Sphagneticola annua Orchard, 2013

Orchard, A. E., 2013, A new species of Sphagneticola (Asteraceae: Ecliptinae) from Indonesia, Blumea 58 (1), pp. 49-52 : 49-52

Sphagneticola annua Orchard , sp. nov. — Fig. 1

The genus Sphagneticola was described by Hoffmann (1900) with a single species, S. ulei O.Hoffm. However , Hoffmann’s species had previously been described as Silphium trilobatum L. by Linnaeus (1759), based on a description and plate in Plumier (1757). The equivalence of these two descriptions was not recognised for many years. In the meantime, Silphium trilobatum was transferred to a number of different genera: Wedelia , Stemmodontia , Thelechitonia and Complaya (see Strother (1991), Robinson & Cuatrecasas (1992) and Pruski (1996) for a summary).

Sphagneticola was resurrected by Pruski (1996). He recognised four species: S. brachycarpa (Baker) Pruski , S. calendulacea (L.) Pruski, S. gracilis (Rich.) Pruski and S. trilobata (L.) Pruski. The genus was defined as stoloniferous herbs rooting at the nodes, stems sympodial with terminal capitula displaced laterally, ray laminas abaxially glandular, anther appendages black and ovate, achenes tuberculate and lacking well-developed carpopodia, elaiosomes and pappus awns, and often with the body of the achene extended upwards as a collar. Sphagneticola brachycarpa is confined to the northern part of South America, S. gracilis to the Caribbean, S. calendulacea to the Indian subcontinent, East Asia and Malesia, and S. trilobata is apparently native to the Neotropics, but is widely cultivated almost throughout the tropics and has become naturalised in parts of Africa, eastern Australia, Malaysia, the Pacific and parts of southern United States of America.

While working on Australasian and Malesian taxa of the Wedelia / Melanthera / Wollastonia complex, I received on loan a specimen from Wetar Island, Indonesia, which differed from all Malesian wedelioid taxa. It does, however, agree with the critical characters of Sphagneticola in most respects, but differs in being an erect annual rather than prostrate and rooting at the nodes. It is described below as the fifth species of that genus. As diagnostic illustrations of the taxa of Sphagneticola are relatively scarce, the new species is illustrated, along with the other two species of Sphagneticola found in Asia / Malesia.

1 c/o Australian Biological Resources Study, GPO Box 787, Canberra ACT 2601, Australia; e-mail: [e-mail].

Type: C. R.Dunlop 9641 & G.J.Leach (holo DNA 69580; iso BO?, n.v.),

Indonesia, Wetar Island , Kali Kuning River, 15 May 1993 .

Erect slender annual herb to 40 cm tall; stems oppositely branch- ed, sulcate, softly villous. Leaves opposite, petiolate; petiole 1 cm long; lamina ovate, 5 –7 cm long, 2.5 – 5 cm wide, triplinerved, shortly serrate, soft herbaceous,?succulent, finely appressed pilose; uppermost leaves lanceolate, entire. Capitula terminal, in dichasial groups of 3(–5), on peduncles 15–40 mm long; involucral bracts in 2 series, lanceolate to narrowly ovate, 8 –10 mm long, subequal, pale green, soft, acute, sparsely and softly semiappressed pilose. Ray florets c. 6, pistillate; lamina yellow, oblong to ovate c. 5 mm long, 2.5 mm wide, 3-lobed, weakly striate, with a short tube, sparsely glandular and hairy on abaxial surface, with glands tiny, sessile, globular, golden; ovary obcuneate, 3-angled, with angles extended above as rays which support a laciniate, sparsely fimbriate membranous ‘skirt’ hiding the pappus and corolla tube. Disc florets c. 15, bisexual but probably functionally staminate; corolla creamy white to yellow, 5-lobed, with lobes spreading, lobes and tube glabrous; anthers and appendages black; anther tails very short; filament collar slightly swollen; style densely papillose distally; style arms remain within floral tube,?fused; pappus a short serrulate corona with c. 2 teeth slightly extended as ‘awns’. Paleae linear, 4– 4.5 mm long, somewhat conduplicate, acute, entire, with a well-defined midrib, not carinate, shortly scabrous on midrib and margins distally. Achene grey-black, body obcuneate, 4 mm long, 2 mm wide, compressed, 3-angled, coarsely tuberculate; angles extended apically to support a laciniate membranous ‘skirt’; exocarp thinly spongy; awns 0.

Ecology — Found on a shoreline, under a dense shrubby layer of Mussaenda regrowth, in clayey sand. The leaves in the type specimen have dried tissue-paper thin, but in life were probably at least semisucculent.

Notes — The generic placement of this species presents some difficulties. It clearly belongs in subtribe Ecliptinae , but if studied within the overview of the subtribe presented by Panero (2007), it keys to Baltimora , a genus of two species of the Neotropics, mainly on account of its black anthers and functionally staminate disc florets. Baltimora was revised by Stuessy (1973), who recorded that one species, B. recta L. was also known from Java. Stuessy provided good descriptions and

© 2013 Naturalis Biodiversity Center illustrations of both species of Baltimora , and it is clear that, while the new species resembles both of the Baltimora species in leaf morphology and general habit, the achene morphology is quite different. The achene in Baltimora is triquetrous, with usually pronounced vertical horns or wings on the distal part of the ribs, and the achene is shortly puberulent near the apex. This is quite different to the achene in S. annua , where the body of the achene is extended upwards into an inverted ‘skirt’ supported by three thickened rays, and there are no vertical wings. The achenes in S. annua are glabrous. In these achene features S. annua is much more akin to that of S. trilobata . Other characters separating S. annua from Baltimora species are the glabrous corolla lobes in its disc florets, an ovary in the disc florets exceeding 1 mm in length and paleae with a well-defined midrib which is shortly scabrous.

Another genus in subtribe Ecliptinae found geographically adjacent to S. annua is the northern Australian endemic Pentalepis F.Muell. , with six species, and resembling S. annua in having functionally staminate disc florets. This genus has recently been revised ( Orchard 2012a). However, Pentalepis differs from S. annua in consistently having five involucral bracts in a single series, each bract subtending a ray floret, and disc florets with yellow to pale brown anthers (anther appendages always yellow). The achenes are compressed, often cucullate, and usually winged, and the pappus is a short cup with usually two short soft awns.

Another ecliptoid coastal genus in the Indo-Pacific region is Blainvillea Cass. also recently revised ( Orchard 2012b). This genus of four species can be eliminated from consideration here, as it has consistently bisexual, fertile disc florets, a pappus of scales and/or rigid awns, and paleae which are distinctively broad, truncate and apically laciniate/ciliate. The achenes vary from obcuneate to subcylindrical, and never have a raised collar or inverted ‘skirt’ apically.

The genus Wedelia Jacq. has also been reported from the Indo-Pacific. This generic name has been applied to a dis- cordant group of pan-tropical taxa, and in its current sense is almost certainly polyphyletic. A review of the group, including Wollastonia DC. ex Decne. , Melanthera Rohr , and other taxa has recently been published ( Orchard 2013). None of the 100+ species in this complex has an achene morphology resembling the skirted form found in S. annua , and most have bisexual, fertile disc florets.

This species matches Pruski’s (1996) diagnostic characters for Sphagneticola in terminal capitula (but not displaced laterally by sympodial stem growth), ray laminas abaxially glandular, anther appendages black and ovate, achenes tuberculate and lacking well-developed carpopodia, elaiosomes and pappus awns, and often with the body of the achene extended upwards as a collar. It differs mainly in being an erect annual rather than a prostrate perennial rooting at the nodes, and in apparently having functionally staminate disc florets. The collar at the apex of the achene, which is well-developed in S. brachycarpa , S. gracilis and S. trilobata , but almost absent in S. calendulacea , is represented in S. annua by a more membranous ‘skirt’ supported by three thickened rays arising from the apices of the achene angles. The corky achene exocarp of S. trilobata is also present in S. annua , but is much thinner. The long papillae on the adaxial side of the disc floret lobes in S. trilobata and some other species are absent in S. annua , the disc floret corolla being entirely glabrous. The new species is thus assigned to Sphagneticola as it more comfortably fits the diagnostic characters of that genus, rather than Blainvillea , Pentalepis , Wollastonia or Wedelia s.l.

There is a note on the holotype sheet in DNA stating that a duplicate was sent to BO, and if so, this would be an isotype. The duplicate was not seen during this study .

As detailed descriptions and illustrations of Sphagneticola species are scarce, comparative illustrations of the other two Malesian / Asian species of this genus are provided (Fig. 2, 3).

Figures

Fig. 1 Sphagneticola annua Orchard. a. Lower leaf; b. upper leaf; c. palea, dorsal view;d. palea, lateral view; e. outer involucral bract; f. inner involucral bract; g. ray floret; h. disc floret; i. stamens; j. young style (from within anther tube); k. achene; l. longitudinal section of achene (all: C.R.Dunlop 9641 & G.J.Leach, holo, DNA).