Rubus
Description
Shrubs (see under Morphology), usually climbing, straggling or creeping, rarely erect, only few species herbaceous.
Leaves compound (pinnately or palmately structured) or simple, then usually incised.
Stipules free, on the base of the petiole or at the junction of twig and petiole, persistent or fugacious, rarely absent.
Inflorescences terminal, elaborately branched with the lowermost branches often in the axils of the upper leaves, or little or not branched and in axillary bundles, or (rarely) strongly reduced and flowers (sub)solitary.
Flowers 5-merous, mostly bisexual, rarely unisexual and the plants ± dioecious.
Sepals imbricate, often unequal, outer margins often lobed.
Petals normally longer than sepals, rarely partly or entirely absent, white, less commonly cream-coloured, pink, purplish, or red.
Stamens many.
Fruits cohering and falling as a collective fruit with or without the torus, or (rarely) coming loose individually, drupes with usually a juicy or fleshy mesocarp and a hard and rugose endocarp.
Seed with thin testa.
Distribution
Asia-Tropical: Jawa (Jawa present); New Guinea present ‒ present; Philippines (Philippines present); Sumatera (Sumatera present), Subcosmopolitan present
Genus with some hundreds of species, apart from the microspecies in the apogamous R. fruticosusIR. caesius complex (according to Weber, Phan. Mon. 7, 1972, there are at least 5000 of those in Europe; see also under Taxonomy). Subcosmopolitan. In Malesia c. 50 species, New Guinea (17) and the Philippines (c. 17) being richest in species, followed by Java and Sumatra. In the area New Guinea is the only (small) centre of endemism with 12 endemic species, the other islands have very few endemics or none at all.
Ecology
Most species are light-loving and are restricted to more or less open places, either natural or anthropogenic. There does not seem to be evidence for suspecting apo-gamy in any of the Malesian species.
Morphology
European blackberry plants (R. fruticosus complex) usually make long vegetative shoots, called primocanes or turios, during the summer season. After their first winter a number of shorter mixed shoots appear in the leaf-axils of the primocanes. These mixed shoots, floricanes, are of determinate growth and terminate in an inflorescence. After fruiting, in autumn and winter, the floricanes die back and so does a larger or smaller part of the primocanes. New primocanes will, next spring, appear axillary on the lower nodes of still living parts of the old primocanes, from the subterranean parts, and from places where overhanging primocanes have rooted. These plants are not really shrubs, therefore. See Weber, l.c. (1972: fig.2).
Part of the tropical Rubus species may have the same kind of differentiation and periodicity in the branches but from herbarium specimens reconstruction is impossible. Field observations in the wild and in tropical botanic gardens are needed. In some cases it is obvious from the herbarium that there are two kinds of branches: long and stout ones with large leaves in whose axils shorter branches develop, terminating in an inflorescence. Continuation of growth of these shorter branches, if it occurs, must be sympodial.
Part of the tropical Rubus species may have the same kind of differentiation and periodicity in the branches but from herbarium specimens reconstruction is impossible. Field observations in the wild and in tropical botanic gardens are needed. In some cases it is obvious from the herbarium that there are two kinds of branches: long and stout ones with large leaves in whose axils shorter branches develop, terminating in an inflorescence. Continuation of growth of these shorter branches, if it occurs, must be sympodial.
Taxonomy
Focke (1910-11) recognized twelve subgenera but made clear in his text (p. 6) that he considered the smaller subgenera to be offshoots from the three larger ones, that represent the main subdivision of the genus: subgenus Malachobatus (centred in SE Asia), Idaeobatus (centred in E Asia), and Rubus (centred in S America). Nevertheless he put the large groups and the small offshoots on the same taxonomical level what from a phylogenetical point of view would not be the most acceptable classification. In the present survey also the subgenus Micranthobatus is recognized although it may not be a holophyletic group (see Kalkman, 1987). The subgenus Chamaebatus has been maintained with the same misgivings.
The genus Rubus has a bad reputation among taxonomists, undeserved since the problems are only caused by one Northern Hemisphere offshoot of the subgenus Rubus, the so-called 'MoriferV or R. fruticosus IR. caesius complex. The complex is taxonomically unsolvable, like others of its kind, because of the facultative apogamy and easy hybridization with stable progeny. It is possible to find the same 'taxa' year after year, to describe them, and to recognize differences with other, neighbouring 'taxa'. Over a large area, however, it is impossible to reach a hierarchic classification with more or less equivalent taxa. Although 'batologists' admit that their taxa are not comparable, they nevertheless try to classify them in the common scientific classification, and with predictably poor results. As one recent example, H.E. Weber () subdivides the subgenus Rubus in three sections (restricted to the NW European species). Of the three sections the Eufruticosi is the most important one, the two others accommodate, respectively, the dewberry (R. caesius) and the hybrids of the latter with Eufruticosi species. In the section Eufruticosi one of the two subsections contains the species that some authors consider to be hybrids with R. idaeus (belonging to subgenus Idaeobatus), the raspberry. The other subsection is divided into eleven series that are poorly recognizable and definable. As Weber himself says, in placing individual species in the series there is much room for the individual discretion of different authors.
The rest of the genus, however, behaves perfectly normally: there is a majority of well-recognizable, clear-cut species, several difficult cases of specific delimitation, and a small number of complexes like R. moluccanus that are obviously engaged in active speciation, possibly linked to an enlargement of their habitats by human interference.
The genus Rubus has a bad reputation among taxonomists, undeserved since the problems are only caused by one Northern Hemisphere offshoot of the subgenus Rubus, the so-called 'MoriferV or R. fruticosus IR. caesius complex. The complex is taxonomically unsolvable, like others of its kind, because of the facultative apogamy and easy hybridization with stable progeny. It is possible to find the same 'taxa' year after year, to describe them, and to recognize differences with other, neighbouring 'taxa'. Over a large area, however, it is impossible to reach a hierarchic classification with more or less equivalent taxa. Although 'batologists' admit that their taxa are not comparable, they nevertheless try to classify them in the common scientific classification, and with predictably poor results. As one recent example, H.E. Weber () subdivides the subgenus Rubus in three sections (restricted to the NW European species). Of the three sections the Eufruticosi is the most important one, the two others accommodate, respectively, the dewberry (R. caesius) and the hybrids of the latter with Eufruticosi species. In the section Eufruticosi one of the two subsections contains the species that some authors consider to be hybrids with R. idaeus (belonging to subgenus Idaeobatus), the raspberry. The other subsection is divided into eleven series that are poorly recognizable and definable. As Weber himself says, in placing individual species in the series there is much room for the individual discretion of different authors.
The rest of the genus, however, behaves perfectly normally: there is a majority of well-recognizable, clear-cut species, several difficult cases of specific delimitation, and a small number of complexes like R. moluccanus that are obviously engaged in active speciation, possibly linked to an enlargement of their habitats by human interference.
Uses
The plants contain tannins, which may be responsible for their use in cases of diarrhoea and throat-troubles. These uses are reported for tea made from leaves of the European Rubus fruticosus and also for R. moluccanus and some other Malesian species.
The fruits of all species are edible, but not all are as juicy and tasty as the well-known American and European blackberries (R. fruticosusI caesius complex), the raspberry (R. idaeus), loganberry (R. x loganobaccus), or Japanese wine-berry (R. phoenicolasius). The fruits of these and other species can be eaten raw as table-fruit or made into preserves, jams, jellies and fruit juices. A few Malesian species could be promising for these purposes, see .
The fruits of all species are edible, but not all are as juicy and tasty as the well-known American and European blackberries (R. fruticosusI caesius complex), the raspberry (R. idaeus), loganberry (R. x loganobaccus), or Japanese wine-berry (R. phoenicolasius). The fruits of these and other species can be eaten raw as table-fruit or made into preserves, jams, jellies and fruit juices. A few Malesian species could be promising for these purposes, see .