On the delimitationbetween Aristotelia l’Hér. and Sericolea Schltr. (Elaeocarpaceae) M.M.J. van Balgooy Rijksherbarium, Leyden INTRODUCTION between Dr Steenis and Mr C. T. The present investigation arose from a discussion van White from North collected in July 1950 concerning a plant Queensland, by Mr L. J. Aristotelia but also showed Brass. The specimen was pre-identified as an similarity with the the Papuan genus Sericolea. The need was felt to investigate the distinction between two genera. Mr White was very keen to investigate the problem himself but this was this unfortunately prevented by his untimely death, only two weeks after discussion. The has problem rested ever since, until in 1963 I had to verify the distinction between for work the Pacific work executed under from the two genera my on flora, a a grant the Netherlands Organisation for the Advancement of Pure Research (Z.W.O.). became it examine Aceratium I soon aware that was inevitable to the closely allied genera has also made and Vallea as well: A comparison with other Elaeocarpaceae been where it seemed appropriate. A review is given of the value and constancy of the characters. Diagnostic descriptions of Aristotelia and Sericolea are here presented and a key for the distinction of the opposite-leaved Elaeocarpaceae. Finally the plant-geographical impor- tance of the family is briefly discussed. Thanks are due to the directors of the following herbaria for the loan of material: Brisbane (BRI), Kew (K), Melbourne (MEL), and Utrecht (U); to Dr van Steenis for criticism in and help preparing this paper, and to Dr Leenhouts for advice. HISTORY AND NOMENCLATURE OF ARISTOTELIA AND SERICOLEA first Mai. Aristotelia was described by L'Heritier from Chile in 1786 (not 1784; fide Fl. later described from I, 4, 1954, cxcvii) as a monotypic genus. Some species were New such Zealand, Tasmania, and New South Wales, sometimes under other generic names, the Friesia DC. On the other from as synonymous hand, Queensland, New Guinea, and Aristotelia of the New Hebrides species were described under which in the course all timehave been transferred to other genera. Sericolea was founded by Schlechter in 1916 to accomodate 6 New Guinea species, including Aristotelia gaultheria F. v. M. In the same paper he reduced Aristotelia braith- waitei F. v. M. to Aceratium DC. that Aristotelia It is not surprising F. v. Mueller had accomodated these species in in of the close mentioned. view relationships which exist between the three genera just Especially as regards the Papuan plant, Von Mueller himself was not quite convinced that Aristotelia was the correct generic disposition. Various authors have subsequently added to the number of Sericolea species, all from of and New Guinea; many these were originally described under a wrong genus family: Hormopetalum Lauterb. 1918 (Rut.); Mischopleura Wernh. 1916 (Eric.); Pyrsonota Rial. 1916 ( Saxifr.). BLUMEA VOL. XII, No. i, 1963 80 A short nomenclatural note must be added concerning Hormopetalum and Mischo- pleura. Lauterbach (Bot. Jahrb. 55, 1918, 257) published Hormopetalum as a new genus follow belonging to the Rutaceae with reference to a fuller description to in Nova Guinea volume 12. In the meantime he provided a key to three species (in German), a Latin of and a German). A later description one species, added generic diagnosis (in year for Schlechter pointed out that Hormopetalum was congeneric with Sericolea, which Schmidt reason Lauterbach's publication in Nova Guinea was obviously suppressed. O. C. the which not (1924, 152) considered Hormopetalum a nomen as well as two species were provided with a full Latin description. This is nomenclaturally erroneous, as was already pointed out by A. C. Smith (1944, 104). first in Hooker's Icones Mischopleura was published in a paper by Ridley 31 (June of Ericaceae. The from 1916) t. 3059 as a new genus description was obviously copied and the fact that Wernham Wernham by reference to a then unpublished account, by and Wernham's of was cited as the author of genus species. description Mischopleura Therefore, the correct appeared two months later in Trans. Linn. Soc. Bot. 9 (1916) 99. Wernham citation is: Mischopleura in Ridley, Hook. lc. 31 (1916) t. 3059. DISCUSSION AND EVALUATION OF CHARACTERS General habit between Both shrubs There is little difference in habit Aristotelia and Sericolea. are or small a of metres. Sericoleas sometimes reported as trees, rarely attaining height 10 are epiphytes but this is nothing special for undergrowth components of the dense everwet and forest and crests.Prostrate and ericaceous growth- montane rain-forest mossy onridges forms of both occur in species genera. Phvllotaxy in the in Together with Aceratium, Sericolea and Aristotelia are unique family having leaves. found in besides the ordi- normally opposite Occasionally specimens are which, of leaves in whorls of three. In a few species nary condition, some are subopposite or Elaeocarpus, Sloanea, and Tricuspidaria (Crinodendron) opposite, subopposite, and spiral be found and the leafarrangement may occasionally on one same plant. Leaves Sericolea differ number of The leaves of Aristotelia and in a points. herbaceous leaves. The only Aristotelia has as a rule long-petioled, or submembranous has less coriaceous leaves. exception is A. fruticosa Hook. f. which short-petioled, more or coriaceous Sericolea has always short-petioled to subsessile leaves, which are either stiffly but in or thin firmly pergamentaceous texture. The lamina in Aristotelia is ovate to lanceolate and, A. fruticosa excepted, much larger than Sericolea. the latter the leaves are generally smaller and are either oblong- in In genus and obtuse. The venation ovate with a long-acuminate driptip or more rarely elliptic is also of diagnostic value. Aristotelia is widely nerved, the lateral nerves looped and thelowermost of and thicker than the others, the lamina joined; as pair nerves is opposite to the is subtriplinerved. Sericolea is densely nerved, the lateral nerves running straight foundotherwise margin. Within the family this nervationpattern is almost unique, being only in Aceratium sericoleopsis v. Balgooy from Queensland. denticulate to serrate, entire. In both genera the leafmargins are very rarely of In leaf characters Aristotelia comes close to Vallea and to certain species Aceratium. M. M. J. VAN BALGOOY: On the delimitation between Aristotelia and Sericolea 81 Indumentum covered have All species of Sericolea are with sericeous hairs, which a silvery or golden shine. be the older but Some species may nearly glabrous, especially on parts, some appressed hairs are always present, at least on the yong parts, on the midrib on the under- side ofthe leaf, and on the inflorescence. Aristotelia of is patently soft-pubescent; besides, the species this genus are generally of with that of Vallea. more glabrous. The indumentum Aristotelia agrees also Sericeous hairs are found in some species of Elaeocarpus and Aceratium. Especially some of the Australian species of Aceratium show a deceptive resemblance to Sericolea in sterile the state as pointed out in another paper (v. Balgooy 1963, 71). In general, much however, Aceratium is densely tomentose or even hispidulous, the hairs being and of reddish colour. coarser mostly a rusty or Stipules the should be in both Though, according to literature, stipules wanting genera, I found small filiform caducous This character to be occasionally stipules. appears taxo- nomically unimportant in Elaeocarpaceae, as, for instance in Vallea, large reniform stipules may be present or wanting on the same plant. Inflorescence The and of inflorescence is in both genera axillary consists in most species a cyme, of few decussate flowers. In the flowers raceme, or thyrse some species may be solitary and in A. serrata (Forst.) Ohv. they form a compound many-flowered panicle. Flowers In both genera the flowers are 4—5-merous and generally hermaphrodite. Only the two in dioecious. the New Zealandic Aristotelia species are aberrant being In a plants of the androecium the the also these only is developed, whereas in $ plants stamens but flowers the develop to various degrees, are apparently non-functional; in $ petals are often reduced in size. Calyx The valvate and outside. Inside sepals are ovate, acute to obtuse, hairy they are always in Sericolea. latter glabrous Aristotelia, minutely puberulous in most species of In the genus have less median they moreover a more or distinct, longitudinal, ridge inside. Corolla The aestivation of the petals is induplicate-valvate in Sericolea and slightly cochleate Aristotelia in (not quincuncial as stated by Szyszylowicz, 1885, 447). In shape they vary from broadly to narrowly obovate, and from nearly entire to deeply three-lobed. In most species of Aristotelia (the only exception being A. fruticosa Hook. f. from New Zealand) the petals are thinner than in Sericolea where they are more or less fleshy. In Sericolea hairs inside the base of there is in most species a patch of at ofeach petal. The structure the corolla again links Aristotelia with Vallea, whereas the corolla type of Sericolea is otherwise only found in Elaeocarpus bilobatus Schltr. Aceratium has a distinctly different corolla; here the petals are much larger, often fimbriate or deeply lobed, and densely hairy at the base and the The that ins'de along margin. marginal hairs are interwoven so the petals remain often firmly coherent in the lower half. 81 82 BLUMEA No. VOL. XII, i, 1963 Disk As in all of the disk is genera Elaeocarpaceae a present. Its structure and place offer good characters between Sericolea and Also ofthe diagnostic Aristotelia. in other genera family Sericolea with they are important for generic distinction. In it is an extrastaminal ring thick episepalous lobes before which the stamens are inserted. Sometimes some smaller lobes between additional disk are developed the larger ones. This type of disk is also found in but in whereas some Elaeocarpus species that genus the disk is puberulous, in Sericolea it is always glabrous.