Pedunculate Inflorescences Research Articles

New insight in secretory structures and secretion composition in Rhus typhina L. – Anatomical, histochemical, and ultrastructural studies

Rhus typhina is a valuable plant used in the pharmaceutical, cosmetic, and food industries due to the presence of biologically active substances accumulated in its organs, especially in secretory structures, i.e. trichomes and secretory ducts. Light microscopy, scanning electron microscopy, and transmission electron microscopy were used to examine the structure of glandular and non-glandular trichomes, as well as secretory ducts present in inflorescence peduncles of R. typhina. The chemical composition of the secretion produced by trichomes and ducts was assessed using histochemical techniques, including observations under brightfield and fluorescence microscopes. Two types of capitate glandular trichomes producing secretions with a similar composition and non-glandular trichomes exhibiting secretory activity were identified. The secretion of glandular trichomes was dominated by acidic and neutral lipids, essential oil, sesquiterpenes, and steroid-containing terpenes. The schizogenic secretory ducts located in the phloem produced a viscous milky substance with acidic polysaccharides, acidic lipids, phenolic compounds, and proteins. The secretion was released into the duct lumen through notches in the walls of the secretory epithelial cell facing the duct lumen. The location, type, and traits of the non-glandular trichomes and secretory structures, as well as the composition of the secreted products are considered important taxonomic features in the family Anacardiaceae and the Rhus genus. Additionally, these characters are important diagnostic markers for the pharmacobotanical identification of the species in medicinal and cosmetic raw materials. The various compounds present in the secretory structures of R. typhina may contribute to plant protection against pathogens or herbivory and probably play a role as attractants for pollinators and seed dispersers.

Hedyotislongiramulis (Rubiaceae), a new species from south China.

Hedyotislongiramulissp. nov. (Rubiaceae) is described from Guangdong Province, China. It is similar to H.caudatifolia but differs in having puberulent, more or less tetragonal and decussately sulcate juvenile stems, waxy leaf surface, short inflorescence peduncles, high length ratio of corolla lobe to tube, and subglobose capsules. The phylogenetic analysis reveals that H.longiramulis is sister to H.pubirachis. Dimorphism concerning pollen size was observed in the heterostylous flowers. The complete chloroplast genome of the new species comprises a typical quadripartite structure of 153,616 bp in length, with two inverted repeats of 25,457 bp, a large single-copy of 85,050 bp and a small single-copy of 17,652 bp. It contains 112 unique genes, including 79 protein-coding genes, 29 tRNA genes, and four rRNA genes, the GC content of the chloroplast genome is 32.4%. The new species is provisionally evaluated as "Least Concern" because it is common and well-protected in two Provincial Nature Reserves.

An unusual plane tree from the Early Cretaceous of Kansas, USA

We present a new genus and species of platanaceous inflorescences from the Hoisington III locality of Barton County, Kansas, USA. This locality lies within the Albian Dakota Formation, which was formed from deposits along the eastern margin of the mid-Cretaceous North American Western Interior Seaway. The elongate inflorescences documented here are unusual for Platanaceae, which is known for its globose, unisexual inflorescences. Distefananthus hoisingtonensis Huegele and Wang gen. et sp. nov. has elongate, cylindrical, ellipsoid, pedunculate inflorescences bearing apocarpous achenes with long styles, borne in florets of 3-4, with over 100 fruits per inflorescence, and stamens with short filaments and hairy apical connectives. The small and relatively fixed number of parts per floret ((3-)4 fruits and c. 3-4 stamens) is seen in other Cretaceous Platanaceae inflorescences and may have facilitated insect pollination. The state of perianth development is unclear, and the fruits lack basal dispersal hairs. The Hoisington material encompasses a developmental sequence; younger inflorescences bear a mix of stamens and immature carpels (thin with long styles) while mature inflorescences bear developed fruits (thicker and often with broken styles) and have lost all stamens. Like the typical globose capitula, the elongate inflorescences probably originated from the reduction of a compound inflorescence. The elongate inflorescences may represent a less compressed, ancestral or pleisiomorphic condition for Platanaceae. The only other species from this family known for elongate inflorescences is from the Paleocene and Eocene of western North America. The inflorescences from Hoisington co-occur with Sapindopsis leaves. At this locality, Sapindopsis powelliana occurs at a similar frequency to the elongate inflorescences and is a possible candidate for the leaves associated with them. The Hoisington material marks the earliest known occurrence of bisexual inflorescences in Platanaceae. The discovery of Distefananthus hoisingtonensis offers new insight into the diversity of platanaceous inflorescences in the mid-Cretaceous, a critical early period in the history of Platanaceae.

Cyrtandra villosissima var. flavovirens (Gesneriaceae), a new variety from Zamboanga Del Norte, Philippines

A new variety of Cyrtandra villosissima from Zamboanga del Norte, Philippines, C. villosissima var. flavovirens, is here described. Both C. villosissima var. villosissima and C. villosissima var. flavovirens are erect suffrutescent plants, with large leaves that are slightly falcate, and have inflorescences with linear, densely hirsute bracts. Cyrtandra villosissima var. flavovirens can be distinguished from C. villosissima var. villosissima by its pale yellow to yellow-green corollas and its pedunculate inflorescences. A key to morphologically similar taxa, distribution maps, and photographs of the varieties are here provided.

Rudgea infundibuliformis (Palicoureeae, Rubiaceae), a new species from Southeastern Brazil

A new species of Rudgea (Rubiaceae) was discovered in a forest remnant in the state of Rio de Janeiro, Brazil, within the Atlantic Rainforest, and is distinguished by its relatively small leaves, reduced inflorescences, and the broadly infundibular, externally densely tomentose corolla. Rudgea infundibuliformis is categorized as Critically Endangered, and is known so far from a single locality, the “Mata do Quimbira”, in the municipality of Italva. This rare species is probably related to other species of the Jasminoides informal Group, sharing characters as the leaf blade with axillary domatia in the secondary veins beneath, terminal and pedunculate inflorescences, lobed calyx, infundibular corolla, and ripe fruits orange or red.

A new species of Casearia Jacq. from Brazil

Abstract A new species of Salicaceae growing in the state of Espírito Santo and in the south of the state of Bahia, Casearia valenciana R.Marquete & R.B.Torres, is described and illustrated here. It is similar to C. cotticensis Uittien, which grows further north in Amazonian Forest, by its pedunculate inflorescence, coriaceous leaves, and glabrous ovary. Yet, it differs from C. cotticensis by its shrub to small tree habit (vs. tree up to 27 m tall), smaller stipules, elliptic leaves (vs. lanceolate, broadly lanceolate, oblong-lanceolate), elongated anthers with longitudinal slits (vs. slightly deltoid, transversal slits), and larger fruits and seeds. Other diagnostic features of this new species include short-serrulate leaf border, and disc lobes fused with filaments at the base forming a small tube.

Why is phloem sap nitrate kept low?

Since the first description of phloem sap composition nearly 60 years ago, it is generally assumed that phloem sap does not contain nitrate and that there is little or no backflow of nitrate from shoots to roots. While it is true that nitrate can occasionally be absent from phloem sap, there is now substantial evidence that phloem can carry nitrate and furthermore, transporters involved in nitrate redistribution to shoot sink organs and roots have been found. This raises the question of why nitrate may or may not be present in phloem sap, why its concentration is generally kept low, and whether plant shoot-root nutrient cycling also involves nitrate. We propose here that phloem sap nitrate is not only an essential component of plant nutritional signaling but also contributes to physical properties of phloem sap and as such, its concentration must be controlled to ensure proper coordination of plant development and nutrient transport. This article is protected by copyright. All rights reserved.

<p><strong>A new species of <em>Oryctanthus</em> (Loranthaceae) from Colombia</strong></p>

A new species of the hemiparasitic genus Oryctanthus from Colombia is described and illustrated. This species is known only from two nearby localities and it can be distinguished from similar species by its terete stems being grayish at maturity, coriaceous leaves with secondary inconspicuous venation and completely furfuraceous inflorescence peduncles, which are 3 or 4 times longer than the fertile portion of the inflorescence. Taxonomic affinities of this species and its conservation status are also discussed.

<p><strong>One new Mexican <em>Salacia</em></strong><em> </em><strong>with pedunculate inflorescences</strong><em> </em><strong>(Celastraceae, Salacioideae)</strong></p>

One new species of Salacia (Celastraceae, Salacioideae) with pedunculate inflorescences from Puebla, Mexico, is described: S. pueblana Lombardi. It is distinguished by its flat, canaliculate disc, papillose sepals, and flowers that dry yellowish-green. It resembles S. multiflora (Lam.) DC. subsp. multiflora by its slender branched inflorescence, but differs from it by its flower outline, disc, and sepals.

Revision of the Madagascan endemic Homollea (Rubiaceae - Pavetteae), with description of two new species

Homollea Arènes (Rubiaceae, subfamily Ixoroideae, tribe Pavetteae) is a genus of shrubs and small trees endemic to western and northern Madagascar. The genus comprises five species occurring in dry deciduous forest, often in limestone areas. The five species are narrow endemics and their conservation status is either Endangered (4 species) or Critically Endangered (1 species). Homollea is characterized by few-flowered, pseudo-axillary, pedunculate inflorescences, well-developed calyces with the lobes much longer than the tube, laterally flattened seeds with a shallow, elongated to linear hilum and entire endosperm, ovules arising from the upper margin of the placenta, and, pollen grains with supratectal elements in the shape of microgemmae. Until now, three species were known and their descriptions are amended. Two further species, H. furtiva De Block sp. nov. and H. septentrionalis De Block sp. nov., are described as new for science. The five species are dealt with in detail: descriptions, distribution maps, conservation assessments, illustrations, lists of exsiccatae and an identification key are given.

La circunscripsión de Palicourea subgen. Heteropsychotria (Rubiaceae Palicoureeae)

The subgenus Heteropsychotria was detected and described by Julian Steyermark in the frame of the monographic series of the Botany of the Guyana Highland (Steyermark 1972) and repeatedly in a more illustrated version in the Flora of Venezuela (Steyermark 1974). Within the subgenus he distinguished 13 sections and 31 series. Three sections (Nrs 4, 7 and 11) of the 13 remained without names and descriptions. After the fundamental molecular taxonomic study of Nepokroeff et al. (1999) a publishing activity started producing a number of critical studies separating some sections as valid individual genera. The section Chytropsia has been included into the genus Margaritopsis Ch. Wright (Andersson 2001, Taylor 2005). The section Notopleura regained its generic status according to Bremekamp’s original concept (Taylor 2001). The Mapouria section has been eliminated by the re-establishment of the Carapichea genus (Andersson 2002b, Taylor and Gereau 2013). It has been recently recognised, that the greater part of th...

Two New Anisophyllous Species of Sabicea Aubl. (Rubiaceae) from Gabon

LACHENAUD, O. & L. ZEMAGHO (2015). Two new anisophyllous species of Sabicea Aubl. (Rubiaceae) from Gabon. Candollea 70: 219-229. In English, English and French abstracts. DOI: http://dx.doi.org/10.15553/c2015v702a7 Two new Rubiaceae species, Sabicea golgothae O. Lachenaud & Zemagho and Sabicea mabouniensis O. Lachenaud & Zemagho, are described and illustrated. These two species are very similar to each other, and differ from all their congeners by the combination of strong anisophylly and pedunculate inflorescences. Their position in the genus is discussed. Both species are apparently endemic to the Mabounie area in West-Central Gabon, currently under exploitation prospects for mining. They are both assessed as “Critically Endangered” according to IUCN Categories and Criteria.

A New Species ofDendropanax(Araliaceae) of Restricted Range from the Caribbean Slope of Panama

Dendropanax pachypedunculatus Idarraga & Lowry (Araliaceae) is described from lowland forest in the Donoso District of Colon Province along the Caribbean slope of Panama. It most closely resembles D. arboreus (L.) Decne. & Planch., from which it can be distinguished by several characters including its larger fruits, thicker primary inflorescence axes and peduncles, and leaves with pinnate (vs. mostly triplinerved) venation. This new species is known from a single collection made within the footprint of a copper mining project. A preliminary risk of extinction assessment using the IUCN Red List categories and criteria indicates that D. pachypedunculatus should be considered Critically Endangered (CR).

Amphithalea ornata (Podalyrieae, Fabaceae), a rare new species from the Western Cape Province, South Africa

The new species, Amphithalea ornata, from the Worcester Valley in the Western Cape Province of South Africa, forms part of a group of four species with pedunculate inflorescences. Among these species it is most similar to Amphithalea spinosa but differs in its non-spinescent habit, shorter peduncles, and large, imbricate calyx lobes. A. ornata is restricted to the Breede River Valley where it occurs in Breede Shale Renosterveld at the southern foot of the Droëriviersberg, south of Worcester.

Reldia longipedunculata (Gesneriaceae), a new species from the Mache-Chindul Mountains of Northwestern Ecuador and an updated checklist of Reldia for the Neotropics

A new species, Reldia longipedunculata (Gesneriaceae, tribe Beslerieae), is described from the Mache-Chindul Mountains near the border of the Bilsa Biological Research Station in northwestern Ecuador (province of Esmeraldas). The new species differs from all other species of Reldia by the presence of erect peduncles to 10 cm long and narrowly obovate leaves. An updated checklist and key are provided for the seven currently recognized species of Reldia. A previous infraspecific variety is recognized at the species rank as Reldia veraguensis. The presence of pedunculate inflorescences is discussed as a common character in five of the seven species of Reldia.

A new species of Chalybea (Blakeeae, Melastomataceae) from the Ecuador-Peru border

A new species, Chalybea brevipedunculata, from the Ecuador-Peru border is herein described and illustrated. It differs from all other species in the genus by having inflorescence peduncles that are shorter than their subtending leaf petioles.

A new species of Standleya (Rubiaceae, Coussareeae) with a new record for Bahia, Brazil

Standleya glomerulata, a new species and a first record for the semiarid region of Bahia, Brazil, is described and illustrated. It differs from all other known species of the genus by its prostrate decumbent and reptant habit, glomerulate sessile inflorescences, and a calyx with two unequal lobes. S. prostrata has a similar habit, but can be distinguished by the pedunculate inflorescences and a calyx with four equal lobes. The new species is known from only a few localities in two protected areas and must therefore be considered threatened.

A new species of Tragia (Euphorbiaceae) from Oaxaca, Mexico

A new species of Tragia from the state of Oaxaca, Mexico is described and illustrated; it is different from other known Mexican species, although somewhat similar in habit to T. nepetifolia. Tragia chiltepeca is an erect herb with deeply cordate leaves with an acuminate apex and a long petiole, a long pedunculate inflorescence, a single pistillate flower in the proximal node, several male flowers at the distal nodes, and pyriform buds. This species is endemic to the Tuxtepec district. A taxonomic key is provided to distinguish this from other Tragia species in Oaxaca.

<p><strong>A new species of <em>Tragia</em> (Euphorbiaceae) from Oaxaca, Mexico</strong></p>

A new species of Tragia from the state of Oaxaca, Mexico is described and illustrated; it is different from other known Mexican species, although somewhat similar in habit to T. nepetifolia. Tragia chiltepeca is an erect herb with deeply cordate leaves with an acuminate apex and a long petiole, a long pedunculate inflorescence, a single pistillate flower in the proximal node, several male flowers at the distal nodes, and pyriform buds. This species is endemic to the Tuxtepec district. A taxonomic key is provided to distinguish this from other Tragia species in Oaxaca.

Miconia indicoviolacea (Melastomataceae: Miconieae): a new Colombian species from the western flanks of the cordillera Occidental

Miconia indicoviolacea is described from the western slopes of the western cordillera in the Chocó biogeographic region of Colombia, illustrated, and compared with superficially similar species that are also endemic to the country. It is readily recognized by its prevailingly purple to dark blue inflorescence branches, peduncles, and internodes, minute glandular-puberulent vegetative and hypanthial indumentum, caudate foliar apex, dorsally inclined anther pores, glabrous rounded to truncate dorso-basal staminal appendages, and seeds with a conspicuous appendage at the chalazal end and a raphal zone that is approximately double the size of the seed corpus.