DB. I. B. BALFOUB ON TEE QENUS PANDANUS. 33 Observations on the Genus Pandanus (Screw-Pines); with an Enumeration of all Species described or named in Books, Herbaria, and Nurserymen’s Catalogues ; togethGr with their Synonyms and Native Countries as far as these have been ascertained. By Dr. ISAACBAYLEY BALFOUB, F.L.S., F.B.S.E., &c. [Raad December 6, 1877.1 FEW families of plants present more diEculty in their elucidation than the Pandanacese. This arises from a threefold cause :-in the first place, from the variability of the species, dependent not only on relative position with reference to climatic influences, but also on the age of the individuals. Secondly, we find it is by no means easy to obtain characters sufficiently diagnostic, as the leaves afford marks of little or no value ; and hitherto it has been from the hit that distinctions have been drawn. The flowers of the male tree field in some instances good characters ; but we have as yet received flowers of only a few species, and these in some cases without information sufficient for identification with the female. Lastly, in dealing with primitive types of such varia- bilib, it is necessary to obtain a long series of specimens ere we can determine with certainty the limits of species ; and these, I regret to say, are still in great measure wanting. The di5- dty wgsrding specimens is still further increased by the fact that the fruib lose much of their character in drying. It is MepQfore +nost impossible to investigate the group without some q+nm of the planta in their native haunts, where, by a con- &&g&m of the combination of characters derived from habit, f&gq flower, and fruit, a correct estimate may be formed. Eaviag had opportunities of studying the group as repre- mnted in the Maacarene Iskds, and having already described * some species from these islands and from the Seychelles Islands, 1 have been tempted to enter on a large undertaking, and to contemplate a monograph of the whole Order. With this view I now venture to lay before the Bociety a synopsis of the species of the genus Panhnus, SO far as I have been able to determine them. I am quite conscious that, as it now stands, the list is a very imperfect one, and there are numerous errors. It c8n hardly be otherwise, founded, as it is, so greatly on inere descriptions usually very unsatisfactory. But I am advised to bring it forward in its present form, with the hope that any persons * Baker’s ‘ Flora of Mauritius and Seychelles,’ p. 395. W. JOUILN.-BOTANY, VOL. XVII. D 84 DB. I. B. BALFOUR ON THE GENUS PANDANUS. into whose hands it may fall, and who may be so situated as to have an opportunity of supplying information or material will not neglect it, and will thus forward the completion of the mono- graph. To render the list more serviceable, I have appended, in addition to the synonyms and references, all the popular names ; aud the locality is also given for each species. And, further, nt the end of the list will be found a short note with directions as to the most suitable modes of preserving specimens of the fruits of Pandanus. I do not intend at present to say any thing about the affinities of the Pandanaces, whether regarded as a familyper se, or as a tribe of a large group; but it may not be out of place to say a few words concerning the genus Prtndanm itself, as a prelndo to the list of species. Before the time of Linnsus the Screw-pines had attracted the attention of many voyagers and botanists ; and we find frequent references to them in the older works, but under designations and with descriptions which render it difficult to recognize them. The cnrliest reference to the plants I have seen is in ‘ Tractado de las Drogas ’ of Christopher Acosta, published in 1578. On page 347 of this book, we find n description of a species under the designa- tion Ananas Bravo; and there is a figure, very rude, but un- doubtedly intended to represent a Screw-pine. John Bauhin, in ‘ Historia Plantarum ’ p. 96, describes the same species, copying the figure, but alters the name to Ananas sykeskis, and gives as a synonym the Keura of the Arabians. We have references to the same plant, usually under the name of Ananas or Carduus, in the works of the various botaniets who wote towards the end of the seventeenth and commencemeut of the eighteenth century; and in 1’748 Linnaeus indicates the plant, in his ‘Flora Zeylanica,’ as Brornelia sylveetris. In the fourth volume of the ‘ Herbarium Amboinense,’ Rumphius in 1750 published an accouut,with figures, of thirteen kinds of Paidany or Pandanus Srom the Indian Ar- chipelago j and it is to him ne owe the mame of Pandanus. His descriptions are ercedingly bad, and the figures so poor-in striking contrast with those given by Reede in the second volume of the ‘ Yortus Malabaricus ’ nearly a century before-that any identi- fication therefrom is little more than a guess, though perhaps some light may be thrown on them by means of the local names, and a study of the species on the spot. In this state of confusion Linnseus omitted the genus from his system ; andit is only in the DE. I. B. BLLFOUB ON TIIE aENUS PANDINUS. 35 Supplemeut of the younger Linnaxs tlint we find the genuj Pal&- danus established as including oiic speciea, P. odoratissiriiics, but so briefly described that, were it not for the rcfercnces, \r-e should have some difficulty in iclentifying it. The genus so constituted iiicrensed in spccies, until nt present nearly sixty true species are known. IVitli tlie increase of species came attempts to break up the genus. Forstur aud ForskOal had, shortly after tlic publicntion of tlic younger Linnms’s Supplcmcnt, dcscribcd the species Iic indiciitecI undcr the generic names respccctivcly of di*throtkixtl/Zis am1 Iicui*n; mid these naturally enough uow fa11 into Pm~tZrcnzcs. Aii attempt was niade by Hassltarl to fouiid a new gems Xnryunrtitr, renamed Hasskarlia byWalpcrs,but on no sufficient ground. But it remained for Gaudichaud to carry the multiplication of geiiern to an cx- treme. In the Atlas of the Botany of thc ‘ Voyagc cle la Uonite,’ to which unfortunately no test was publishcd, arc figurcd fruits of various species of Pnizdnnus under 210 less tlisn thirtcen dif- ferent genera. Having seen in tlic Museum of Paris type speci- mens of nearly the whole of these, I have 110 liesilntiou in refer- ring them all to the one genus Pant7mus. In tliis way disappear the following genera-Barrotin, Uryantia, Dorystiginn, Zyilozcxia, EZ;Ppuetia,Fouillioya, He ferostigma, JIo iiih*oi2.ia,Jcaizneretirc, Rozcs- einia, Sussea, Tuckeya, and Vinsonia. 3hiy of Gaucliclinud’s species are identical with forms lriioirn before his time ; but tlicse are indicated B the list which follows, aud need not be further noticed here. Later De Vriese created two new genera, Doornin and Ryckin, which must share the fate of the others. Doornin includes a species which is said to be probably Nascarene, but idiicli 1do not how, unless it be Pandanus conglowzeratz~s,Balf. fil., though tho descrip- tion does not quite suit. The well-known Pnmlnizus fimatiis is the species on which Byckia was founded. Most recently, Brongniart, in working 111) the species of Pan- daneee from New Caledonia, has determined to keep 1111 the genera Barrotia and Bryantia of Gaudichaud ; and in tlicse he puts niany species from New Caledonia. I have seen his specilnens, and I do not consider there is any need for so doing. Indeed Brongniart rests his determination in great part on the structure of the male flowers, whilst, so far as the plates in tlic Atlas of the ‘ Voyage de la Bonite ’ and the specimens in the BTuscum at Paris go, there is uothing to show that Gaudichaud hewaught of the male flowers u2 36 DB. I. B. BALFOUB ON TEE GENUS PAADANUS. of the plants he put in these genera. Certainly the male flowers of Barrotia diodon, Gaud. (Panohus fwrcatus, Roxb.), do not correspond with the type described by Brongniart. Brongniart seems to have had some misgivings about putting his New-Cale- donian species under the genus Bryantia, and constitutes a sub- genus Lophostignta to include them. I have no doubt, then, that all those genera I have mentioned may be referred back again to the one genus Pandams, the de- finition of which, however, must be considerably altered from that commonly given. The genus contains, as I have said, a number of species which are distributed throughout the tropics of the Old World. Some few species, however, do extend beyond tropical boundaries. The genus runs through a great extent of longitude. A few species are found on the east coast of Africa; and thence it stretches eastward through the Mascarene Islands, India, and the Indian archipelago and Australia, until its eastern limit is reached about the Sandwich Islands. In fact, the species are found more or less between 30° N. and 30" 8. latitude, and 158" E. and 18O W. longitude. Throughout this range there seem to be two areas of distribution, one with its centre in the Mascarene Islands, and the other in the Eastern archipelago; and the species of each area do not commingle. It is worth while mentioning, as I have not seen it noticed elsewhere, that it is a common feature of the species of the Mascarene area to have red spines on their leaves, though this is not the case in all; whilst in the species from the Eastern area, so far as I know them, those with red spines on the leaves are the exception.