THONNER's analytical key to the families of flowering plants

For the identification of a flowering plant the first step usually is to discover to which family it belongs. With some experience, the families commonly encountered in one’s area of interest are soon known, but when dealing with specimens from other places, notably those from the vast and rich subtropics and tropics, there is much less certainty. The pertinent literature is often not readily available as it is often found only in expensive, rare or obscure books, or journals, present only in a few specialized institutes. Basically only a few keys to the families of flowering plants of the world have ever been produced, the best known of which at present is Hutchinson’s Key to the families of flowering plants (1973); less well-known are Lemée’s Tableau analytique des genres monocotylédones (1941) (incl. Gymnosperms) and his Tableau analytique des genres dicotylédones (1943), and Hansen and Rahn’s Determination of Angiosperm families by means of a punched-card system (Dansk Bot. Ark. 26, 1969, with additions and corrections in Bot. Tidsskr. 67, 1972, 152-153, and Ibid. 74 1979, 177-178). Of note also are Davies and Cullen’s The identification of flowering plant families, 2nd ed. (1979), which, however, deals only with the families native or cultivated in North Temperate regions, and Joly’s Chaves de identifição das famílias de plantas vasculares que ocorrem no Brasil, 3rd ed. (1977), which may be useful in other tropical areas too. There are a number of excellent keys prepared by an Austrian, Franz Thonner (1863-1928), which deal either with European genera (1901, 1903, 1918), or African ones (1908, 1913, 1915), or with all families of the world (1891, 1895, 1917). Some of these have apparently been completely overlooked, others have been known only to a few, and then sometimes served as a base for keys of their own, thereby again influencing keys by others (see Derived works)

A revision of the tribe Cephalantheae (Rubiaceae)

The tribe Cephalantheae is here reinstated; a full taxonomic treatment of all species is given, including a key to all species. The architecture and systematic relations are discussed

Tree Architecture, in Field and Herbarium

Tree architecture, the growth form of woody tropical plants, from lofty ’pagoda’ trees to low understorey pachycauls, has captured the imagination of professor and student alike. Previously many attempts had been made to study the growth form of limited plant groups,, but only recently has it been possible to see the wood from the trees as a result of the excellent work by Hallé & Oldeman (1970). This small book is crammed full with a wealth of information and profusely illustrated with clear schematic line drawings, supplemented here and there with photos of the habit of selected plants. The presentation, the clear style, and the excellent drawings offset any problems one might have with the language. The growth form is analysed into a number of architectural models all of which are illustrated. Numerous lists of examples of each model are given; from necessity the lists mainly contain African and South American species, but many families and genera also occur in Malesia. Recently Hallé has visited New Guinea and has published a short account of a selection of his observations (Hallé, 1974). It is regretted that more extensive lists of Malesian examples of each architectural model were not included in this paper. No new architectural models were found so one can, in principle, interpret the architecture of Malesian trees using the models discussed in his book

The identity of Quiducia Gagnep

Whilst working on the Rubiaceae for Flora Malesiana Prof, van Steenis brought to my attention the publication of Gagnepain of the genus Quiducia which seemed to occupy a most anomalous position in the tribe Psychotrieae. On examining the type material it soon became apparent that Quiducia represents a species of Silvianthus (Carlemanniaceae/ /Caprifoliaceae and is conspecific with the species described by Airy Shaw; the slight descrepancies between the two species as regards the placentation must be considered as faulty observation by Gagnepain

A synopsis of the African and Madagascan Rubiaceae — Naucleeae

The centre of distribution of the Naucleeae is Malesia and Asia, there are but a few African and Madagascan representatives. The revision of the group for Flora Malesiana entailed an extensive nomenclatural evaluation and typification of the genera (Bakhuizen van den Brink Jr., 1970). This has been followed by detailed taxonomic investigations and a re-evaluation of the tribal and generic limits. The Naucleeae, as conceived by K. Schumann (1891), have mostly been considered a highly natural group (Verdcourt, 1958) and have even been raised to family status (Airy Shaw, 1973). Bremekamp (1966) has been the only botanist ever to question the homogeneous nature of the Naucleeae. However, after re-examination of materials of most representatives of all genera and sections of genera one could only come to a conclusion similar to Bremekamp’s. The only character that die genera of the tribe have in common is the arrangement of the inflorescence in a spherical head, a feature recurring independently in many tribes. The genera Mitragyna and Uncaria are here placed together in a subtribe Mitragyninae and transferred to the tribe Cinchoneae; Cephalanthus is transferred into a separate tribe, a move first suggested by Bremekamp (1966). These groups will be treated separately in papers shortly to appear. The remaining genera, as far as can be judged, form a somewhat homogeneous tribe

Notes on New Guinea Rubiaceae. Versteegia and Maschalodesme

Within the rain forests of New Guinea there are many small pachycaul treelets belonging to the Rubiaceae. Generally these are rare in occurrence and poorly represented in the herbarium, due in part to the problem of protecting rami- or cauliflorous flowers and fruits during routine processing and storage. All have a similar general appearance and are difficult to assign to a particular genus. Indeed, the generic limits and relationships of many have been in doubt since they were described and few have been re-investigated in light of more recent collections and ideas. Versteegia and Maschalodesme are two of the better known genera. These are considered from a taxonomic point of view together with notes on the wood anatomy and cuticular structures. The other genera are less well known and include Airosperma in the Alberteae and many problematic species and genera in the Psychotrieae. These are distinct from both Maschalodesme and Versteegia and are not considered in the present paper