Portulacaceae
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Portulaca in Indo-Australia An account of the genus and the Pacific (Portulacaceae) R. Geesink Summary historical is ofthe earlier treatment ofthe genus. Inthe introduction a brief review given moreimportant In observations, I have also inserted remarks on the systematic value chapter 2, covering morphological hairs have often been ofcertain features. The axillary (and in sect. Neossia, nodal) interpreted as representing order to show that their stipular homology is most stipules. I have tried to advance arguments in unlikely. essential difference between the of the in- It is confirmed that there is no morphological structure florescence and that ofthe vegetative portion of the plant. about the of the 2-whorled the series There is no unanimity of opinion interpretation perianth; outer refers the whorl is to be of bracteal nature. Von Poellnitz to outer as ‘Involukralblätter’, often accepted a the fact that in with flowers in Legrand names them ‘pseudosepalos’. However, subg. Portulaca, capituli, the which is adnate to the basal ofthe the whorls are inserted at the same height on receptacle part ovary, make there two true bracts, it almost certain and the fact that below the receptacle are generally that such with flower and ‘bracteoles’. This is assemblage is a contracted triad, one developed 2 cymose nature further sustained by the species of subg. Portulacella in which true cymes occur. In it the wide distribution of several species, P. P. chapter 3 is argued that present e.g. pilosa, quadrifida, and P. oleracea, is mainly due to man, by his transport and cultivation. Such species behave often as ruderals Of some of these the native is for these and adventives beyond their original country. genuine country P. reasons even unknown or very uncertain, e.g. that of the diploid oleracea; its cultivated strain is hexaploid found ruderal and adventive. s. l. be ofAustralian but this is also as a P.pilosa may originally origin,judging its from the geographicalarea of nearest allies and the very large degree of variability it exhibits in Australia. in ofthe Self-pollination is obviously the rule in Portulaca as well as Talinum, another genus same family; this may even be prevalent in the entire family. This implies, and explains, a profuse occurrence of more or nature constantin details (e.g. the or less pure lines (local populations races) in which keep sculpture former ofthe testa). For this reason, not a few ofthese have been distinguishedas (micro) species by authors. field the herbarium. have Some of these characters are more conspicuous in the than in For example, I of such lines of Talinum which their differ grown two paniculatum throughout range (in living state) constantly in the following three minor characters: testa minutely tubercled or smooth, panicles narrowed or not, fruits red or yellowish. Such characters would seem to be determined merely by a few genes, formal and do not or hardly deserve systematical recognition as taxa. They are just on the border of work. herbarium taxonomy, and can only be solved, as to their genetical basis, by experimental taxonomie in in Only when more and clearer characters occur combined complexes I have accepted these a formal P. On I in taxonomie hierarchy, e.g. in pilosa. the whole have felt induced to be rather conservative accepting but reduced to to rank. good species, many are synonymy or infraspecific In It chapter 4 the subdivision of the genus is discussed. appeared that those of von Poellnitz (1934) and I (to a lesser degree) Legrand (1953, 1958) are unsatisfactory. have framed a new, more simplified, sub- division reflecting my ideas. Some taxa could not well be understood and have been referred to under the genus. From the and it is concluded that the ancestral ofthe is in morphology taxonomy lineage genus Australia, which fitsin with of is the general geographicalconfiguration the family which predominantly a southern hemisphere group. Chapter which been effected as 5 contains some notes ontypification, has as much possible, mainly by be untraceable. lectotypification. Unfortunately, some types proved to The covered area in this account ranges from India eastwards throughIndo-Australia as far as the Central I Pacific. have refrained from citing specimens examined. A list of these will be published separately as an Identification List. In the systematic treatment full synonymy, descriptions, and keys are given to taxa, both species and 276 BLUMEA VOL. XVII, No. 2, 1969 absence of lack of infraspecific entities. Not all names could be placed, either by types or material. These listed at the tentative to their are end; suggestions are given proper identity. The number of species distinguished in Portulaca has varied enormously. Linnaeus had only 2 species, P. P. Kewensis In in oleracea and pilosa; Index lists c. 600 names. this century von Poellnitz has described described dozens of his papers precursory to his monograph many new species. For a large part he withdrew of these again and sunk them into synonymy in his monograph 1934, in which he accepted in all 104 species. authors. in his revision American Subsequentlyc. 30 new species were added by various Legrand (1962) ofthe species reduced quite a number of von Poellnitz’s species, still maintaining 62 species for the New World. of He distinguished, however, a large number of varieties reflecting the variability these species. More P. than 50 of his species belong to subsect. Stellulato-tuberculatae,mainly comprising the pilosa complex. In I 8 my opinion this complex consists of only one compound species, in which have distinguished sub- species for Indo-Australia. In America P. pilosa is obviously still more variable. I estimate entire consists that the genus of not more than 15 good species, mainly in the Old World, viz. in in subg. Portulacella, 3(—5) subg. Portulaca sect.Neossia, 2(—7) in sect. Portulaca subsect. Portulaca, 4—5 , and possibly only 2 in sect. Portulaca subsect. Stellulato-tuberculatae. The Linnean and in that the two species, P. pilosa P. oleracea, possess, sequence, greatest variability. The generic name Meridiana Schrank is reduced to Trianthema L. 1. Introduction revision revision of Portulacaceae This was intended primarily as a precursor to the the the for Flora Malesiana. During the course of the work it appeared, however, that I had and because to spread my wings wider wider of synonymy and confusion by frequent of involved for the frame of the misinterpretation names. It also, infrageneric taxa, examining species of all subgenera and sections. of viz. oleracea and Linnaeus recognized in 1753 only 2 species proper Portulaca, P. their number had increased Poellnitz's of and P. pilosa; to 104 in von monograph 1934, that have been described. and Mueller since time some 30 more Engelmann (1850) von subdivisions Schlecbtendal excellent (1859) gave the first of the genus. Von (1853) gave an that he had in critical survey of the species then known; his advantage was many species cultivation. Poellnitz's work 'Versuch der Portulaca' In von main einer Monographic Gattung and (1934) many provisional names were legitimized many provisional descriptions were extended; the compilation itself is composed of rather brief but uniform descriptions. This work was preceded by several smaller papers, and also later small supplementary him. find his work critical. papers were published by I not very for Legrand (1962) made a revision of the American species which proved helpful some he subdivisions of identifications. In two other papers (1953, 1958) proposed new Portu- he did attend to and nomenclature. laca; unfoitunately not sufficiently proper typification I have made the typifications of his infrageneric taxa as well as I could, but must admit of it should that my knowledge these, mostly American, species was not as profound as have been for this purpose. One of the difficulties in Portulaca is that herbarium material is often badly preserved if it has been dried too slowly. The best way is drying after having killed it in alcohol or boiling water. The corolla is often difficult to discern as it is marcescent. To I P. oleracea study the morphology properly had at my disposal living material of and P. pilosa ssp. pilosa. Furthermore I cultivated two species of Talinum. 2. MORPHOLOGICAL AND SYSTEMATIC NOTES I. Habit. — Perennial, mostly copiously branched, not rarely prostrate, frequently either rooting at the nodes. Most species are succelent to various degree, in leaves or stem or in both, but P. wightiana is distinctly xeromorphic (fig. 4). R. Geesink: Portulaca in Indo-Australia and the Pacific 277 this Both the main root and its main branches are generally tuber-like swollen; seems but rather be observed the herbarium because to be a general tendency, can rarely in collectors mostly neglect to collect the subterranean parts. is Except for the species ofsubg. Portulacella, which are glabrous (only P. digyna entirely covered with all Portulacas white pale hairs in the axils of the leaves papillae), possess or in extending sometimes on the node. Sometimes these hairs are inconspicuous (as P. the internodes oleracea), but more frequently they are conspicuous; especially if are short, they may give the stem a hairy appearance. Portulacella and Portulaca 2. Leaves. — The leaves are opposite in subg. in subg. sect. the of the Neossia, and spirally arranged in rest genus, though occasionally subopposite the linear to lan- leaves can be observed in P. oleracea and P. lutea. In P. pilosa leaves are and other lanceolate to orbicular and flat. In ceolate mostly terete; in species they are scales of the leaves are small and hidden the scarious P. wightiana the very by axillary with the and nodal hairs in other next-lower node; these scales are homologous axillary species; the leaves are caducous.