Didymoglossum radiatum: A new species of creeping Fern from Thailand.

The genus Didymoglossum comprises about 30 species of small, generally tropical Ferns growing as epiphytes (i.e. on other Plants) or epiliths (on rocks). Roughly half of the described species come from the Old World, with eight species from tropical Asia. Five species of Didymoglossum are known from India, five from China, one from Vietnam, four from the Solomon Islands, and six from Malesia (Malaysia, Brunei, the Philippines, and western Indonesia). These Ferns, and possibly other, undescribed species, are likely to also be found in the nations between these documented areas, though as yet few, if any, studies have been carried out in these countries.

In a paper published in the journal PhytoKeys on 6 August 2025, Siwakorn Chokrassameehirun of the Department of Horticulture at Kasetsart University, Ekaphan Kraichak of the Department of Botany and Biodiversity Center at Kasetsart University, and Tassanai Jaruwattanaphan, also of the Department of Horticulture and Biodiversity Center at Kasetsart University, present a study of the genus Didymoglossum in which they describe a new species, as well as documenting other species in the country for the first time.

The new species is described from specimens collected in Hala–Bala Wildlife Sanctuary in Waeng District in the far south of Peninsula Thailand, close to the border with Malaysia. The species is named Didymoglossum radiatum, in reference to the false veinlets on the fronds of the Fern, which form a radiating pattern. 

Didymoglossum radiatum. (A) Habit; (B) Raised sori of fertile Plants; (C) Adaxial surface of sterile fronds; (D) Abaxial surface of sterile fronds; (E) False veinlet construction; (F) Sori. Siwakorn Chokrassameehirun in Chokrassameehirun et al. (2025).

Didymoglossum radiatum can be epiphytic or epilithic in nature, with a long, creeping rhizome 0.2-0.3 mm in diameter firmly anchored to the surface over which it grows by numerous dark brown hairs. It produces plate-like fronds 1.0-1.5 mm in diameter, with dense brown hairs around the rims. Each frond typically bears a single sori (spore-producing body).

Illustration of Didymoglossum radiatum. (A) Fertile frond; (B) Sterile fronds; (C) False veinlet construction; (D)–(E) Sori with tubular involucres; (D) Sori with filiform receptacle; (E) Sori borne at the notch of the frond. Siwakorn Chokrassameehirun in Chokrassameehirun et al. (2025).

Chokrassameehirun et al. also record the presence of two species of Didymoglossum in Thailand for the first time. 

The first of these is Didymoglossum henzaianum, a species which grows on rocks close to streams, which was first described from Myanmar in 2014, and which has subsequently been reported in India, Vietnam, and Peninsula Malaysia. Chokrassameehirun et al. found specimens of this species in Phu Ruea District in Loei Province, in the north of the Country.

Didymoglossum henzaianum. (A) Habit; (B) Fertile plants; (C) False veinlets on lamina segment; (D) Sori with obconic–tubular involucres. Siwakorn Chokrassameehirun in Chokrassameehirun et al. (2025).

The second new report is of Didymoglossum mindorense, a species described in the Philippines in 2006, and subsequently reported from Borneo, New Guinea, the Solomon Islands, and Queensland. Didymoglossum mindorense is found at low elevations, and typically close to streams. It is usually found growing around the bases of trees, but will sometimes colonise rocks. Chokrassameehirun et al. reporr specimens of this species in Hala–Bala Wildlife Sanctuary and the area around it.

Didymoglossum mindorense. (A) Habit; (B) Fertile fronds; (C) Lobe of sterile frond; (D) Fertile frond. Siwakorn Chokrassameehirun in Chokrassameehirun et al. (2025).

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Prunus luxurians: A new species of Cherry from southwestern Ecuador.

The genus Prunus has a worldwide distribution and contains several important food crops (including Cherries, Almonds, and Plums), ornametal species (Blossom Cherries), timber souces (e.g. Black Cherry) and medicinal Plants (e.g. African Cherry). There are thought to be about 450 valid species in the genus, but the situation is complicated with about 1230 species described within the genus, and over 2000 more in other genera that have since been synonymised with it (i.e. genera which have had all their putative members moved into Prunus. 

Historically, it has been thought that the majority of Prunus species are found in the northern temperate belt, with a smaller number of species found at high altitudes in tropical and subtropical zones. However, recent research has discovered that the genus is much more widespread in lowland tropical forests than previously realised, particularly in the Americas, raising the possibility that the genus is more diverse in these regions than in the temperate zone.

In a paper published in the journal PhytoKeys on 4 April 2025, Álvaro Pérez of the Herbario QCA at the Pontificia Universidad Católica del Ecuador, Jorge Andrés Pérez-Zabala of the Herbario Gabriel Gutiérrez Villegas at the Universidad Nacional de Colombia, Katya Romoleroux, also of the Herbario QCA at the Pontificia Universidad Católica del Ecuador, David Espinel-Ortiz, again of the Herbario QCA at the Pontificia Universidad Católica del Ecuador, and of the Bonn Institute of Organismic Biodiversity at the University of Bonn, and Chaquira Romoleroux and Natasha Albán-Vallejo, once again of the Herbario QCA at the Pontificia Universidad Católica del Ecuador, describe a new species of Prunus from southwestern Ecuador.

The new species is described from a small population of trees discovered in a cloud forest remnant in the Sambotambo Birón area of the Jocotoco Foundation-managed Reserve Buenaventura in El Oro Province, on the western flank of the Andes, between 1300 and 1400 m above sealevel. The new species is named Prunus luxurians, in reference to its 'profuse blooming and outstanding beauty', which makes it a conspicuous part of the lower and mid-strata of the forest.

Prunus luxurians: (A) Habit, (B branch with leaves and floriferous shoots, (C) flowers. Álvaro Pérez in Pérez et al. (2025).

Prunus luxurians forms trees up to 11 m high, with grooved dark brown bark with lighter lenticles (raised pores). Leaves are oblong-to-lance-shaped, waxy, and grow on alternating sides of leaf stems, they are 10–13.65 cm long and 3.5–4.65 cm wide. Flowers are white with light green centres, and born on floriferous shoots, which can have 14–27 individual flowers, clusetered together in groups of 3-4.

Only five living trees were found, in a fragment of montane evergreen forest, with high levels of bith diversity and endemism. The remaining forest fragments in this region are considered to be threatened by mining and farming activities, for which reason Pérez et al. recomend that Prunus luxurians be classified as Critically Endangered under the terms of the International Union for the Conservation of Nature's Red List of Threatened Species.

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Boswellia hesperia: A new species of Dwarf Frankincense from Socotraa Island.

Frankincenses, Boswellia spp., are trees and small shrubs noted for the aromatic resin they produce, found in East Africa, Arabia, and parts of South Asia. In 1971 Frank Nigel Hepper of Kew Royal Botanic Gardens described a Dwarf Frnakincense, Boswellia nana, from the Yemeni island of Socotra in the Indian Ocean (a noted hotspot for botanical endemism). In 2004, botanists Anthony Miller and Miranda Morris reported a second species of Dwarf Frankincense from Socotra, something which several subsequent studies have also recorded, but which has not, to date, been formally described.

In a paper published in the Nordic Journal of Botany on 20 February 2025, Mats Thulin of the Department of Organismal Biology at Uppsala University, Michael Weber from Bad Berka in Germany, Sami Ali Mohammed Mubarak from Socotra Island, and Alain Rzepecky from São Brás de Alportel in Portugal, formally describe the second species of Socotran Dwarf Frankincense.

The new species is named Boswellia hesperia, where 'hesperia' means 'west', the species having been found exclusively at the western end of the Island of Socotra; this is in contrast to Boswellia nana, which is found exclusively at the eastern end of the island. Boswellia hesperia is an entirely prostrate dwarf species, found growing within holes and crevasses in limestone rock. This habit is also seen in Boswellia nana, although that species sometimes also produces dwarf shrubs up to 2 m high. Boswellia hesperiai also differs from Boswellia nana in its leaves, which are waxy above, but covered in white fur below, whereas those of Boswellia nana are waxy on both sides.

Boswellia hesperia from mountain ridge above Neet, 5–6 km from the coast, Socotra, 18 May 2021. (A) plant filling out crevice in limestone rock, leafless, showing reddish white flowers and fruits, (B) leafless plant with flowers and fruits. Alain Rzepecky in Thulm et al. (2025).

The total area over which Boswellia hesperia is found is about 63 km², however, the distribution of the species is patchy, and it probably is only found over an area of about 20 km². This limited distribution, along with the apparent risk of the species being overgrazed by Goats, leads Thulm et al. to recommend that Boswellia hesperia be classified as Critically Endangered under the terms of the International Union for Conservation of Nature's Red List of Threatened Species.

Boswellia hesperia, seedling flowering after about one and a half year in cultivation. Alain Rzepecky in Thulm et al. (2025).

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Zosterophyllum baoyangense: A new species of Zosterophyllopsid Plant from the Early Devonian of Guizhou Province, China.

The first Vascular Plants appeared and underwent a dramatic radiation similar to that seem in Animals in the Cambrian, during the Late Silurian and Early Devonian. During this time both vegetative and sexual reproduction appeared, with some of the earliest Plants able to cover large areas through clonal growth, while at the same time producing spores which enabled them to distribute to new areas. During the Early Devonian structures such as leaves, roots, megaspores and secondary xylem also appeared. The Zosterophyllopsids formed a characteristic part of many Early Devonian floras, with species reported from China, North America, Europe and Australia. These Plants lacked leaves, and had a characteristic 'K'; or 'H' branching pattern, combined with lateral spike sporangia.

In a paper published in the journal Proceedings of the Royal Society B on 15 January 2025, Pu Huang of the Nanjing Institute of Geology and Palaeontology, Jia-Shu Wang of the Geological Museum of China and the Key Laboratory of Orogenic Belts and Crustal Evolution at Peking University, Yi-Ling Wang, also of the Key Laboratory of Orogenic Belts and Crustal Evolution at Peking University, Lu Liu of the National Natural History Museum of China, Jing-Yu Zhao of the School of Resources and Civil Engineering at Suzhou University, and Jin-Zhuang Xue also of the Key Laboratory of Orogenic Belts and Crustal Evolution at Peking University, describe a new species of Zosterophyllopsid Plant from the Early Devonian of Guizhou Province, China.

The new species is described upon the basis of two compression fossils from the Plant-bearing beds from the lower part of the Early Devonian Mangshan Group at Baoyang in Duyun City in Guizhou Province. These beds have been determined to be Pragian in age (410.8-407.6 million years old) on the basis of fossils which are also found in the Posongchong Formation of Yunnan Province, which in turn has been dated on the basis of spore assemblages, Plants and stratigraphic correlation It is placed in the genus Zosterophyllum, and given the specific name baoyangense, meaning 'from Baoyang'.

Zosterophyllum baoyangense  (a), (b) PB203562, part and counterpart, showing a fertile axis with K-shaped branching and a terminal spike. Arrows highlight branching points. The parts indicated by arrows (c) and (d) are enlarged in (c), (d), respectively; (c) K-shaped branching; (d) branching point showing a nearby protuberance (arrow); (e), (f) Enlarged view of the terminal spike in (a) and (b); (g) enlarged view of the basal part of the spike in (e). Arrow points to the margin of the basal sporangium. (h) Enlargement of the distal sporangia in (f) (arrow h), showing dehiscence line (white arrow) and peripheral rim along the convex distal margin (the area between two black arrows). Scale bars: (a), (b) 10 mm; (c)–(f), 1 mm; (g), (h), 0.5 mm. Huang et al. (2025).

Zosterophyllum baoyangense comprises a rhizome system with K-shaped branching and upright sporangia-bearing spikes 5.8-10.8 mm high. Each of these spikes has 5-10 sporangia, arranged in a spiral pattern. The sporangia are oval to semicircular, 1.6−2.0 mm high and 0.9−1.4 mm wide, departing from axis at an acute angle by a short stalk.

The Zosterophyllopsids are a distinctive group of Plants found worldwide from the Late Silurian to the Late Devonian. There are currently 37 described genera in the group, although it is not completely certain they form a monophyletic group. The earliest members of the group appear in the Ludlow (427.4-423.0 million years ago), with the group reaching its maximum diversity during the Pragian, then declining during the Emsian (410.62-393.47 million years ago), and eventually disappearing during the Frasnian (382.7-372.2 million years ago.

Zosterophyllum baoyangense is notably smaller that other members of same genus, with a complete specimen measuring 45.4 mm in length and 0,5-1.3 mm in width, with a spike 10.8 mm high. For comparison, the contemporary Zosterophyllum confertum from western Germany can reach 5.1 mm in width with a preserved length of 440 mm. Silurian members of the genus were typically smaller, though they grew over time, while Emsian species, while rarer, show a wider range of sizes. 

All species of Zosterophyllum lack any form of spikes, leaves, or leafy structures. However, they are presumed to have been able to photosynthesize due to the presence of stomata. With such a simple bodyplan, the only way that these plants would have been able to increase their photosynthetic surface would have been to get larger, a trend observed from their origin in the Late Silurian and through the Early Devonian. 

Zosterophyllum baoyangense, however, does not comply with this trend, being much smaller than known contemporary species, and even most Silurian specimens. Huang et al. suggest that this may be a sign of a much shorter life-cycle than other species. This in turn could be an adaptation to an unstable environment, or one with very limited resources, showing that early Vascular Plants had begun to show adaptation to different environments by the Early Devonian. 

Artist’s restoration of part of the Early Devonian Mangshan Flora, with Plant communities of Zosterophyllum baoyangense at the front, and Teyoua antrorsa, Zosterophyllum australianum and an unnamed zosterophyllopsid to the back. Huang et al. (2025).

The history of Vascular Plants can be divided into five evolutionary floras, the Rhyniophytic Flora, dominated by Rhyniophytes and Cryptospore producers, the Eophytic Flora, dominated by Zosterophyllopsids, followed by the Palaeophytic Flora,  the Mesophytic Flora and the (modern0 Cainophytic Flora. The Plants of the Rhyniophytic Flora were typically very small, and it is thought that the (first) terrestrial habitats that they inhabited were probably very ephemeral. The Plants of the Eophytic Flora, while still very simple, are generally much larger, which has been interpreted as a sign of more stable environments developing. In South China, however, a strongly seasonal wet-dry climate is known to have developed in the Early Devonian, which may have made it harder for early Plants to stabilize environments, producing dwarfed species such as Zosterophyllum baoyangense, which could have completed their entire life-cycles in a shorter period of time.

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Petalidium hoarusibense: A new species of Petal-bush from Namibia.

Petal-bushes, Petalidium spp., are woody perinal shrubs in the Family Acanthaceae found in arid sandy or stoney areas of Africa, India, and the Mascarene Islands, although most species are found in areas of Southern Africa with summer rainfall and no frosts. There are currently 32 species recognised from Namibia, 13 from Angola, and six from South Africa. Despite the name 'bush', they are diverse in form, ranging from scrambling herbs to large, robust shrubs. Many species of Petalidium are fast-growing and produce attractive  flowers, leading to some species being cultivated by gardeners.

In a paper published in the journal Phytotaxa on 8 January 2025, Wessel Swanepoel of the H.G.W.J. Schweickerdt Herbarium at the University of Pretoria, and Abraham Van Wyk, also of the H.G.W.J. Schweickerdt Herbarium at the University of Pretoria, and of the South African National Biodiversity Institute, describe a new species of Petalidium from the Kaokoveld region of northwestern Namibia.

During a visit to the Okandjombo area of the Kaokoveld in November 2023, Wessel Swanepoel obseeved a number of distinctive Petalidium Plants, with a dwarf-shrubby habit, pealing white bark, and multiple stems arrising from just below the ground level. At this  time the Plant was not in flower, making it difficult  to confirm that it was not a previously described species, however, during a follow-up visit in May 2024, the plants were found to be producing distinctive pink flowers, confirming it as a  new species. This is named Petalidium hoarusibense, in reference to the Hoarusib River, as it was discovered within the catchment of this river.

Petalidium hoarusibense. Habitat and habit. (A) Mature plant about 800 mm high (greyish shrub in foreground), growing among dark grey sedimentary rocks of the Swakop Group along the banks of the Hoarusib River near Okandjombo, Namibia. (B) Base of plant showing several branches arising from the main stem just above ground level, each covered with rough, fissured, greyish white bark. Wessel Swanepoel in Swanepoel & Vak Wyk (2025).

To date, Petalidium hoarusibense, has only been found in m the mountainous area along the Hoarusib River and its tributaries to the east and south of Okandjombo, part of the Great Escarpment of northwestern Namibia, on on arid hillsides and along drainage lines at elevations of between 450 and 700 m above sealevel. This area recieves about 100 mm of rainfall in an average year, and additionally has about five foggy days, which might contribute to the available moisture slightly..

Petalidium hoarusibense. Morphology of leaves and flowers. (A) Shoot with flower and leaves, the latter with dense, greyish white indumentum. (B), (C) Flower in front (B) and side (C) view; note bracteoles (some of spent flowers) with cobwebby indumentum. (D), (E), (F), (G) Flowers in front view, each from a different plant to show variation. Note all corolla lobes of a flower being roughly similarly coloured in various shades of magenta, or lateral and upper lobes slightly darker shaded than the anterior lobe, sometimes, as in (D), (E), & (G) with darker magenta or maroon triangular nectar guides; anterior lobe adaxially with two narrowly triangular yellow nectar guides. Wessel Swanepoel in Swanepoel & Vak Wyk (2025).

All known specimens of Petalidium hoarusibense were found growing within an area of about 20 x 18 km, although within this area there were several areas where it was quite common. There were also a large number of dead Plants on the hillsides, possibly due to a prolonged drought in the area. For this reason, Swanepoel and Van Wyk reccomend that the species be listed as Vulnerable under the terms of the International Union for the Conservation of Nature's Red List of Threatened Species.

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