Almeda, F. & H. Ranarivelo (2018). A new Gravesia (Melastomataceae, Sonerileae) from the Bemangidy-Ivohibe rainforest of southeastern Madagascar. Candollea 73: 1–5. In English, English and French abstracts. DOI:  http://dx.doi.org/10.15553/c2018v731a1

Gravesia parvula Almeda & Ranarivelo (Melastomataceae, Sonerileae), a new species from the Bemangidy-Ivohibe forest of southeastern Madagascar, is described, illustrated, mapped, and compared with superficially similar Malagasy species. In addition to its dwarf rosette-like habit, it is distinguished by the semi-succulent obovate to oblanceolate 1-nerved leaf blades with entire distally repand margins, indumentum of minute dark brown gland-like trichomes that are rounded to shallowly bilobed at the apex, stamens with external (antesepalous) and internal (antepetalous) whorls somewhat unequal in size in each flower, obovoid to oblong anther thecae with cleft-like ventrally inclined apical pores, and capitate stigma. A conservation assessment of “Endangered” is recommended for this species based on IUCN Red List Categories and Criteria.

Morales, J.F. (2018). Studies in the Neotropical Apocynaceae LIV: a synopsis of Asketanthera. Candollea 73: 7–16. In English, English abstract. DOI:  http://dx.doi.org/10.15553/c2018v731a2

This synopsis provides a key, synonymies, descriptions, habitat descriptions, specimens examined, illustrations, maps, and conservation assessment for the four species of Asketanthera Woodson currently recognized. Lectotypes are selected for Asketanthera longiflora Woodson, Asketanthera obtusifolia A.H. Liogier, Echites calycosus A. Rich., Echites picardae Urb. and Echites rugelianus Urb. A neotype is also designated for Echites dolichopetalus Urb. Asketanthera obtusifolia A.H. Liogier is reduced to the synonymy of Pentalinon luteum (L.) B.F. Hansen & Wunderlin.

Castillon, J.-P. & J.-B. Castillon (2018). Notes on Euphorbia sect. Denisophorbia (Euphorbiaceae) in Madagascar: description of a new species and a new synonymy. Candollea 73: 19–25. In French, English and French abstracts. DOI:  http://dx.doi.org/10.15553/c2018v731a3

The identity of the poorly known species Euphorbia commersonii Baill. (Euphorbiaceae) is clarified. This species occurring in the Fort-Dauphin region (in the Southeast of Madagascar) is assigned to Euphorbia sect. Denisophorbia (Leandri) Croizat. Formerly considered as a later synonym of Euphorbia thuarsiana Baill., Euphorbia commersonii is reinstated and Euphorbia elliotii Leandri is considered as a later synonym. A lectotype is designated for the latter species. Euphorbia neoelliotii J.-P. Castillon & J.-B. Castillon, belonging to the same section, is described and illustrated. This new species is distinguished from Euphorbia commersonii by its more elongated and much less coriaceous leaves and its incyathescences with short green peduncles bearing a single green cyathium with tiny cyathophylls appressed to the involucre.

Applequist, W.L. (2018). A revision of Homalium sect. Odontolobus (Salicaceae) endemic to Madagascar. Candollea 73: 27–48. In English, English and French abstracts. DOI:  http://dx.doi.org/10.15553/c2018v731a4

Homalium sect. Odontolobus Warb. (Salicaceae) is endemic to Madagascar and formerly included three species. In this revision, nine species are recognized, three of them newly described (Homalium densispicatum Appleq., Homalium masoalense Appleq., Homalium ovatifolium Appleq.) and three transferred from Homalium sect. Blackwellia Benth. Homalium densispicatum has highly reduced flowers like those of Homalium moniliforme H. Perrier, but the leaves are larger and the inflorescences thicker, with flowers in elongated many-flowered glomerules. Homalium masoalense and Homalium ovatifolium are northern species that have frequently ovate leaves and long styles and filaments; the flowers of Homalium masoalense are larger, with longer sepals, while Homalium ovatifolium has often canescent inflorescences. Two new subspecies are described: Homalium moniliforme subsp. littorale Appleq. and Homalium planiflorum subsp. roseiflorum Appleq. A key for identification of the species of Homalium sect. Odontolobus is provided.

Edelman, S & J.H. Richards (2018). Morphology and architecture of the threatened Florida palm Acoelorrhaphe wrightii (Arecaceae: Coryphoideae). Candollea 73: 49–59. In English, English abstract. DOI:  http://dx.doi.org/10.15553/c2018v731a5

Rhizomatous palms are economically and ecologically important, but few studies on their growth and architecture have been published. The purpose of this study was to describe morphology, growth and architecture of Acoelorrhaphe wrightii (Griseb. & H. Wendl.) Becc. (Arecaceae: Coryphoideae), a rhizomatous circum-Caribbean wetland palm. The study was conducted on cultivated individuals at two botanical gardens in Florida, USA. Leaf morphology, stem height and circumference, lamina length, width and pinna number, and petiole length and width were measured on 2 ramets of 16 genets. Ramet growth rates were determined by recording leaf production per ramet every 3 months for 2 years on 2 ramets of 38 genets. Genet circumference, diameter, and number of ramet tiers, plus number of living ramets > 0.5 m, were measured on 41 genets. Ramets have an establishment period from inception to 0.3 m ramet height. This establishment phase is reflected in leaf morphology, leaf production and rhizome growth. Plant growth varies seasonally, with greater leaf production in the warmer wet season and less in the cooler dry season. Clonal architecture was consistent across gardens and populations. This study quantifies growth and the architectural potential for this species and highlights the importance of botanical gardens for research on long-lived, slow-growing species such as many palms.

Jeanmonod, D. (2018). Typification of the corsican names of taxa of the Burnat Herbarium (G-BU). Candollea 73: 61–74. In French, English and French abstracts. DOI:  http://dx.doi.org/10.1553/c2018v731a6

The Burnat herbarium (G-BU) is essential for the study of the Corsican flora but remains poorly known. A search for all the new names for Corsica and the associated original material used by various authors for their descriptions and present in this closed herbarium was carried out by various methods. Ninety eight names of taxa from Corsica were highlighted and 197 herbarium collections considered as original material were located. They correspond to the description of 9 species, 88 infraspecific taxa and 1 hybrid belonging to a broad taxonomic spectrum (26 families and 56 genera). Thirteen authors made these descriptions, mainly John Briquet (66 taxa), Eduard Hackel (7), Casimir Arvet-Touvet (6) and René Verriet de Litardière (5). Among the type specimens, 48 are holotypes, 44 are lectotypes of which 39 are designated in the article, 7 are isotypes and the remaining represents syntypes. The exhaustive list of these names of taxa, their respective typification as well as their currently accepted names are provided.

Jeanmonod, D. (ed.) (2018). Notes on Corsican flora, XXVI. Candollea 73: 75–90. In French, English and French abstracts. DOI:  http://dx.doi.org/10.15553/c2018v731a7

These “notes” deal with 47 noteworthy taxa amongst which 10 are new to the island's flora. Two of these taxa are native: Equisetum× moorei, Dactylorhiza sambucina x D. saccifera, and 8 are introduced: Lemna minuta, Alopecurus rendlei, Cenchrus setaceus, Baccharis halimifolia, Cota tinctoria, Schkuhria pinnata, Brassica tournefortii and Saururus cernuus. One family is new for the island: Saururaceae. However Lolium remotum must be deleted from the Corsican Flora due to a missidentification. New localities are given for 17 taxa considered as “very rare” (RR) out of which 3 become “rare” (R) on the one hand, and for 12 taxa considered to be “rare” (R) out of which 5 change their status from “rare” to “not common” (PF) on the other. Finally, the data published for the 7 remaining taxa constitute a considerable increase of our knowledge about their distribution to new sectors, mainly the Cagna one. Seven out of 47 taxa are endemic, 7 are protected and 15 are xenophytic species.

Schatz, G.E. & P.P. Lowry II (2018). Novitates neocaledonicae. IX. Taxonomic notes on New Caledonian Diospyros (Ebenaceae) with new synonymy and the description of two new species. Candollea 73: 91–100. In English, English and French abstracts. DOI:  http://dx.doi.org/10.15553/c2018v731a8

A review of the taxonomy of Diospyros L. (Ebenaceae) in New Caledonia results in the description of two new species and the placement in synonymy of six species previously recognized in the treatment of Ebenaceae for the Flore de la Nouvelle-Calédonie et Dépendances. Diospyros hequetiae G.E. Schatz, Lowry & Fleurot and Diospyros rufotomentosa G.E. Schatz & Lowry are described and illustrated with line drawings and field photographs, accompanied by a distribution map. Risk of extinction assessments indicate that Diospyros hequetiae is “Endangered” and Diospyros rufotomentosa is “Near Threatened”. A lectotype is designated for Diospyros samoensis A. Gray.

Negaresh, K. (2018). A new combination in the genus Cyanus (Asteraceae, Cardueae, Centaureinae). Candollea 73:101–103. In English, English abstract. DOI:  http://dx.doi.org/10.15553/c2018v731a9

Cyanus raimondoi (Bancheva & Kaya) Negaresh is proposed as a new combination. It is morphologically similar to Cyanus eflanensis Kaya & Bancheva, but differs from it by the indumentum, the flowering stem, the cauline leaves, and the achenes dimension.

Bernardi, L.^† (2018). Taxonomic novelties in Nectandra Rottb. and Ocotea Aubl. (Lauraceae) of the Flora of Paraguay. Candollea 73: 105–108. In Spanish, English and Spanish abstracts. DOI:  http://dx.doi.org/10.15553/c2018v731a10

Seven species of Lauraceae for the Flora of Paraguay are recircumscribed and compared with their close parents: Nectandra angustifolia (Schrad.) Nees & Mart., Nectandra briquetii Hassl., Nectandra megaphylla Hassl., Ocotea catharinensis Mez, Ocotea floribunda (Sw.) Mez, Ocotea gracilipes Mez and Ocotea suaveolens (Meisn.) Hieron. Five new synonyms are proposed.

Ramella, L. & G. Barriera (2018). Typifications in the Lauraceae family of the Flora of Paraguay. Candollea 73: 109–113 In Spanish, English and Spanish abstracts. DOI:  http://dx.doi.org/10.15553/c2018v731a11

The typification of 15 names described in the Lauraceae family from Paraguayan collections in the genera Aiouea Aubl., Nectandra Rottb., Ocotea Aubl., Oreodaphne Nees & Mart. and Phoebe Nees is presented. Lectotypes are designated for: Nectandra lanceolata var. paraguariensis Hassl., Ocotea confusa Hassl., Ocotea gracilipes Mez, Ocotea lanceolata f. latifolia Hassl., Ocotea suaveolens var. robusta Hassl. and Oreodaphne suaveolens Meisn. A second step lectotypification is made for Nectandra megaphylla Hassl.

Callmander M.W. & S. Buerki (2018). A new species and a new synonym in Pandanus subg. Rykia (Pandanaceae) in Thailand. Candollea 73: 115–120. In English, English abstract. DOI:  http://dx.doi.org/10.15553/c2018v731a12

The genus Pandanus Parkinson (Pandanaceae) has never been critically revised in Thailand. Most species belong to the taxonomically challenging Pandanus subg. Rykia (Vrise) B.C. Stone. Recent field observations coupled with a review of herbarium material of Thai Pandanaceae (serving as a backbone for the forthcoming family treatment for the Flora of Thailand) have revealed new findings enabling better understanding the taxonomy of Pandanus species in this region. In this article, we formally synonymize Pandanus bifidus H. St. John under Pandanus obconicus H. St. John, two species among the fifteen that Harold St. John described from Thailand in 1963 and 1965. We also describe a new species, Pandanus voradolii Callm. & Buerki, restricted to north-eastern Thailand. The new species resembles Pandanus obconicus in its acaulescent low shrub habit, but differs in its ecology, shape and texture of its leaves, the length of its peduncle and shape and dimensions of its syncarp. Field photographs and a preliminary risk of extinction assessment is provided for the new species.

Received: March 3, 2018. Accepted: April 19, 2018. First published online: June 25, 2018.

Gautier, L. & Y. Naciri (2018). Three Critically Endangered new species of Capurodendron (Sapotaceae) from Madagascar. Candollea 73: 121–129. In English, English and French abstracts. DOI:  http://dx.doi.org/10.15553/c2018v731a13

Three new species in the Malagasy endemic genus Capurodendron Aubrév. (Sapotaceae) are described and illustrated. Their preliminary conservation status according to the criteria of IUCN is provided. Capurodendron schatzii L. Gaut. & Naciri is a large-laeved evergreen tree from the humid forest east of the Masoala peninsula. The new species is compared with the other large-leaved species of the genus. Capurodendron sahafariense L. Gaut. & Naciri is a deciduous small-leaved tree of medium size from dry forests on sandy soils in the extreme North. It shares with Capurodendron costatum Aubrév. a 5-ridged fruit, but differs by its much smaller leaves. As it name implies, Capurodendron nanophyllum L. Gaut. & Naciri has the smallest leaves encountered in the genus. It is a shrub found near Tsihombe in the extreme south, the driest part of the island, within the range of the variable Capurodendron androyense Aubrév. The differences between the two taxa are highlighted. All three species are preliminary assessed as “Critically Endangered”.

Callmander, M.W. & P.B. Phillipson (2018). New combinations and typifications in Vitex (Lamiaceae) from Madagascar. Candollea 73: 131–136. In English, English and French abstracts. DOI:  http://dx.doi.org/10.15553/c2018v731a14

The genus Vitex L. (Lamiaceae) is pantropical and comprises c. 250 species, of which 42 are currently accepted for Madagascar, all endemic to the country, but one. A number of the Malagasy species of Vitex have been treated as comprising infraspecific taxa, including Vitex betsiliensis Humbert and Vitex cauliflora Moldenke (two subspecies and three varieties respectively), which are the subject of this note. We have undertaken a thorough review all of the available specimens in the herbaria at G, MO and P to gain a better understanding of the morphological variations of both species, and we conclude that the five intraspecific taxa each represent distinct species. We therefore provide the necessary new combinations: Vitex barorum (Humbert) Callm. & Phillipson and Vitex villossisima (Moldenke) Callm. & Phillipson, and the new name: Vitex humblotiana Callm. & Phillipson. Each of the five species is provided with notes on their morphological affinities and with risk of extinction assessments following the IUCN Red List Categories and Criteria.