophytic aroids easily accessible from Kuching and has may be expected to occur, as well as long been an attraction to naturalists. observations in the drier areas which Ridley Among those who have collected aroids thought (as we believe, mistakenly) to be there are Odoardo Beccari who explored the habitat in which the original collection the more accessible parts of Santubong in was made. 1866 & 1867. Beccari’s aroid collections were worked up principally by Engler (e.g. Piptospatha insignis N.E.Br. – Figs. 5, 6 Engler, 1879a, 1879b). What is perhaps and 7 remarkable is that that despite being a field botanist of very considerable ability, as well The second ‘lost’ Bornean aroid is as having a more passing interest in aroids, Piptospatha insignis, collected by Frederick Beccari ‘missed’ sampling much of the William Thomas Burbidge, somewhere in aroid flora that he must have encountered. ‘‘North Borneo’’ between 1877 and 1878. Inexplicably, considering that several of his During this period Burbidge was employed Bornean aroid collections indicate he by Messrs. Veitch & Sons, the London and certainly collected in appropriate habitats, Exeter-based nursery, as an explorer for he failed to collect either of the two ornamental plants. Burbidge’s travels and Aridarum species recorded for Santubong adventures, and details of his more notable (the other is A. nicolsonii Bogner Fig. 4), plant introductions for Veitch, which in- nor the one endemic to Matang [A. bor- cluded Nepenthes rajah, are entertainingly neense (M.Hotta) Bogner & A.Hay]. This chronicled in ‘The Gardens of the Sun’ serves well to highlight that many aroids (Burbidge, 1880). are highly localized, a fact not lost on Based on Burbidge’s collection, Brown Burbidge (1880: 341–342). (1879) described Piptospatha insignis as a Henry Nicholas Ridley made at least one new species in new genus. By some degree excursion to Santubong when he visited P. insignis is more enigmatic than is Sarawak six times between 1893 and 1915; Aridarum montanum, not least because it However, as with Beccari before him, and was imported (presumably in commercially again in spite of a particular interest in viable quantities), and came to Brown’s aroids Ridley also failed to gather either of hands from Veitch’s nursery in 1878. It can the Santubong Aridarum. probably be assumed that P. insignis More recently Santubong has been bo- proved sufficiently easy to cultivate in tanically investigated by Peter S. Ashton, ‘‘stove’’ glasshouses of Victorian England Aroideana arod-35-00-13.3d 3/4/12 11:17:56 99 100 AROIDEANA, Vol. 35 Fig. 4. Aridarum nicolsonii Bogner, is endemic to and abundant on Santubong (A) and near-by Bako. It differs from A. montanum by, among other characters: (B) the much larger inflorescences; (C) the much shorter thecae horns; and (D) by the considerably broader leaf blades, and proportionately longer petioles. Overall A. nicolsonii is also a much larger and more robust plant than A. montanum. Scale bars: B 5 2 cm; C 5 5 mm; D 5 2 cm. Images E Peter C. Boyce. Fig. 5. Piptospatha insignis N.E.Br. Plate from The Gardeners’ Chronicle, n.s. 11, 138– 139, Fig.20 (1879). Fig. 6. Piptospatha insignis N.E.Br.

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