Kaj Vollesen

Phylogenetic Relationships among Acantheae (Acanthaceae): Major Lineages Present Contrasting Patterns of Molecular Evolution and Morphological Differentiation

Abstract We used DNA sequence data from four regions ([1] nrITS; the chloroplast [2] rps16 intron, [3] trnG-S spacer, and [4] trnL-F intron and spacer) to study phylogenetic relationships within tribe Acantheae (Acanthaceae). Our sample includes 18 of 20 recognized genera and 82 of ca. 500 species (plus two Justicieae as out-groups). Results of parsimony and Bayesian analyses were entirely congruent and provided strong support for monophyly of two sub-lineages of Acantheae, referred to here as the ‘one-lipped corolla’ and ‘two-lipped corolla’ lineages, reflecting notable differences in corolla morphology. Subsequent analyses were of the two sublineages separately in order to include all characters (a hypervariable region of trnG-S could not be aligned across the full range of taxa but could be aligned within sublineages). The ‘one-lipped corolla lineage’ comprises six clades of Old World taxa related as follows: [Crossandra (Sclerochiton clade {Cynarospermum [Blepharis (Acanthus clade + Acanthopsis)]})]. All presently recognized genera are strongly supported as monophyletic, except that Blepharis dhofarensis is placed with species of Acanthus, with strong support from both parsimony and Bayesian inference (monophyly of Blepharis was rejected by both parsimony and likelihood). Alternate hypotheses based on calyx and androecial morphology regarding Crossandrella and Streptosiphon could not be rejected, but placement of these genera with some species of Crossandra based on pollen was rejected. The ‘two-lipped corolla lineage’ is strongly supported and includes one clade of Old World plants (the Stenandriopsis clade) that is sister to a strongly supported clade that includes all New World Acantheae as follows: [Stenandrium clade (Neriacanthus {Aphelandra lineage})]. The Aphelandra lineage includes the ‘armed’ Aphelandra clade and a polytomy of six unresolved clades: (1) A. squarrosa, (2) Encephalosphaera clade, (3) Geissomeria clade, (4) A. aurantiaca clade, (5) A. pulcherrima clade, (6) Rhombochlamys. In contrast to patterns in the one-lipped lineage, genera in the two-lipped lineage are mostly not monophyletic nor are relationships among them strongly supported by our molecular data or by morphological synapomorphies. We discuss these results in the context of evidence from other sources including macromorphology, palynology, chromosome numbers, and geographic distribution.

The genus Crossandra (Acanthaceae) in the African continent

The main purpose of this paper is to summarise information gained during work carried out on the genus Crossandra for Flora of Tropical East Africa and Flora Zambesiaca. It was felt that a proper monograph of the whole genus should not be attempted until the Madagascan and Indian species have been studied in full. It was therefore decided that a short synopsis would be an appropriate way to show the present knowledge of the taxonomy of the African species of Crossandra. The present paper deals with all taxa known to occur in Africa and Arabia. Apart from the taxa treated in this paper, there are a further 15-20 species on Madagascar and one species on the Indian subcontinent.

The Old World species of Stenandrium (Acanthaceae: Acantheae)

Summary. The African and Madagascan genus Stenandriopsis is considered synonymous with Stenandrium, a genus hitherto thought to be purely American. Arguments are put forward for transferring Stenandrium from Aphelandreae to Acantheae, a tribe previously thought to have an Old World distribution only. The Old World species of Stenandrium are revised. There are 8 species in Africa and 10 in Madagascar. One species, Stenandrium pauciflorum, is described as new, new combinations are proposed for the other Old World species, and a division of these into three sections is proposed.

Notes on Crossandra (Acanthaceae)

La typification de Cossandra nilotica est clarifiee. Trois nouvelles especes de Somalie et une de Malawi et du Mozambique sont decrites

Three new species of Blepharis (Acanthaceae)

Summary. Blepharis spinescens and B. thulinii from N Somalia and B. petraea from W Tanzania are described and placed in the context of the authors recent revision of the genus. The ecology of B. petraea is discussed in detail.

Two new Tanzanian Acanthaceae

Summary. Two recently discovered species, Crossandra leucodonta and Stenandrium grandiflorum, are described, and their relationship with the other species of the two genera discussed. Since the revisions of African Crossandra (Vollesen 1990) and Stenandrium (Vollesen 1992) collecting in the floristically very rich and to a large extent very poorly known Udzungwa Mts in southern Tanzania has resulted in the discovery of two new species. Crossandra leucodonta Vollesen, sp. nov. C. tridentatae atque C. friesiorum affinis sed bracteis in dimidio apicali albis, in dimidio inferiore tantum viridibus nec per totam longitudinem viridibus differt. Ab eis atque ab omnibus ceteris speciebus africanis Crossandrae sepalo dorsali uninervato tantum et ad apicem attenuato longe aristato, nec e basin binervato neque ad apicem bidentato differt. Typus: Tanzania, FrimodtMoller et al. NG092 (K, holotypus; C, isotypus). Perennial herb, basal part of stems creeping and rooting (eventually dying away from the back), apical part erect, to 15 cm tall; young stems not conspicuously swollen below nodes, sericeous-tomentose with long curly many-celled hairs. Leaves opposite or in pseudo-whorls of 4, dark green above, paler beneath, sparsely sericeouspubescent with many-celled curly hairs along veins beneath, above with scattered hairs on veins and lamina; petiole 0.5 - 1.5 cm long; lamina gradually narrowed below middle, ovate to elliptic, largest 4 - 6 x 2 - 2.5 cm; apex subacute to acuminate, with a more or less well-defined tip; base attenuate decurrent; margin slightly crenate; with 3 - 5 main lateral veins each side. Spikes 1 - 2 cm long, with 2 pairs of sterile bracts at base; peduncle 1.5 - 3.5 cm long, sericeous-tomentose with long many-celled curly hairs. Fertile bracts obovate in outline, dark green with white lobes, 14 - 18 x 5 - 6 mm, basal part with scattered long many-celled curly hairs, apical part of lobes finely puberulous, deeply 3-lobed and lower down also with a single tooth per side, lobes 7 9 x 1 - 2 mm, narrowly triangular, tapering gradually to an acuminate tip. Bracteoles 3 -5 mm long, linear-lanceolate, with a long cuspidate tip, with indumentum as bracts. Sepals glabrous, dorsal 8 - 9 mm long, elliptic with a long cuspidate awn-like tip, 1veined from base, ventral c. 7 mm long, oblong, acuminate, lateral c. 5 mm long, lanceolate. Corolla white or with a faint pale lilac tinge to limb; tube c. 10 mm long; limb c. 9 mm long. Capsule and seed not seen.

Trichaulax (Acanthaceae :Justicieae), a new genus from East Africa

When working on the revision of Megalochlamys and Ecbolium (Vollesen 1989), I was much puzzled by the present species. It obviously has a lot of characters in common with these two genera and especially with Megalochlamys. On the other hand it also possesses several characters not present in any species of Ecbolium and Megalochlamys, not least a most extraordinary pollen morphology (see following paper). At that time the material available to me was not of a sufficient quality to allow a decision about the generic status of the species, and it was therefore decided to let the matter rest. Since then abundant good material has been collected both in Kenya and Tanzania enabling a thorough examination of all the characters considered to be of importance for distinguishing genera inJusticieae: Odontoneminae. This has convinced me that this species is indeed distinct enough for a new genus to be described to accommodate it.

A revision of the African genus Sclerochiton (Acanthaceae: Acantheae)

The genus Sclerochiton Harvey is revised. A total of 19 species is recognised, one of these with 3 subspecies. Five species (S. apiculatus, S. glandulosissimus, S. hirsutus, S. tanzaniensis and S. uluguruensis) are described as new. Two new combinations (S. insignis and S. vogelii subsp. congolanus) are published. An infrageneric system dividing the genus into two subgenera and one of these into five sections is also proposed.

Asystasia (Acanthaceae) in Malaysia

Three taxa of Asystasia, the naming of which has been confused, occur in Peninsular Malaysia. None is native. A. nemorum Nees (syn. A. intrusa Blume, non (Forssk,) Nees) from Java has only been collected from Penang and Singapore. A. gangetica (L.) T. Anderson is widespread and is represented by two subspecies: a large-flowered taxon, subsp. gangetica (syn. A. coromandeliana Nees) which is a long-established introduction from India and a small-flowered taxon, subsp. micrantha (Nees) Ensermu (syn. A. intrusa (Forssk.) Nees) which is a recent introduction, probably from Africa. A key to the three taxa in Malaysia is provided.

Synopsis of the Genus Crossandra (Acanthaceae) in Madagascar

Appreciation of both the perilous state of much of the natural vegetation of Madagascar, one of the most important global centres of biodiversity, and of the urgent need for conservation of remaining areas of undisturbed vegetation has resulted in a large recent increase in botanical exploration of the island. This has resulted in the collection of numerous species new to science as well as many new collections of already-described species. In the Acanthaceae this has meant that many of the generic accounts in the only volume (out of an estimated three) of this family published for Flore de Madagascar (Benoist 1967) have become increasingly out of date. The new material includes many new species, adding to the already rich flora, but also provides material for reconsideration of published species, sometimes leading to a reduction in the number of species recognised. This paper results from the authors increasing frustration at being unable to name adequately an ever-growing number of specimens of the very distinct and conspicuous genus Crossandra. Benoist (1967), in the only previous revision of all the Madagascan species, recognised 16 species. In the present account 8 new species are added, and the existing species are reconsidered resulting in one new combination and the resurrection of one species previously reduced to synonomy. The present paper is a natural continuation of the authors work on the African species of Crossandra (Vollesen 1990a, 1990b), but no attempt has been made to group the Madagascan species into sections as was done (Vollesen 1990b) for the African species. Some of the Madagascan species fall easily within these same sections but others do not. A complete key to all African and Madagascan species with a reconsideration and redefinition of the sections of Vollesen (1990b) will be the object of a future paper.