Foliar sclereids in Memecylon and Lijndenia (Melastomataceae) from Borneo, Java, Malaya and Sumatra

2014

TAXON

The internal and external transcribed spacers of nuclear ribosomal DNA were sequenced in 167 samples of Memecylon s.str. and 22 outgroup samples of Lijndenia, Mouriri, Spathandra, Votomita, and Warneckea. Maximum‐likelihood analyses of ETS, ITS1, 5.8S and ITS2 alignments yielded tree topologies that are not significantly incongruent, with one exception involving the Tanzanian sample Luke 9741. Monophyly of Memecylon s.str. is strongly supported in the separate ETS and the combined ETS + ITS1 + 5.8S + ITS2 analyses. Also supported in all analyses except 5.8S is a sister‐group relationship between a small species‐group from western and central Africa (Memecylon subg. Mouririoidea, ovary 4‐loculed) and the remaining taxa (M. subg. Memecylon, ovary unilocular). In the combined analysis, internal branches at the base of M. subg. Memecylon are short and weakly supported, yet within this large subgenus one finds a series of monophyletic groups representing different parts of the widespread paleotropical distribution (one group in western and central Africa; two separate groups in East Africa, one of these extending to southern Africa and disjunctly to western and northern Madagascar; one species‐rich group occurring exclusively on Madagascar and the neighboring Comoro and Mascarene islands; and three distinct groups in Indo‐Malesia, one of these also including the Seychelles endemic M. elaeagni). Within the western and central African clade, M. sect. Polyanthema sensu Jacques‐Félix is paraphyletic with respect to M. sect. Afzeliana, and at the morphological level it seems to be a group defined by symplesiomorphies (ovary unilocular, fruit globose). Three East African species (M. fragrans, M. greenwayi, M. semseii) are returned to Memecylon s.str. after being erroneously transferred to Lijndenia by Borhidi. The Madagascan endemic M. mocquerysii is no longer considered a taxonomic synonym of the distantly related, Tanzanian M. cogniauxii. In addition to elevating M. sect. Mouririoidea to subgeneric rank, the following changes are proposed in the infrageneric classification of African Memecylon: (1) the circumscription of sect. Polyanthema is narrowed to comprise only the members of the “M. polyanthemos complex” sensu Jacques‐Félix; (2) Engler's sections Tenuipedunculata, Cauliflora, and Obtusifolia are re‐instated with emended descriptions (in the case of sect. Cauliflora with an expanded circumscription); (3) seven new sections, Buxifolia, Diluviana, Felixiocylon, Germainiocylon, Magnifoliata, Montana, and Sitacylon, are described; (4) the purported occurrence of M. sect. Pseudonaxiandra in East Africa is rejected. A key is provided to the two subgenera and twelve sections currently recognized in African Memecylon. Further study is needed toward a sectional classification of Indo‐Malesian Memecylon, and for revision of the seven Madagascan sections recognized by Jacques‐Félix.

Section: Discussionmentioning

confidence: 99%

“…Mouririoidea Jacq.-Fél. ); and embryo with foliaceous, extensively convoluted cotyledons (Jacques-Félix, 1977, 1978bRao & Jacques-Félix, 1978;Jacques-Félix & Mouton, 1980;Bremer, 1981Bremer, , 1982Rao & al., 1983). The remaining Old World genera, including Spathandra Guill.…”

Section: Introductionmentioning

confidence: 99%

The species‐rich, paleotropical genus Memecylon (Melastomataceae): Molecular phylogenetics and revised infrageneric classification of the African species

2014

TAXON

“…In the treatment of Memecylon sensu lato for the ‘Flora of Tropical East Africa’ (Wickens ), the 10 species with strongly trinervate to multinervate leaves are properly placed in Warneckea (leaf‐lamina smooth) or Lijndenia (leaf‐lamina papillose‐muricate in dried material), whereas the 13 species with apparently uninervate leaves belong to Memecylon sensu stricto. Additional characteristics distinguishing Memecylon sensu stricto from the other memecyloid genera include its leaf surface often appearing roughened (not granular) on drying and fibrous when torn (owing to the presence of filiform to columnar sclereids in the mesophyll); flowers mostly with a ± truncate or sinuate calyx margin, the corolla in bud thus well exposed; uni‐locular (rarely 4‐locular) ovary; and embryo with foliaceous, extensively convoluted cotyledons (Jacques‐Félix , , Jacques‐Félix et al , Rao and Jacques‐Félix , Jacques‐Félix and Mouton , Bremer , , Rao et al ).…”

Section: Memecylon Trunciflorum R D Stone Sp Nov (Fig )mentioning

confidence: 99%

Memecylon trunciflorum sp. nov. (Melastomataceae–Olisbeoideae) from the Udzungwa Mountains, southern Tanzania

Nordic Journal of Botany

2015

Described and illustrated is Memecylon trunciflorum R. D. Stone, an evidently localized endemic of the Udzungwa Mountains in southern Tanzania. The new species was previously confused with the vegetatively similar but distantly related M. erythranthum Gilg and M. semseii A. Fern. & R. Fern., from which it is distinguished by its anther connectives bearing a dorsal oil‐gland and by its ellipsoid to obovoid fruits (vs anther connective gland absent and fruits globose in M. erythranthum and M. semseii). The new species is placed in M. sect. Magnifoliata R. D. Stone together with M. magnifoliatum A. Fern. & R. Fern., from which it differs by its smaller leaves mostly 9.5–15.0 × 3.5–6.0 cm (vs 18–35 × 8–13 cm), transverse veins 8–18 pairs (vs 25–28 pairs), short‐pedunculate inflorescences with secondary axes well developed (vs peduncles and secondary axes absent), white flowers (vs bluish purple), and smaller fruits mostly 11.5–14.5 × 9–11 mm on longer fruiting pedicels 8.0–13.5 mm (vs fruits 17–20 × 12–14 mm on pedicels 5.0–7.5 mm). Despite its local endemism, Memecylon trunciflorum has been assessed as ‘Least Concern’ according to IUCN criteria, although this assessment is dependent on the continued safeguarding of the Udzungwa Mountains National Park.

“…f.) K. Bremer from western and central Africa. The shared characteristics appearing to indicate a close relationship amongst these species include 3-nerved, brown-drying leaves ; ramiform foliar sclereids (Rao & Jacques-Félix, 1978 ;Rao et al, 1983) ; a distinctly 4-lobed calyx with calyx lobes imbricate ; white flowers ; top of ovary lacking interstaminal partitions, the epigynous chamber thus appearing smooth ; small anthers lacking a dorsal oil-gland ; few ovules ; and embryo with rolled cotyledons and a short hypocotyl ( Jacques-Félix, 1977, 1978a, 1978bBremer, 1981). It was further noted that L. laurina is not truly dioecious as reported in Moritzi (1846) but is instead androdioecious (i.e., some trees have male flowers only whilst other trees have hermaphrodite flowers).…”

Section: Introductionmentioning

confidence: 99%

Revised treatment of the genus Lijndenia (Melastomataceae, Olisbeoideae) in Madagascar

2017

Candollea

Lijndenia Zoll. & Moritzi (Melastomataceae, Olisbeoideae) is a small but widespread paleotropical genus of forest shrubs and small trees. In a previous treatment, Jacques-Félix recognized six endemic species of Lijndenia in Madagascar, namely Lijndenia danguyana (H. Perrier) Jacq.-Fél., Lijndenia lutescens (Naudin) Jacq.-Fél., Lijndenia melastomoides (Naudin) Jacq.-Fél., Lijndenia ramiflora Jacq.-Fél., Lijndenia roborea (Naudin) Jacq.-Fél. and Lijndenia terminalis Jacq.-Fél. The present work describes and illustrates three new Madagascan species : Lijndenia acuminata R.D. Stone, Lijndenia darainensis R.D. Stone and Lijndenia densiflora R.D. Stone. The name Lijndenia lutescens (Naudin) Jacq.-Fél. is found to be illegitimate, and a new name Lijndenia memecyloides R.D. Stone is proposed. With these revisions, the flora of Madagascar now holds nine species of Lijndenia, for which a formal taxonomic treatment is provided including a dichotomous key. Lectotypes are designated for Lijndenia danguyana, Lijndenia memecyloides and Memecylon meeusei H. Perrier (treated here as a synonym of Lijndenia memecyloides). The conservation status of each species is assessed according to the IUCN Categories and Criteria. Given the extensive anthropogenic deforestation of Madagascar, one must consider the possibility that Lijndenia acuminata, Lijndenia densiflora, Lijndenia ramiflora and Lijndenia terminalis are already extinct because these four species have not been recollected within the last 50 years. On the other hand, the recent rediscovery of Lijndenia melastomoides is remarkable because this species had not been seen since the year 1954. Résumé