FOUR New species OF syzygiUm ( myRtaceae ) FROm aUstRalia

The Australian species of Syzygium Gaertn. and its closer generic relatives were recently revised by Hyland (1983). Hyland accepted five genera within the complex, Acmena DC., Acmenosperma Kausel, Eugenia L., Syzygium, and Waterhousea B. Hyland, treating the Australian species at that time referred to Cleistocalyx Blume within his concept of Syzygium (Hyland, 1983). During work on an account of the generic complex for Flora of Australia (Craven & Matarczyk, in press) it became apparent that to accept the genera recognised by Hyland would require the description of several new genera to accommodate anomalous species. These species were either unknown or inadequately collected when Hyland’s work was published but at least one species treated by Hyland, S. wesa B. Hyland, is incongruent within the genus to which he assigned it. Eugenia and Syzygium often have been treated as congeneric (e.g. Henderson, 1949; Kochummen, 1978) whereas others have maintained them as distinct genera (e.g. Merrill, 1950; Kostermans, 1981). Schmid’s studies of morphological and anatomical data indicated that two separate lineages were involved (Schmid, 1972a, b) and this view has been supported by some recent molecular work. Analyses of matK sequence data and non-molecular data have shown that Syzygium and Acmena form a clade with four other Australasian genera (Anetholea Peter G. Wilson, Osbornia F. Muell., Backhousia Hook. & Harv. and Choricarpia Domin) that is sister to a clade containing both Old and New World genera (Archirhodomyrtus (Nied.) Burret, Pilidiostigma Burret, Rhodamnia Jack, Calyptranthes Sw., Eugenia and Xanthomyrtus Diels, Wilson et al., 2001). While the accumulated evidence that Eugenia and the Syzygium generic complex represent distinct evolutionary lineages may now have resolved that particular issue, there remains considerable uncertainty as to the circumscription of Syzygium. In publications of world-wide scope, Merrill (1950) accepted seven (and tentatively an eighth) genera that belong to the Syzygium complex, Airy Shaw (1966) three, Kausel (1957) ten, and Briggs & Johnson (1979) eight. In more geographically restricted works, often there has

been considerable variation as to which generic segregates are accepted.In a study of Australian species, Hyland (1983) recognised Acmena, Acmenosperma, Syzygium (incl.Cleistocalyx) and a fourth genus, Waterhousea, an Australian endemic.In contrast, in an account of the syzygioid species in Fiji, Smith (1985) recognised Cleistocalyx as a genus distinct from Syzygium, together with Syzygium and Piliocalyx Brongn.& Gris, the last named genus occurring in New Caledonia, vanuatu and Fiji.Chantaranothai & Parnell (1994a, b) and Parnell (1999), in dealing with Thai species of the syzygioid group, recognised Acmena, Cleistocalyx and Syzygium (incl.Acmenosperma).For Malaya, Turner (1997) preferred to recognise Syzygium only (incl.Acmena, Acmeno sperma, Cleistocalyx).The issue was discussed by Craven (2001) who concluded that recognition of a single genus, i.e.Syzygium, was the only practicable solution in the light of present knowledge.
As a result of the work towards the accounts of the syzygioid genera for Flora of Australia mentioned above, four undescribed species were identified from north-eastern Queensland; these are newly described below and placed in Syzygium.Where relevant, notes are given on the placement of the species relative to genera accepted by other workers.
The reproductive seasonal growth unit that is described for each of the four species in this paper is defined as the shoot or flush of growth that includes the inflorescence.This growth unit may have a leafy zone in addition to the inflorescence per se or may consist entirely of the inflorescence.Craven,  Tree to 10 m tall, to 10 cm dbh.Bark nondescript.Branchlets compressed or quadrangular, winged, the wings not joined at the base, 0.5-1 mm diam.; bark dull, smooth or cracked.Leaf lamina elliptic, broadly elliptic or ovate, 3.5-8.5 by 1.3-3.4cm, 1.9-2.9times as long as wide, base cuneate or attenuate, apex long acuminate (tip of the acumen rounded or obtuse), acumen plane or recurved, margin revolute, entire, midrib rounded on the abaxial surface, primary and secondary venation generally similar with all or nearly all secondaries joining the intramarginal vein, primary veins 10-14 on each side of the midrib, divergence angle more or less uniform, in the median part of the lamina the veins at an angle of 55-70° and 1-3.5 mm apart, intramarginal vein present and 0.5-1.4mm from the margin, secondary intramarginal vein present (obscure and only visible after the removal of lamina surface tissues), oil dots visible to the unaided eye in transmitted light, the dots small, sparse.Petiole 2-4.5 by 0.6-0.8mm, axillary enations often present, 0.4-1.4mm long.Reproductive seasonal growth unit leafless.Inflorescence among the leaves, terminal, few-flowered and then cymose or spicate or 1-flowered, main axis straight and rigid, 0.5-1.6 by 1-2 cm, 0.5-1 mm thick at the mid point; bracteate, the bracts deciduous; bracteoles subtending each flower, or subtending the lateral flowers of a triad with the terminal flower ebracteolate, deciduous.Flowers not calyptrate.Hypanthium dull, obscurely gland dotted, stipitate, stipitately narrowly funnel-shaped or elongated-goblet-shaped, 5.5-7.5 by 2.5-4.5 mm, the stipe 1.5-2 mm long.Sepals 4, uniform in size or nearly so, transversely semicircular or transversely narrowly semi-elliptic, persistent, not accrescent, 0.1-0.5 mm long.Petals 4, deciduous, not coherent, 2 by 2-2.5 mm, margin entire or lacerate.Staminal disc unmodified or prominent.Stamens all fertile, outermost stamens 2-4 mm long; anther sacs parallel; anthers oblong, 0.3-0.5 mm long, dehiscing by longitudinal slits, connective not glandular.Style 4-6.5 mm long at anthesis.Placentation axile-median, the placenta weakly developed, narrowly oblong or sublinear (more or less flange-like).Ovules 4-6 per locule, pendulous, arranged in two longitudinal rows.Immature fruit smooth or glandular-verruculose, barrel-shaped, perhaps less than 12 by 7 mm at maturity, with the calyx rim not appreciably expanding in fruit, pericarp distinctly free from the seed and without peg-like intrusions into the seed.Seed 1, spheroidal, perhaps c. 4 mm diam.at maturity, testa absent, uni-embryonic; embryo with the cotyledons readily separable and with no interlocking placental tissue present, equal in size or nearly so.

syzygium fratris
Distribution -Australia (Queensland, Mt Bartle Frere, NW Peak).Habitat -rain forest; 1400-1500 m altitude.Notes -1.Flowers have been recorded in May and December.Fruits have been recorded in March.
2. The most closely related species to S. fratris may be S. canicortex B. Hyland.In both species the placentation is axile-median, the ovules are pendulous in two longitudinal rows in each locule, and the leaves are fairly similar in shape and size.However, the two species may be distinguished as follows: S. canicortex: flowers calyptrate (the calyptra is sepaline in origin and the petals adhere to and fall with the calyptra) and the fruit consequently lack sepals, leaves with axillary enations 0.2-0.5 mm long; S. fratris: flowers with 4 sepals and petals, the sepals persistent through to the mature fruit, leaves often with axillary enations, these 0.4-1.4mm long.
3. The epithet is derived from the Latin frater, brother, in reference to the locality Mt Bartle Frere which itself was named in honour of Henry Bartle Edward Frere, a former Governor of Bombay and a former president of the royal Geographical Society.Tree to 25 m tall, to 70 cm dbh.Bark reddish-brown-grey; flaky.Branchlets terete or rounded-compressed, 1.3-2.2mm diam.; bark dull, smooth or slightly striate.Leaf lamina narrowly elliptic, elliptic or narrowly ovate, 8.4-17.9 by 3.2-6.7 cm, 2.4-3.4 times as long as wide, base cuneate, obtuse or attenuate, apex acuminate (tip of acumen acute or occasionally rounded), acumen plane, margin revolute, entire, midrib angled or rounded on the abaxial surface, primary and secondary venation distinctly different with the secondaries relatively little developed and not joining the intramarginal vein, primary veins 19-42 on each side of the midrib, divergence angle more or less uniform or with the distal veins more acute than the proximal, in the median part of the lamina the veins at an angle of 55-70° and 3-11 mm apart, intramarginal vein present and 1.6-6 mm from the margin, secondary intramarginal vein present and a third is usually present, oil dots visible to the unaided eye in transmitted light, the dots small, sparse.Petiole 7.5-16 by 1.3-2 mm, stipules and/or axillary enations absent.Reproductive seasonal growth unit with distinct vegetative and reproductive zones or with a reproductive zone only.Inflorescence leafless, among the leaves, terminal or distal axillary, few-to many-flowered, paniculate, main axis straight and rigid, 3-40 by1.5-17 cm, 1-2 mm thick at the mid point; bracteate, the bracts deciduous; bracteoles subtending the lateral flowers of a triad but with the terminal flower ebracteolate, deciduous.Flowers calyptrate (the calyptra formed from fused sepals only, the petals cohere to the calyptra and fall with it), the calyptra 0.75-1.5 mm long.Hypanthium dull-glossy, not visibly gland dotted, stipitate, cup-shaped, 6-7 by 4.5-5.5 mm, the stipe 1.5-2 mm long.Petals 4, caducous, obsolete.Staminal disc unmodified.Stamens all fertile, outermost stamens 5-8 mm long, filaments inflexed in bud; anther sacs parallel, oblong; anthers 0.2-0.3 by 0.3-0.4mm, dehiscing by longitudinal slits, connective glands small, few.Style 5 mm long at anthesis.Placentation axile-apical, the placenta a small, anvil-shaped structure, lobing and compitum not seen.Ovules 3 or 4 per locule, pendulous, arranged radially in one row.Mature fruit rusty-brown, costate, obovoid (flattened at the distal end), 45-70 by 45-70 mm, with the calyx rim appreciably expanding in fruit, pericarp relatively dry (subwoody) and distinctly free from the seed, without peg-like intrusions into the seed.Seed 1, napiform, 35-53 mm diam., testa absent, with a mushroom-shaped structure that intrudes between the cotyledons and interlocks them, uni-embryonic; embryo with the cotyledons fully fused to each other or sometimes almost so (the epi-and hypocotyl at the outer edge of the embryo).
Distribution -Australia (Queensland, the Cape Tribulation-Daintree river region where it occurs in a single stand of relatively few mature trees).
Habitat -rain forest; c. 20 m altitude.Notes -1.Flowers have been recorded in March and May.Fruits have been recorded in February, June, August and November.
2. With calyptrate flowers, axile-apical placentation, pendulous ovules arranged radially in one row on each placenta, and the seeds having intrusive tissues between the fused cotyledons, S. glenum has many of the diagnostic features of Piliocalyx, a genus so far known only from New Caledonia, New Hebrides (vanuatu) and Fiji (Smith, 1985).The present species differs from Piliocalyx in having parallel anther sacs and unbranched intrusive tissue between the cotyledons, the sacs in Piliocalyx being divergent (Smith, 1985) and the intrusive tissue in the Piliocalyx seed being strongly ramified as in Syzygium smithii (Poir.)Nied.(Acmena smithii (Poir.)Merr.& Perry).If the narrow generic circumscriptions adopted for the Syzygium group of genera by some authors were applied to the present species, the combination of character states possessed by S. glenum would have resulted in it being classified in a monotypic genus.Considering the other Australian syzygioid species, however, the species has strong similarities to S. gustavioides (F.M. Bailey) B. Hyland in its foliage and the possession of a floral calyptra and parallel anther sacs.Syzygium gustavioides has anther sacs that are parallel to divergent, and the placentation, ovular arrangement, and seed/embryo characters typical of Syzygium s.s.Despite the considerable differences between the two species in the last three features, I consider that these two species are more closely related to each other than they are to any other so far known species.
3. The dry pericarp and its fibrous, subwoody texture prompts speculation as to how the fruits of S. glenum are dispersed.There is no aromatic or fleshy tissue that would induce a bird or mammal to eat the fruit.Also, the large size of the fruit would preclude ingestion of the fruit by all extant frugivores in the north-eastern Queensland rain forests with the exception of the Double-wattled cassowary, Casuarius casuarius.If indeed S. glenum has no extant dispersal agent, its very restricted distribution and very small population is more understandable given the apparent inedibility of its fruit.

syzygium monimioides
Tree to 20 m tall, sometimes a treelet, to 40 cm dbh.Bark red; flaky to scaly.Branchlets terete or compressed, rounded, 0.6-1.3mm diam.; bark dull, slightly striate or smooth.Leaf lamina ovate, narrowly ovate, elliptic or narrowly elliptic, 3.7-10.6by 1.2-4.3cm, 2-3.6 times as long as wide, base attenuate, cuneate or narrowly cuneate (occasionally approaching rounded), apex long acuminate or acuminate (tip of acumen acute, obtuse or rounded), acumen plane, margin revolute or flat (often appearing undulate but it is unknown if this is an artefact caused by drying), entire, midrib angled or rounded on the abaxial surface, primary and secondary venation distinctly different with the secondaries relatively little developed and not joining the intramarginal vein, primary veins 14-27 on each side of the midrib, the divergence angle more or less uniform or with the distal veins more acute than the proximal, in the median part of the lamina the veins at an angle of 55-65° and 1-5 mm apart, intramarginal vein present and 0.7-3.3mm from the margin, secondary intramarginal vein present, oil dots visible to the unaided eye in transmitted light, the dots small, dense.Petiole 3.5-9.7 by 0.5-1.2mm, axillary enations often present.Reproductive seasonal growth unit usually with a reproductive zone only (rarely with a pair of leaves subtending the proximal branches of the inflorescence).Inflorescence usually leafless, among the leaves, terminal or distal axillary, few-to many-flowered, paniculate, racemose or spicate, main axis straight and rigid, 1-6 by 0.5-2 cm, 0.4-0.6 mm thick at the mid point; bracteate, bracts usually deciduous (rarely a few persisting); bracteoles subtending the lateral flowers of a triad but with the terminal flower ebracteolate, or subtending the flower of a monad (monads apparently result from the abortion of lateral buds of triads), usually persisting or sometimes deciduous.Flowers cream, not calyptrate.Hypanthium dull, visibly gland dotted, stipitate, depressed-napiform, 3.1-3.8by1.3-2.3 mm, stipe 1.6-2.1 mm long.Sepals 5, papillate, 4 uniform in size or nearly so but with 1 sepal much larger than the others and almost petaloid, transversely narrowly oblong, transversely oblong or subcircular, 'petaloid' sepal subcircular, persistent, not accrescent, 0.2 -0.4 mm long.Petals 5 (sometimes imperfectly developed), papillate, deciduous, not coherent, 0.8-1.1 by 0.8-1.1 mm, the margin entire or lacerate.Staminal disc apparently slightly ascending (fully open flowers not seen).Stamens all fertile, outermost stamens c. 1 mm long, the filaments inflexed in bud; anther sacs parallel, transversely oblong or semisubcircular; anthers 0.2 by 0.3 mm, dehiscing by longitudinal slits; connective glands large, solitary.Style 2 mm long at anthesis.Placentation axile-apical, the placenta a peg-like protrusion from the apex of the locule into the locule.Ovules 2 or 3 per locule, pendulous, arranged radially in one row.Mature fruit apparently light green or green, glandular-verrucose, napiform, 10-12 by 11-15 mm, with the calyx rim not appreci-ably expanding in fruit, pericarp distinctly free from the seed and without peg-like intrusions into the seed.Seed 1, napiform, 10 mm diam., testa absent, uni-embryonic; embryo with the cotyledons readily separable and no interlocking placental tissue present, distinctly unequal in size.
Distribution -Australia (Queensland, East Normanby river-Mt Misery region).Habitat -rain forest; 150-600 m altitude.Notes -1.Flowers have been recorded in June, September and October.Fruits have been recorded in March.
2. This species has some floral similarities with S. wesa, e.g.acmenoid gestalt, papillae on the petals and sepals, reduced anthers (the anther sacs parallel in S. moni mioides and parallel or divergent in S. wesa).It differs from S. wesa in its axile-apical and peg-like placenta with 2 or 3 pendulous ovules per locule.Syzygium wesa has an axile-apical or axile-median, semi-obovoid or almost flange-like placenta with 6-8 pendulous ovules per locule.As far as the essential generic features are concerned, S. monimioides has two syzygioid character states (parallel anther sacs, seed without intrusive tissue between the two cotyledons) and 2 acmenoid states (axile-apical placenta, pendulous ovules).If one ascribes to the view that Piliocalyx, Waterhousea, Acmena, etc. are valid genera, then S. monimioides should be placed in a new genus.