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We describe Blakea ricardoi (Melastomataceae: Blakeeae), a species known only from the Parque Internacional La Amistad in Costa Rica side. It can be distinguished by the long peduncles up to 6.5 cm long, pendant flowers with green petals and indumentum of roughened trichomes. A key to other species of Blakea with pendulous flowers and connivent petals is provided.
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Pterolepis xaxa (Melastomateae, Melastomataceae), a new haplostemonous species from Bahia, Brazil
We describe Pterolepis xaxa (Melastomateae, Melastomataceae), a new species collected in “caatinga rupestre” at Licínio de Almeida, Bahia, Brazil. Pterolepis xaxa resembles the recently described Pterolepis haplostemona, both representing the only two species in the genus that are haplostemonous (i.e., with the stamens equal in number to the petals). Apart from flowers with a single whorl of stamens, P. xaxa can also be recognized by intercalycine projections consisting of a very short central axis topped with 2–3 trichomes, and white petals (vs. intercalycine projections lacking trichomes at the apex and magenta or lilac petals in P. haplostemona).
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- PAR ID:
- 10437440
- Date Published:
- Journal Name:
- Brittonia
- ISSN:
- 0007-196X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Pseudoernestia (Melastomataceae: Marcetieae) is a genus comprising two species, P. cordifolia and P. glandulosa, with disjunct distributions along the Amazon Rainforest. The genus is characterized by narrow sepals, petals bearing an apical glandular trichome, antesepalous stamens with aristate ventral appendages and calcarate dorsal appendages positioned opposite the ventral ones, a glabrous ovary with three locules, rarely two, and seeds lacking dorsolateral projections. We present a taxonomic review of Pseudoernestia, including a lectotypification for P. cordifolia, the type species of the genus. Based on herbarium data, we confirmed that P. cordifolia occurs in Venezuela and Brazil, typically on rocky outcrops, whereas P. glandulosa is found in French Guiana and Guyana, primarily on lateritic soils. Pseudoernestia cordifolia is categorized as Endangered, while P. glandulosa is assessed as Least Concern. We provide detailed descriptions, photographs of living specimens, scanning electron microscopy images of the seeds, geographic distribution maps, and notes on conservation status, habitat preferences, and phenology.more » « less
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Recent field research on the eastern slopes of the Andes resulted in the discovery of a new species ofBomareafrom the Cerro Candelaria Reserve in the Tungurahua province of Ecuador.Bomarea pastazensisis the second smallest species in the genus and differs from the smallest by the presence of glutinous trichomes on the ovary, glabrous sepals, and greenish-yellow petals with purple spots. Based on IUCN guidelines, a preliminary conservation status is assigned as Vulnerable (VU).more » « less
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Miconia tetrandra, a morphologically distinctive species restricted to the Caribbean region, is provided with an updated assessment of its phylogenetic position and taxonomy. A detailed description and nomenclatural treatment are provided, along with a consideration of phenology, distribution and habitat, and citation of specimens examined. The species is a member of the Caribbean clade, and it is unusual within Miconia in having flowers with only four stamens (alternating with the petals), with short, obovate, yellow anthers that each open by two large pores. Miconia tetrandra is morphologically quite divergent from, but is likely related to, a clade comprised by M. angustifolia, M. urbanii, and M. biflora, and these three species traditionally have been included within the genus Tetrazygia. In contrast, M. tetrandra usually has been placed within Miconia.more » « less
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Traits conserved across evolutionary time often provide compelling examples of key adaptations for a given taxonomic group. Tetradynamy is the presence of four long stamens plus two short stamens within a flower and is conserved across most of the roughly 4000 species in the mustard family, Brassicaceae. While this differentiation in stamens is hypothesized to play a role in pollination efficiency, very little is known about the potential function of the two stamen types. The present study sheds new light on this mystery using wild radish (Raphanus raphanistrum), a widespread and well-studied tetradynamous plant. We used data collected from slow-motion videos of pollinators visiting wild radish flowers to test three adaptive hypotheses (not mutually exclusive): (H1) short and long stamens are specialized for either feeding or pollinating; (H2) short and long stamens are specialized for different pollinator taxa; and (H3) the presence of short and long stamens increases pollinator movement and thus effectiveness. We find evidence consistent with hypothesis H3, but no evidence for hypotheses H1 or H2. Thus, tetradynamy may be an adaptation for generalized pollination, enabling effective visits by the variety of pollinators visiting most species of Brassicaceae.more » « less
- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1007/s12228-023-09747-x
