Staminal Corona Research Articles

Matelea tarrazuana (Apocynaceae, Asclepiadoideae), a new critically endangered ocellate species from Central Pacific of Costa Rica

Matelea tarrazuana, a new species endemic to Costa Rica, is described and illustrated. It is similar to M. pusilliflora, a vine from Yucatan Peninsula because of its green flowers with a reflective white spot in the apex at the apex of each lobe, but differs from that species by its longer pedicels, larger corolla lobes, staminal corona purple (vs. orange), gynostegium with the style apex purple (vs. green) and inhabiting premontane forests of Costa Rica. Data on its distribution and habitat, phenology, conservation status and taxonomy are included, as well as photographs of the living plant, and a key to identify the five related species in Mesoamerica.

Peliosanthes longiracemosa (Asparagaceae), a new species from limestone areas of northern Vietnam

Peliosanthes longiracemosa, a new species from limestone areas of northern Vietnam, is described and illustrated. It is most similar to P. macrostegia in having a distally incurved staminal corona and a distinct pyramidal style, but clearly distinguishable chiefly by the broader leaf blades with more longitudinal veins and closer transverse veinlets, relatively longer, more slender raceme, more numerous widely expanded flowers with recurved perianth segments, and more incrassate, depressed globose staminal corona. Information on the habitat and phenology as well as notes on the taxonomic relationships with other congeners is also provided.

Hemipogon trilobatus sp. nov. (Apocynaceae: Asclepiadoideae), a new microendemic from Chapada dos Veadeiros, Central Brazil

Hemipogon s. str. (Apocynaceae: Asclepiadoideae) currently consists of three species sharing an erect herbaceous habit, narrow leaves and corona-less flowers with urceolate, internally bearded corolla, that are mainly distributed in savannahs of the Cerrado biodiversity hotspot, South America. Here, we describe and illustrate a new species of Hemipogon, H. trilobatus Bitencourt & Rapini sp. nov., from an open savannah in Chapada dos Veadeiros, Central Brazil. Hemipogon trilobatus sp. nov. differs from the other species of the genus mainly by the presence of a reduced staminal corona with 3-lobed lobes, but also by opposite leaves and triangular anthers. Distribution and habitat data, as well as a key and a comparative table to distinguish the four species currently accepted in Hemipogon s. str., are provided. Based on criteria B2ab(i,ii,iii,iv) of the International Union for Conservation of Nature (IUCN), the species is provisionally assessed as Critically Endangered.

Peliosanthes cupuliformis (Asparagaceae), a new species from central Laos

We describe a new species, Peliosanthes cupuliformis, from central Laos with photographic illustrations and relevant taxonomic data. The species appears to be a local endemic confined to a karstic limestone area of Khammouane Province (Boualapha District). It is readily distinguishable from all other congeners by a suit of unique traits such as the dwarf habit, laterally revolute perianth segments, short truncate annular or cup‐shaped staminal corona, and broadly conoid pistil with a centrally slightly sunken stigma. Its relationship to P. divaricatanthera known from central Vietnam and Yunnan, China, is briefly discussed. A preliminary identification key to all the species of Peliosanthes so far known from Laos is also provided.

Peliosanthes macrophylla var. assamensis (Asparagaceae), a new variety from Behali Reserve Forest in Assam, Northeast India

Peliosanthes macrophylla var. assamensis, a new variety from Behali Reserve Forest in Assam, Northeast India, is described with accompanying photos and relevant taxonomic data. It differs from var. macrophylla from Arunachal Pradesh and Sikkim, Northeast India, mainly by the staminal corona internally protruding near the middle (vs internally upright corona without a particular inward protrusion), shorter anthers somewhat divergent distally (vs nearly upright anthers), and longer, papillulate pistils exceeding the anthers (vs glabrous pistils not exceeding the anthers).

A new species of Dischidia (Apocynaceae, Asclepiadoideae) from North-eastern Thailand.

Dischidia phuphanensis Chatan & Promprom, a new species from north-eastern Thailand, is described and illustrated. The new species is similar to D. tonkinensis Costantin, but is distinguished by the shape of its leaves, the apices of the staminal corona lobes, the colour of the corolla and the absence of a corolline corona. The distinguishing characters of similar species are discussed. A key for the identification of those species in Thailand without pitcher-like leaves is provided.

Transfer of Cuban Marsdenia to Ruehssia (Apocynaceae–Asclepiadoideae), and two new species in Ruehssia

The cosmopolitan genus Marsdenia R. Br. in its conventional circumscription has been shown to be strongly polyphyletic, with all New World species grouping in a single clade. Therefore, the genus Ruehssia H. Karst. was recently reinstated to encompass the 42 Brazilian species, initially. In the present study, the nine Cuban species currently classified under Marsdenia are transferred to Ruehssia, and two species, R. lindenii and R. yamanigueyensis, both endemic to Cuba, are described as new. Ruehssia yamanigueyensis is characterized by very thin, wiry stems and small leaves and flowers, while R. lindenii is like R. clausa in habit, but differs strongly in the shape of the staminal corona. Illustrations and a distribution map for two new species are provided, as well as a key to all Ruehssia species on Cuba. Lectotypification is performed where necessary.

<p><strong><em>Peliosanthes crassicoronata </em></strong><strong>(Asparagaceae), a new species from southern Vietnam</strong></p>

Peliosanthes crassicoronata is described and illustrated as a new species from southern Vietnam. It somewhat resembles P. macrostegia in having drooping bowl-shaped purplish flowers, but is readily distinguishable by the larger leaves with more numerous longitudinal veins, internally thickly ribbed staminal corona, and pistil with a hexagonal ovary and an indistinct style. The phylogenetic relationship of the new species was inferred from an analysis of chloroplast and nuclear DNA sequences.

Hoya amicabilis sp. nov. (Apocynaceae, Asclepiadoideae), from Java discovered on Facebook

A new species from Java, Hoya amicabilis S.Rahayu & Rodda is described and illustrated. It was first identified as a new species from pictures posted on social media in 2017. Hoya amicabilis is part of a small group of species that have an unusual shrubby habit, but it is the only one in that group with bright yellow campanulate flowers. Furthermore, Hoya amicabilis is a rather unusual species of Hoya since its staminal corona lobes are oblong, erect, while most species of Hoya have well‐developed generally spreading corona lobes, and its style head is umbonate, brightly coloured and extending above the anther appendages, while most species have a conical style head covered by anther appendages.

<p><strong><em>Heterostemma barikiana</em> (Apocyanceae, Asclepiadoideae), a new species from India, Myanmar and Thailand</strong></p>

A new species of Heterostemma, H. barikiana, is described and illustrated. The new species is similar to Heterostemma xuansonense in the absent or very reduced peduncle and in the presence of a pubescent staminal corona.

<p><strong>Two new species of Peruvian Amaryllidaceae, an expanded concept of the genus <em>Paramongaia</em>, and taxonomic notes in <em>Stenomesson</em></strong></p>

A new species of Paramongaia, P. multiflora, and of Rauhia, R. albescens, are described from Peru. We also present an updated parsimony analysis of aligned ITS sequences across the tetraploid Andean clade of Amaryllidaceae subfam. Amaryllidoideae that places both the new species and the only other species known of Paramongaia into a clade within the tribe Clinantheae with three erstwhile species of Clinanthus. We propose an expanded concept of the genus Paramongaia, conserved over Callithauma, for all five species, provide a neotype for Paramongaia viridiflora, and make the necessary combinations in the genus. Paramongaia is morphologically delimited from Clinanthus by the erect, uniformly glaucous leaves, the fusion of the spathe bracts on one side or proximally, the short pedicels, and the insertion of the free filaments below the rim of the staminal corona. A key to the species of Paramongaia is provided. We additionally present some taxonomic notes for the genus Stenomesson.

Heterostemma ficoides (Apocynaceae: Asclepiadoideae), a new species with fig-like flowers from Northern Thailand

Heterostemma ficoides A.Kidyoo, a new species of Heterostemma sect. Oianthus with a fig-like flower discovered in northern Thailand is here described. Photographs, line illustrations and detailed comparison with the similar species, H. vasudevanii Swarupan. & Mangaly are provided. Heterostemma ficoides resembles H. vasudevanii in having a fleshy globose flower and the presence of the inner corona appendages, but clearly differs in leaf shape, leaf venation, presence of dense hairs on the outer and inner surfaces of the corolla, and apex of the staminal corona lobes. An identification key to the species of sect. Oianthus is presented.

A new species of Dischidia (Apocynaceae: Asclepiadoideae) from the limestone hills of southern Thailand

A new lithophyte growing on karst in southern Thailand, D. thaithongiae Kidyoo is here described and illustrated. Its vegetative and reproductive morphological characters are compared with those of the similar D. kerrii. Both species have slender stems and branches with oblong‐elliptic to oblong‐lanceolate leaves, a ring of long white hairs in the throat of the corolla tube and vestigial staminal corona lobes that are not anchor‐shaped. However, the new species is clearly distinguished by the presence of a corolline corona and the shape of the staminal corona lobes.

Peliosanthes longicoronata (Asparagaceae), a new species from central Vietnam

Peliosanthes longicoronata is described and illustrated as a new species from central Vietnam (Ha Tinh Province, Vu Quang National Park). The new species has comparatively long staminal corona, that is mentioned in the specific epithet. The new species resembles P. teta, but differs in its solitary, upward-facing flowers and a white, tubular, distally incurved staminal corona.

A revised, phylogenetically-based concept of Ceropegia (Apocynaceae)

Recent phylogenetic reconstructions in the Ceropegieae (Apocynaceae-Asclepiadoideae) show that the 357 species of highly succulent stapeliads and four lineages of the 141 species of Brachystelma R.Br. ex Sims are nested within the 219 species of Ceropegia L.The stapeliads, shown convincingly to be nested within Ceropegia, are primarily characterized by their non-climbing, highly succulent, tuberculate stems with fleshy flowers with a mostly short corolla-tube. However, highly succulent, tuberculate stems are not restricted to the stapeliads and are present in four lineages of Ceropegia. Furthermore, tubular flowers are also found among the stapeliads and are not restricted to Ceropegia. Since a slender, tubular corolla is extremely homoplasious within Brachystelma, Ceropegia and the stapeliads, we move away from this as defining Ceropegia to recognize some sections in which there is a range from slender, tubular flowers to almost flat flowers.To re-establish a monophyletic Ceropegia, we propose a new classification in which Brachystelma and all genera of the stapeliads are placed in a greatly enlarged Ceropegia. This new concept of Ceropegia is defined by the lack of hard, wiry roots, the softly fleshy tissue of the peduncles and pedicels, the absence of any corolline corona, the presence of two well-developed series of the staminal corona and the presence of a compitum in the style-head leading to the fertilization of both ovaries. We transfer the species of Brachystelma into several sections of Ceropegia and reduce the 31 stapeliad genera to sections of Ceropegia, after which Ceropegia has 63 sections. Sect. Chamaesiphon H.Huber is the largest with 115 species, two sections among the stapeliads each contain over 50 species but the remaining sections are mostly considerably smaller. We provide diagnostic descriptions, lists of included species and distributions for each of the subdivisions that we recognise. Over 400 new combinations are made in Ceropegia.

Pollinia transfer on moth legs in Hoya carnosa (Apocynaceae).

The genus Hoya (Apocynaceae; Asclepiadoideae) is characterized by a set of complex floral characters unique among the asclepiads, but their role in pollination is poorly understood. Here, we report a new mechanism of asclepiad pollination in the wax plant Hoya carnosa: the pollinaria are transferred on the legs of medium or large settling moths. Floral visitors and their behavior were observed on Amami-Oshima Island during 2013-2015, and the efficacy of different pollinators was determined by counting the pollinarium loads on different flower visitors. The floral characters were studied to establish the process of pollination in relation to pollinator behavior on the flower. Hoya carnosa was visited by various settling moths at night, but pollinia attachment was confirmed predominantly on the legs of the large moth Erebus ephesperis (Noctuidae) and less frequently on the legs of the medium-sized moths Bastilla arcuata (Crambidae) and Cleora injectaria (Geometridae). The moths walked around and searched for nectar on the inflorescence, and the corpusculum became clipped to the arolia (adhesive pads on moth tarsi) as they stepped on the pollinaria between the staminal corona. The downward spherical inflorescence of aggregated flowers with flat, velvety petals and a slippery corona provides restricted footholds for the visitors, which efficiently leads pollinator legs to the pollinaria. Although the pollination system of Hoya is largely unknown, pollination by insect legs may be a major pollination system in this genus because these basic floral characters are shared among many species.

Periglossum podoptyches (Apocynaceae-Asclepiadoideae), a new species from KwaZulu-Natal province, South Africa

Periglossum podoptyches is described as a new species from the KwaZulu-Natal Province of South Africa. As a rare species its conservation status is assessed as Vulnerable. This new species is closely related to both Periglossum mackenii and P. kassnerianum from which it differs mainly in having folded flaps of tissue at the base of the face of the restricted basal stalk of the staminal corona lobes. A comparative table with diagnostic morphological features and a key to the species of Periglossum are provided.

Two new species of endemic Ecuadorean Amaryllidaceae (Asparagales, Amaryllidaceae, Amarylloideae, Eucharideae).

New species of the genera Stenomesson and Eucharis (Amaryllidaceae) are described from Ecuador. Stenomesson ecuadorense is the second species of the genus reported from that country, and the only endemic one. It is related to Stenomesson miniatum and Stenomesson campanulatum, both from Peru, with which it shares orange flower color and the fusion of the staminal corona to the perianth tube. It differs from Stenomesson miniatum by the non-urceolate perianth, from Stenomesson campanulatum by its shorter stamens and longer perianth, and from both by its lower montane, cloud forest habitat. Eucharis ruthiana, found in the vicinity of Zamora, is related to Eucharis moorei from which it differs by the narrower leaves and tepals; short, deeply cleft staminal corona; the long teeth on either side of the free filaments; the narrowly subulate, incurved free filaments; and the shorter style. The green mature fruit and campanulate floral morphology place it in Eucharis subg. Heterocharis.

<I>Hoya corymbosa</I> (Apocynaceae, Asclepiadoideae), a New Unusual Species from Sabah, Borneo, and its Systematic Position based on Phylogenetic Analysis

Abstract A new species, Hoya corymbosa, from Sabah (Borneo), is described and illustrated. It is a horizontally growing epiphytic shrub with diminutive flowers. Its minute staminal corona lobes lacking revolute outer margins and broad, flat caudicles of the pollinarium (resembling those of Dischidia) are quite peculiar within the genus, which is otherwise characterized by corona lobes with revolute margins and generally round to oval caudicles. Its position in Hoya has been confirmed by phylogenetic analysis based on nuclear ribosomal ITS region, the matK gene and psbA-trnH intergenic spacer.

Hoya devogelii(Apocynaceae Asclepiadoideae), a new species from kerangas heath forests in Sarawak, Borneo

Summary The new species Hoya devogelii Rodda & Simonsson with campanulate corollas from kerangas montane forest of Sarawak, Borneo is here described and illustrated. This species differs from any previously described species of Hoya in the very pubescent corolla and the staminal corona with a very developed process forming a ring around the base of the corona lobes. Morphological affinities between H. devogelii and other campanulate flowered species of Hoya from Borneo are discussed.