ALBERT

Description: The three species Galium silvaticum L., Galium aristatum L. and Galium schultesii Vest show differences in morphology, cytology and geographical distribution. These differences are described and discussed. Crossing experiments between the three species were without results. No hybrid could be obtained. Galium silvaticum, Galium aristatum and Galium schultesii must be considered as separate species.

Description: Merrill (Philip. J. Sc. 2, 1907, Bot. 284) based Mearnsia on specimens collected from Mount Halcon in the Phillipines and dedicated the genus to Major Mearns who accompanied him on the expedition. Merrill described the flowers of the sole species (M. halconensis) as 4-merous with 8 stamens and 2 carpels and the capsule as dehiscing by ‘a single slit at the apex only and inside the persistent calyx tube’.

Description: After the completion of my revision of Lepisanthes (Blumea 17, 1969, p. 33—91) I paid a visit to the herbaria at London (BM) and Kew (K). This led to a few alterations and additions, the main of which are the following.

Description: As explained in Takhtajan’s preface this book is not a mere translation of his ‘The origin of Angiospermous plants’ (1961, in Russian), but an entirely new book. I find this true and not true. Comparing it with the Origin (1958 translation of the 1954 Russian version) the essence of the new book was there given in a nutshell. In size, chapter subjects, argumentation, and bibliographic documentation, the work is very much extended and it makes very interesting reading indeed. The sequence of the chapters is logical, almost always leading to distinct synthesis. Properly it is a critical commented survey of many opinions — Takhtajan being clearly in complete command of the huge literature on the subject — but from which the author follows his own line of choice and judgement, accepting or rejecting with brief but clear comments. The whole argumentation is admirably concise and rouses admiration for covering this vast subject, comprising taxonomy, plant distribution, morphology, palynology, genetics, population dynamics, flower biology, anatomy, paleozoology, etc. Major questions are embodied in subsequent paragraphs: polyphyletism is rejected; ancestors must be sought among heterosporous ferns or fern-like plants followed by pteridosperms and certain gymnosperms, although direct ancestors cannot be indicated; the basal flower type of angiosperms was bisexual. Takhtajan attaches great importance to occurrence of plants in small populations, especially in mountain plants, facilitating chance variations and genetic drift, rapid spread of mutant genes, which is important for evolution. This entails that missing links are almost never fossilized. Micro-evolution is equalized with macro-evolution. Neoteny (on which Takhtajan devoted a former work) can lead to despecialisation through which phenotypic simplification the complexity of the genome remains intact; it may provide for a maximum phenotypic effect by a minimal genotypic change. Primitive wood structure of early Winteraceous angiosperms is understandable by neotenic origin. Evolution of angiosperms was not only rapid, but also discontinuous as a result of neoteny. Developing in the mountains ‘in many ..... small ..... populations ..... the earliest angiosperms found themselves under conditions most favourable to evolutionary radiation. And if we bear in mind that their evolution was closely tied to the evolution of insects and was based on the complex and peculiar mechanism of mutual selection, then the extraordinary speed of their initial differentiation becomes even more readily understandable.’ Protection of the ovules arose as a selection against damage by ‘early pollinating insects’; this made simplification of their structure possible which led to smaller ovules (loss of thickened integuments, sclerotesta, etc.) and enabled the angiosperms to observe the greatest economy of material in construction of the ovules and ♀ gametophyte, and it also made possible the perfection of the process of pollination. ‘The acquisition of the stigma was undoubtedly a very great event in the evolutionary history of seedplants.’ ‘The primitive insects searched for pollen (beetles), nectar searching ones were a further perfection; this again led to a very great advance in cross-pollination; and as a corollary to a greatly increased rate of evolution, which still continues.’ ‘Isolation of a population is well known to be a prelude to the formation of a new species.’ The question of the hypothetical reconstruction of the first flowering plants is approached by the ‘hypothetico-deductive method’. Knowing the basic evolutionary pathways of angiosperms and the main lines of specialisation of their organs and tissues, we may by extrapolation extend these lines mentally into the past to the lowest possible level of specialisation’, but somewhat further on he writes ‘This reconstruction of the ancestors of the living angiosperms depends on the truth of the assumption that they combined in one plant all the most archaic characters that are now found distributed among the living fossils.’ I have italicized in the citations two words that are in contradiction; furthermore I would like to point out that whereas each plant we know possesses both primitive and derived characters, we cannot make an exception for an ancestral plant; one which would contain all the archaic characters must logically be an idealized fiction.

Description: Rumphius (Herb. Amboin. 3, 1743, 19, t. 7) was the first to use the name Metrosideros, but of the 6 species he listed only the first, M. vera, belongs to the Myrtaceae. The same species is assumed to be the basis of Nani Adanson (Adanson, Families des Plantes 2, 1763, 88). Adanson did not list any species, but the assumption is based on the description and the fact that Rumphius had given the vernacular name of his Metrosideros vera as ‘Nani tree’.

Description: The pollen morphology of 18 out of 22 species of the genus Lepisanthes, as recently revised, was studied. General pollen morphology is rather uniform, but taxonomically significant differences exist in shape, relative length of ektoapertures, endoaperture development, and in the sculpture of the tectum. Detailed descriptions are presented and special attention is given to intraspecific variability. 10 Pollen types are recognized, most of which are linked by transitions. Morphological trends are established and the extent to which they indicate natural relationships is evaluated. In subgenera Lepisanthes and Erioglossum a less evolved but more variable pollen morphology is present, while in subgenera Otophora and Aphania derived pollen types occur, which agrees well with macromorphological evidence. Subgenus Erioglossum appears pollenmorphologically closely related to subgenus Lepisanthes. Subgenus Aphania can, both macro- and pollenmorphologically, be derived from subgenus Otophora. Within Lepisanthes tetraphylla close parallels exist between macromorphological and palynological interpretations of natural affinities between the numerous races. Lepisanthes fruticosa, in contrast, shows on both counts rather wide and continuous intraspecific variability. Also in Lepisanthes senegalensis continuous pollenmorphological variability is present, but here a clinal pattern can be detected. In general, geographically isolated or endemic forms in Lepisanthes show a tendency to develop deviating pollen types.

Description: Only two species of Gastonia occur in Malesia, but each has a complex taxonomie history. The species which became known first, G. papuana Miq., is evidently an uncommon plant of coastal and lowland forest, but with a very wide range. It has been collected only once, or at most a few times, from each of many islands of the Malayan Archipelago and once from the mainland of the Peninsula. Most of these collections were made in the nineteenth or early twentieth centuries. Only in western New Guinea has this species been collected in more recent times within our area. The distribution of this species shows several disjunctions, the most striking being that between West Irian and its only known locality in the extreme east of the Solomon Islands. It is interesting that this gap corresponds with the distributional range of the second species, G. spectabilis (Harms) Philipson, which overlaps that of G. papuana only in the west of New Guinea (fig. 1). The widely dispersed range of G. papuana has resulted in its being described as several distinct species from different parts of its range. It was first named in 1863, when three names appeared in two genera. Miquel (1863) applied the names Tetraplasandra paucidens and Gastonia papuana to this species, and Teysmann and Binnendijk (1863) described it as Tetraplasandra eupteronoides. I am grateful to Professor van Steenis for information on the sequence of publication of these names. Miquel’s publication was issued on 2 July 1863 (Stafleu, 1967). A report in volume 27 of the ‘Natuurkundig Tijdschrift voor Nederlandsch Indië’ states that volume 25 was issued in six instalments, the first of which appeared in 1862. The five remaining parts appeared in 1863. Professor van Steenis has examined the publication and concludes that page 416, on which the name T. eupteronoides appeared, belongs to the final instalment, and must therefore have been issued late in 1863, and in any event later than July. For this reason, Miquel’s names take precedence over that of Teysmann & Binnendijk. Of Miquel’s two names, I have chosen to use that which he placed in Gastonia. In this way the need for a new combination is avoided. As can be seen from its synonymy this species was described from other islands by subsequent authors.

Description: In continuation of a former study on the ‘Elevation Effect’ in the Swiss mountain flora (Backhuys, 1968), the distribution of six Taraxacum species in Switzerland was examined in detail. This was enabled by the preceding monographic study by J. L. van Soest (1969). The interesting point was to compare species of one genus with a common dispersal mechanism. Data on the vertical distribution are provided in table I and diagrams 1—6. It was found that all six species show an elevation effect which varies from 200—750 m. In five species this range is as narrow as 500—750 m. See table II. It is concluded that in spite of the very obvious dispersal mechanism (parachute-achenes) the species are apparently not capable to colonise ‘mountain islands’ the summit altitude of which is situated between the lowest known locality and the lowest mountain island on which the species concerned is found. These data support the view that the elevation effect is a plant-geographical rule of universal validity for mountain plants.