A New and Endangered Species of Decaspermum (Myrtaceae) from East-Central Queensland Neil Snow Department of Biological Sciences, University of Northern Colorado, Greeley, Colorado 80639, U.S.A. [email protected] Gordon P. Guymer Queensland Herbarium, Brisbane Botanic Gardens Mt. Coot-tha, Mt. Coot-tha Road, Toowong, Queensland 4066, Australia ABSTRACT. The new species Decaspermum struc¬ more characters by ordinary morphological means koilicum N. Snow & Guymer is described from (Snow, 1997). The characters studied overall are Queensland. It is distinguished from Decaspermum similar to those in Snow and Guymer (1999). humile (G. Don) A. J. Scott in Australia by its nar¬ rower and more acute leaves, shorter petioles, and Decaspermum struckoilicum N. Snow & Guy¬ unlobed mature fruits. The new species lacks the mer, sp. nov. TYPE: Australia. Queensland: “vertical false septum” that has been reported to Port Curtis District, Struck Oil, 6 km E of occur in the middle of each locule between seeds Mount Morgan, 29°39'S, 150°28'E, 14 Nov. in Decaspermum, and which has been used in part 1987, N. Hoy s.n. (holotype, BKI [AQ to diagnose Decaspermum from related genera. In¬ 455657]; isotypes, B1SH, BRI, GREE, K, stead, the three seeds that typically occur per loc¬ LAE, M0, NSW). Figure 1. ule in the mature fruit are completely surrounded by an encapsulating membrane. Typically, seeds Decaspermum sp. “Mt. Morgan” in Henderson within the membrane are weakly fused and lack (1997). any intervening tissue between them. A key is pro¬ vided to separate the new species from Decasper¬ Haec species a Decaspermo humili foliis ellipticis la- mum humile. tioribus apice acutis non acuminatis supra plerumque he- Key words Australia, Decaspermum, endan¬ betatis marginibus planis, petiolo 1.5—4.5 mm longo, hy- panthio praecipue basi sericeo, fructa maturitate in gered, Myrtaceae, Myrtinae, Queensland. sectiona transversali circular! distinguitur. Decaspermum J. R. Forster & G. Forster is a ge¬ Erect multi-stemmed shrubs or small trees, up nus of approximately 30 species with fleshy fruits to 4 m tall. Bark smooth to somewhat flaky, gray or in Myrtinae (Myrtaceae) that ranges from Indoma- brown. Branchlets of current year round, gray to lesia to at least Tahiti (Snow, 2000). Relatively little reddish brown, smooth, sparsely short sericeous; oil attention has been focused on the genus since the glands indistinct, sparse to common. Leaves dis- revisionary work of Scott (1979a, 1979b, 1980), colorous, matte or slightly glossy above, matte be¬ apart from a generic transfer by Parnell and Nic low, decussate, opposite, ± evenly distributed Lughadha (1992) and observations by Chang and along branches, coriaceous. Leaf axils bearing 2 to Miau (1982) regarding its occurrence in China. In several setose, ferrugineous hairs. Petioles glabrous Australia the genus is represented by two species, to sparsely sericeous, 1.5—4.5 mm long, glandular D. humile (G. Don) A. J. Scott and the new species when young and becoming somewhat rugulose with described herein, D. struckoilicum N. Snow & Guy¬ age, olive-green to reddish, smooth to channeled mer. above. Leaves elliptic, pinnately nerved, 18—55 X Descriptions are based primarily on herbarium 10—35 mm, base cuneate, apex acute, uppermost material (BRI, CANB, NSW) but include observa¬ tip pointed to mucronate, margins flat; upper sur¬ tions from wild and cultivated specimens. We use face glabrous, oil glands prominent, visible without a general lineage concept (de Queiroz, 1998), in magnification or requiring 10X magnification, which species are hypothesized to represent toko- dense, midvein flush; lower surface glabrous, oil genetically closed genealogical lineages (Frost & glands prominent without magnification, dense, Kluge, 1994; Davis, 1997) diagnosable by one or midrib slightly raised, lateral veins not visible or Novon 11: 475-478. 2001. 476 Novon Figure I. Decaspermum struckoilieum N. Snow & Guymer. —Center, (lowering branchlet (l). Hoy 3). —Top left, flower (/V. Hoy AQ 455657). —Top right, mature fruit (D. Hoy AQ 476400). —Center right, encapsulating membrane of seeds (D. Hoy AQ 476400). —Bottom left and right, mature seeds (D. Hoy AQ 476400). (All vouchers at BRI.) indistinct, intramarginal veins not visible or indis¬ extending beyond ovary apex, oil glands common tinct, up to 1.2 mm from margin. Inflorescence ter¬ to dense. Calyx lobes 4 or 5 (sometimes both on a minal or axillary, solitary or paired, paniculate (bot- single plant), fused proximally beyond ovary, sep¬ ryoid or metabotryoid sensu Briggs & Johnson, arate in bud, mostly greenish or somewhat petaloid 1979), anthopodia occasionally present; peduncles on margins, broadly ovate* to rounded, apex obtuse, subtending each flower rigid, 2.5—4.5 mm long, free portions of lobes 1.2-1.5 mm long, glabrous to sparsely sericeous. Bracteoles 2. linear to narrowly sparsely ciliate, glabrous below, persistent in fruit, triangular, 1.0-1.4 mm long, 0.3—0.5 mm wide, as¬ erect. Petals 4 or 5, yellowish white, widely ovate cending to erect, shorter than base of sepal lobes, to oblate, 3.0—3.5 X 2.5—3.5 mm. glabrous to mi¬ sparsely sericeous, soon deciduous in flower. Hy- nutely c iliate, glabrous below, oil glands common. panthium cupulate, smooth, 1.0—1.7 mm long, Stamens 16 to 25, in I to 3 whorls, included, fila¬ sparsely sericeous (particularly at base), tube not ments up to 3.5 mm long; staminal disk glabrous; Volume 11, Number 4 Snow & Guymer 477 2001 Decaspermum from Queensland ovary apex glabrous; anthers subglobose, dorsifix- separated easily. When the encapsulating mem¬ ed, versatile, 0.5—0.8 mm long, dehiscing via lon¬ brane is removed from the mature fruit, the re¬ gitudinal slits, eglandular. Style 2.5-3.5 mm long, maining hypanthium wall is thin, suggesting its tis¬ glabrous; stigma terete to slightly capitate by virtue sue may be derived at least partially from the one of subapical constriction of style. Fruit a soft berry, or more layers of the ovary wall. A more detailed subglobose to globose, base rounded, up to 7.5 mm anatomical study of this variation in tissue structure long and 8.5 mm wide, glabrous, dark bluish black is needed and might enlighten relationships in De¬ at maturity. Ovaries 3- to 4-locular; placenta capi¬ caspermum (Snowy, 1999). tate, axile; ovules usually 3(2) per placenta, in I horizontal row. the seeds of each locule becoming Key to Australian Species of Decaspermum surrounded by an encapsulating membrane in ma¬ 1. Leaves elliptic, apex acute to mucronate, upper ture fruit (Snow, 1999, 2000); seeds up to 8 in ma¬ surface mostly matte, margins flat; petioles 1.5- ture fruit, rounded to somewhat reniform, flattened, 4.5 mm long; hypanthium sericeous mostly at hase; mature fruit lacking constrictions along loc¬ dark brown, 2.2-3.7 mm long, adjacent seeds ular walls in cross section . I), struckoilicum weakly fused, long ( = embryonic) axis oriented 1'. Leaves narrowly elliptic, apex acuminate, upper vertically, outer testa hard, bony; cells of testa rel¬ surface mostly glossy, margins slightly recurved; atively large and irregularly elliptic. Embryo slight¬ petioles (3-)4—7 mm long; hypanthium sericeous throughout; mature fruit somewhat constricted ly curved, oil glands absent, starchy, endosperm ab¬ along locular walls in cross section . ... D. humile sent, hypocotyl relatively thin and not swollen at tip and held on same plane as cotyledons, cotyle¬ Paratypes. AUSTRALIA. Queensland: Port Curtis dons straight, shorter than hypocotyl, folded back¬ District, Struck Oil, 6 km E of Mt. Morgan, 23°39'S, I50°28'E, 18 Nov. 1989, Forster PIF 4984 (BRI, L), Hoy ward sharply toward hypocotyl. s.n. (BRI AQ 476400 + spirits, MEL, QRS); Struck Oil via Ml. Morgan, 23°4-'S, 150°2-'E, 22 Oct. 1984, Hoy 3 The specific epithet refers to the town of Struck (BUI); Struck Oil, property of D. McDonald, 23°37'S, Oil, around which the new species occurs. 150°27'E, 7 Feb. 1997, Forster et al. PIF20268 (Bill). Phenology. Flowering in October and Novem¬ Acknowledgments. We thank the curators of ber; fruiting November through February. Bill, CANB, and NSW for loans of specimens; Les Decaspermum struckoilicum is restricted to the Pedley and Roy Gereau for assistance with the Lat¬ small town of Struck Oil and vicinity, roughly 30 in diagnosis; Will Smith for the illustration; and P. km south of Rockhampton in east-central (Queens¬ Wilson and L. Landrum for constructive reviews. land. It occurs in semi-evergreen vine thickets on Research was supported by grants from the Austra¬ reddish or chocolate soils, often in disturbed areas, lian Biological Resources Study from 1997 to 1999. and at elevations up to 300 m. The new species is fhe senior author thanks the University of Northern only known from six collections and is currently Colorado for granting a leave of absence to finish listed as Endangered under the Queensland Nature this project. Conservation Act of 1992. It also should be con¬ sidered Endangered under IUCN standards follow¬ Literature Cited ing criteria B1 and C2a (Species Survival Commis¬ Briggs, B. A & L. A. S. Johnson. 1979. Evolution in the sion, 1994). Little is known at tbe current time Myrtaceae—Evidence from inflorescence structure. regarding the number or sizes of populations or Proc. Linn. Soc. New South Males 102: 157—256. whether the populations are stable. As such, a de¬ Chang, H. T. & R. H. Miau. 1982. Additions to the Myr- tailed survey of its status should be a high priority taceous flora of China. Acta Bot. Yunnan. 4: 17—25. Davis, J. I. 1997. Evolution, evidence, and the role of for conservation assessments. species concepts in phylogenetics. Syst. Bot. 22: 373— Snow (1999) discussed the inaccuracy of the 403. term “vertical false septum” (Scott, 1979a: 432, Frost, I). R. & A. G. Kluge. 1994. A consideration of 1979b: 59) as a diagnostic character for the genus. epistemology in systematic biology, with special refer¬ The mature fruit of Decapsermum struckoilicum has ence to species. Cladistics 120: 259—294. Henderson, R. J. F. 1997. Queensland Plants: Names and no septum located in tbe middle of each locule. Distribution. Queensland Department of Environment, Rather, the three seeds that typically occur per loc¬ Brisbane. ule in the mature fruit are completely encapsulated Parne II, J. & E. Nic Lughadha. 1992. Notes on Thai Myr¬ by a moderately thick tissue layer, but no tissue taceae. Kew Bull. 47: 703-706. Queiroz, K. de. 1998. The general lineage concept of spe¬ intervenes between seeds in an individual locule. cies and the defining properties of the species category. Snow (1999) tentatively designated this tissue as Pp. 49—89 in R. A. Wilson (editor). Species: New In¬ the encapsulating membrane (see Fig. 1). Adjacent terdisciplinary Essays. MIT Press, Cambridge, Massa¬ seeds in each locule are weakly connate but are chusetts. 478 Novon Scott, A. J. 1979a. A revision of Rhodamnia (Myrtaceae). -. 1999. Notes on generic concepts in Rhodomyrtus, Kew Bull. 33: 429-459. Archirhodomyrtus, Decaspermum, and Pilidiostigma -. 1979b. The Austral-Pacific species of Decasper¬ (Myrtaceae). Austral. Syst. But. Soe. Newslett. 99: 5—7. mum (Myrtaceae). Kew Bull. 34: 59-67. -. 2000. Systematic conspectus of Australasian -. 1980. A synopsis of Decaspermum (Myrtaceae) Myrtinae (Myrtaceae). Kew Bull. 55: 647-654. in Southeast Asia and China. Kew Bull. 35: 403— -& G. P. Guvmer. 1999. Systematic and cladistic 411. studies of Myrtella F. Muell. and Lithomyrtus F. Muell. Snow, N. 1997. Application of the phylogenetic species (Myrtaceae). Austrobaileya 5: 173-208. concept: A botanical monographic perspective. Austro- Species Survival Commission. 1994. IUCN Red Cist Cat¬ baileya 5: 1-8. egories. IUCN Council, Gland.