New or noteworthy species of Leguminosae in NE tropical Africa

The following new species are described: Chamaecrista dunensis (Somalia), Acacia densispina (Somalia), A. flagellaris (Somalia), Tephrosia karkarensis (Somalia), T. scopulata (Somalia), Indigofera ancistrocarpa (Kenya), I. curvirostrata (Ethiopia), I. hiranensis (Somalia), I. karinensis (Somalia), I. kucharii (Somalia), I. nugalensis (Somalia), I. pellucida (Kenya, Somalia), I. sabulosa (Ethiopia, Somalia), I. sessilis (Somalia), I. ienuirostris (Somalia), Rhynchosia megalocalyx (Somalia), Crotalaria allophylla (Somalia), C. intricata (Somalia), C. warfae (Somalia), and Coronilla somalensis (Somalia). 2n = 22 is reported in Tephrosia karkarensis. Cassia somalensis, Acacia puccioniana, Sophora somalensis , and Crotalaria sennii are reduced to synonyms of respectively Senna hookeriana, Dichrostachys kirkii, Millettia usaramensis and Crotalaria boranica subsp. trichocarpa . Thirty-seven taxa are reported from Somalia for the first time, including Ptycholobium biflorum , known previously only from Southern Africa. Crotalaria pieropoda , known previously only from Socotra, is reported from Somalia and Oman. Neptunia oleracea and Vatovaea pseudolablab are new generic records for respectively Ethiopia and Oman. The fruits of Indigofera boranica are described. Vigna somaliensis and an allied species are discussed. Rhynchosia gansole is lectotypified and its flowers and fruits are described.     

Eight new species and a new record of Indigofera and Microcharis (Leguminosae-Indigofereae) from Somalia

The following new species are described: Indigofera bayensis (south-west Somalia, on sand or gravel in Acacia-Commiphora bushland), I. gypsacea (central and south-west Somalia, on gypsum), I. karkarensis (north-east Somalia, on limestone), I. lamellata (south-west Somalia, on and around granitic outcrops), I. lughensis (south-west Somalia, on gypsum), I. phymatodea (south-west Somalia, on granitic outcrops), I. scopiformis (central Somalia, on sand in Acacia-Commiphora bushland), and Microcharis nematophylla (central Somalia, on sand in Acacia-Commiphora bushland). Indigofera pseudointricata , previously known only from Socotra, is reported also from Somalia.     

Section of tropical taxonomy: Seven new species and one new record of Polygala (Polygalaceae) from Somalia

The following new species are described: Polygala gypsophila (northern, central and southern Somalia, on gypsum), P. bariensis (northern Somalia, on limestone), P. hamarensis (coastal dunes near Mogadishu), P. argentea (central Somalia, on limestone near coast), P. gawenensis (central Somalia, on limestone), P. effusa (central Somalia and eastern Ethiopia, on sand), P. citrina (southern Somalia, on granitic outcrops). P. meonantha is reported for the first time from Somalia.     

Ten new species of Commiphora (Burseraceae) from Somalia

The following new species are described: Commiphora arenaria from bushland on sand in south-central Somalia, C. gardoensis from limestone slopes in the Qardho area in north-eastem Somalia, C. stellatopubescens from bushland on limestone outcrops or stony ground in the Hiiraan Region in south-central Somalia, C. spinulosa from limestone rocks on the escarpment along the Gulf of Aden in northeastern Somalia, C. lobatospathulata from bushland on sand in central and south-central Somalia, C. quercifoliola from bushland on shallow soil over limestone near Eil in north-eastem Somalia, C. chiovendana from bushland in northern and central Somalia, C. multifoliolata from limestone hills and ridges in south-westem Somalia, C. murraywatsonii from limestone outcrops near Hobyo in central Somalia, and C. kucharii from bushland on shallow soils over limestone in central and southern Somalia.     

Seven new species of Pavonia (Malvaceae) from the Horn of Africa

Pavonia friisii , sp. nov., from south-eastern Ethiopia and south-central and southern Somalia, P. nigrescens , sp. nov., from south-central and southern Somalia, P. matteiana , sp. nov., from south-central Somalia, P. longipilosa , sp. nov., from eastern Ethiopia, P. rotundifolia , sp. nov., from eastern Ethiopia and northern and central Somalia, P. marginata , sp. nov., from central Somalia, and P. paucibracteata , sp. nov., from central Somalia, are described and illustrated.     

Four new species of Commicarpus (Nyctaginaceae) from NE tropical Africa

The new species Commicarpus hiranensis from the inland of central Somalia, C. mistus from Somalia, SE Ethiopia, NE Kenya and S Arabia, C. parviflorus from the coastal and subcoastal parts of central Somalia, and C. ramosissimus from NE Somalia are described and illustrated.     

Four new species of Sida (Malvaceae) from the Horn of Africa

Sida floccosa , sp. nov., from eastern Ethiopia and north-western Somalia, S. ogadensis , sp. nov., from eastern Ethiopia and central Somalia, 5. calliantha , sp. nov., from coastal dunes in southern Somalia, and S. longipedicellata sp. nov., from coastal dunes and sandy plains in central and south-central Somalia, are described and illustrated.     

Molecular evolution and phylogenetic implications of internal transcribed spacer sequences of nuclear ribosomal DNA in the Phaseolus-Vigna complex.

Molecular phylogeny based on internal transcribed spacer (ITS) sequences was studied to resolve the taxonomic contradiction in Vigna and its relation to Phaseolus. The ITS region of the 18S-26S nuclear ribosomal DNA repeat was sequenced for 29 Vigna species, selected from five of the nine subgenera, and 9 species of Phaseolus. The length of ITS-1 ranged from 187 to 243 bp and 217 to 290 bp, and that of ITS-2 from 187 to 219 bp and 225 to 243 bp, within Vigna and Phaseolus species, respectively. Phylogenies derived from ITS sequences based on maximum-parsimony and neighbor-joining methods gave trees essentially of similar topology. The ITS phylogeny was generally congruent with recent classifications based largely on morphological, biochemical, cytogenetical, and palynological features, except that subgenus Plectotropis of Neotropical origin was revealed to be closely related to subgenus Vigna instead of forming a link between African (subgenus Vigna) and Asiatic (subgenus Ceratotropis) vignas, and subgenus Sigmoidotropis, featuring morphological characters of both Vigna and Phaseolus, was placed as the sister group to the Phaseolus taxa. The ITS sequences were shown to be useful for identifying wild progenitors of V. mungo, V. radiata, V. umbellata, and V. unguiculata and for clarifying taxonomy-related problems in many previously controversial cases. This study also affirms that V. umbellata and V. angularis are the diploid progenitors of the only tetraploid species (V. glabrescens) known in the genus.     

Three new species of Chascanum (Verbenaceae) and notes on the genus in the Horn of Africa region

The new species Chascanum mixtum, from evergreen bushland and rocky slopes in north-western Somalia, C. elburense. from deciduous bushland mainly on sand in central Somalia, and C. glandulosum, from Acacia-Commiphora bushland on sandy soil in north-western Somalia, are described and illustrated. C. sessilifolium (Vatke) Moldenke is recircumscribed and neotypified with a specimen from the original type locality, and C. obovatum Sebsebe ssp. glaucum Sebsebe is placed in the synonymy of C. gillettli Moldenke.     

Notes on Convolvulus, Astripomoea, Ipomoea and Merremia (Convolvulaceae) from the Horn of Africa

The six new species Convolvulus scopulatus, a shrub from gypseous semidesert coastal plains in northern Somalia, Astripomoea procera, a woody climber in Acacia-Commiphora bushland on sand in south-central Somalia, Ipomoea hiranensis, a prostrate or climbing shrublet in Acacia-Commiphora bushland in rocky places on sandstone in south-central Somalia, Ipomoea galhareriana, a woody climber in bushland on sand in central Somalia, Ipomoea pogonantha, a woody climber in bushland usually on red soil over limestone in eastern and southern Ethiopia, southern Somalia and northern Kenya, and Ipomoea corrugata, a herb with trailing stems in bushland on sandy soil in south-central Somalia, are described, and illustrations are provided for most of them. The new combinations Ipomoea ovatolanceolata (= I. adenoides var. ovatolanceolata) and Merremia obtusa (= M. ampelophylla subsp. obtusa) are made, and a new synonymy is provided for M. ampelophylla. Merremia ellenbeckii is neotypified and M. lobata is placed in synonymy.     

Bauhinia leucantha sp. nov. (Leguminosae-Caesalpinioideae) and notes on B. ellenbeckii

Bauhinia leucantha sp. nov. is described from central Somalia. The new species is related particularly to B. ellenbeckii in Ethiopia and Somalia, B. teitensis in Kenya, and B. natalensis in eastern South Africa. B. somalensis is reduced to a synonym of B. ellenbeckii and the distribution of this species is shown to extend to northern Somalia.     

Genetic diversity and phylogenetic relationships in Vigna Savi germplasm revealed by DNA amplification fingerprinting.

The pantropical genus Vigna (Leguminosae) comprises 7 cultivated species that are adapted to a wide range of extreme agroclimatic conditions. Few data are available on the relationships among these cultivated species or on their importance as sources of resistance against biotic and abiotic stresses. Therefore, we optimized DNA amplification fingerprinting (DAF) to estimate the genetic diversity within, and genetic relationships among, a representative core collection of cowpea, as compared with 16 accessions representing cultivars from 6 Vigna species. A set of 26 primers was selected from 262 tested random primers and used for the characterization of 85 Vigna accessions (6 V. angularis, 4 each of V. mungo and V. radiata, 2 V. umbellata, 1 V. aconitifolia, and 68 V. unguiculata), with Phaseolus vulgaris subsp. vulgaris as outgroup. A total of 212 polymorphic bands were used for maximum parsimony analysis. Our results clearly distinguished Brazilian from African V. unguiculata genotypes. At the species level, V. angularis was the most related and V. radiata the most divergent species relative to V. unguiculata. DAF markers were also informative at the intraspecific level, detecting a large diversity between cowpea cultivars. The implications of the presented results for cowpea breeding programs are discussed.     

杜鹃花属植物的可育性研究进展

结合作者近年来的工作, 总结了国内外有关杜鹃花属(Rhododendron)植物可育性研究的成果和进展, 旨在为相关研究者和技术人员提供参考。(1)杜鹃花属的杜鹃亚属(subgen. Rhododendron)和羊踯躅亚属(subgen. Pentanthera)中存在多倍化现象, 甚至存在同一物种有多种倍性。(2)在自然授粉条件下, 除了常见种内杂交及自交情形外, 常绿杜鹃亚属(subgen. Hymenanthes)、杜鹃亚属和映山红亚属(subgen. Tsutsusi)内种间杂交十分普遍, 也有跨亚组之间的自然杂交案例。(3)杜鹃花属植物中自交亲和(self compatibility, SC)与自交不亲和(self incompatibility, SI)现象并存, 云锦杜鹃亚组(subsect. Fortunea)兼具自交败育到高可育性的所有类型, 而在映山红亚属与马银花亚属(subgen. Azaleastrum)中自交不亲和现象则更为常见。通常自交被认为是杜鹃花物种的被动适应, 但对于一些在极端气候条件下分布的局域种而言, 则可能是一种主动响应。(4)不同分类等级(亚属、组和亚组)间的人工杂交研究表明, 杂交亲和性或可育性与双亲的系统发育关系及染色体倍性具有明显的关联, 并反映在发育阶段和各项亲和力指标的变化之中。常绿杜鹃亚属与杜鹃亚属间的远缘杂交相对比较容易, 常绿杜鹃亚属与映山红亚属间、映山红亚属与杜鹃亚属的正反交、映山红亚属与羊踯躅亚属的正交以及常绿杜鹃亚属与羊踯躅亚属的正交、马银花亚属与杜鹃亚属正交等也有亲和的案例。(5)自交不亲和亲本的介入可大幅度增加种间杂交的不育比率, 并导致其由双向可育到单向不育再到双向不育方向发展。     

Two new species of Abrus (Leguminosae-Papilionoideae) from Somalia

The new species Abrus baladensis , from fixed sand dunes near Mogadishu in south-central Somalia, and A. gawenensis , from limestone or sand over limestone in central Somalia, are described.     

A new species of Microcharis (Leguminosae) from Somalia

The new species Microcharis omissa , from the sandstone escarpment near Yasoomman in central Somalia, is described. This apparently narrow endemic is closely related to M. sessilis in north-eastem Somalia.     

New species and combinations in Kleinia (Asteraceae) from the Horn of Africa

The new species Kleinia tuberculata , from open deciduous bushland on gypsum hills and gypseous limestone in northern and north-eastern Somalia, K. curvata , from evergreen bushland on limestone in northern Somalia, K. sabulosa , from deciduous bushland on sand in central Somalia, K. ogadensis , from deciduous bushland in eastern Ethiopia, K. gracilis , from dwarf bushland on limestone in north-eastern Somalia, and K. tortuosa , from alkaline plains in northern Somalia, are described, and for some of them illustrations are provided. The new combinations K. nogalensis and K. lunulata are made, and the recently described K. isabellae from eastern Ethiopia is placed in synonymy of K. lunulata.     

Morphogenesis in Myxococcus xanthus and Myxococcus virescens (Myxobacterales)

1. Myxococcus xanthus B and M. virescens V2 were compared with a view to establishing the control of their morphogenetic cycles. Both organisms are typical myxococci and on solid media with low concentrations of nutrient they form fruiting bodies, within which vegetative cells convert to myxospores. Ultrathin sections of vegetative M. virescens resembled those of M. xanthus and contained prominent heavily stained bodies, presumed to be polyphosphate granules. Shadowed preparations showed fimbriae associated with M. xanthus but not with M. virescens. 2. M. xanthus B converted to myxospores in liquid medium in response to certain alcohols. M. virescens V2 produced phase-refractile spheres, which were not viable and had an unusual ultrastructure. 3. The distributions of fruiting bodies on solid media containing 0.02% Casitone were recorded for the two species and were compared with a Poisson distribution. Cells responded to differences in cell density in a manner suggestive of a response to a chemotactic attractant. Cells growing vegetatively and also cells forming fruiting bodies produced 3',5'-cyclic adenosine monophosphate (cAMP) as measured by the incorporation of exogeneous [3H] adenosine into cAMP. 4. The significance of these findings for theories of fruiting body formation are discussed.     

New species of Cucumis (Cucurbitaceae) from northeast tropical Africa

The new species Cucumis hastatus (widespread in southern Somalia, in deciduous bushlands), C. pubituberculatus (central Somalia, on open coastal dunes), C. Jeffrey-anus (southwestern Somalia and eastern Ethiopia, on alluvial soils), and C. baladensis (south-central Somalia, on fixed dunes), are described and illustrated. C. figarei is shown to be illegitimate, the correct name for the species apparently being C. pustulatus.     

Notes on Tetragonia (Aizoaceae-Tetragonioideae) in Somalia

Tetragonia pentandra , previously believed to be an endemic of Socotra, is reported from northern Somalia. T. retusa sp. nov., a very distinctive endemic of central Somalia with features that partly link Tetragonia and Tribulocarpus , is described and illustrated.     

A new species of Isoglossa (Acanthaceae) from NE tropical Africa

The first species of Isoglossa known from Somalia, I. congesta is described om material from central Somalia and SE Ethiopia. It is related to I. parvifolia Rendle, occurring in E Ethiopia, but differs in the contracted inflorescences and long calyx lobes with long glandular hairs.