Tetraplasandra lydgatei (Araliaceae): Taxonomic Recognition of a Rare, Endemic Species from O'ahu, Hawaiian Islands

Tetraplasandra is a genus of seven species endemic to the Hawaiian Archipelago. Recent field studies in the Ko'olau Mountains on the island of O'ahu have led to a taxonomic reevaluation of a rare species, Tetraplasandra lydgatei. The species, originally described in the late 1800s, was placed into the widespread, polymorphic species T. oahuensis in a subsequent treatment of the genus. Several morphological characters and varying ecological habitats distinguish the two species. Based on these differences T. lydgatei deserves formal taxonomic recognition. Furthermore, T. lydgatei was an uncommon species even when it was originally described. This may be due to the early human alteration of the dry and mesic Hawaiian forests for housing and agriculture and also that the species was always only an occasional component of the mesic ecosystem. Regardless of the reasons, the rarity of this species has been accelerated. Currently, only six individuals of T. lydgatei are known to exist, and conservation efforts to protect it are needed

Utility of RAPD Markers in Evaluating the Status of the Hawaiian Tree Fern Cibotium x heleniae

Randomly amplified polymorphic DNA (RAPD) markers provide data consistent with the conclusion based on morphological characters that the recently named taxon Cibotium xheleniae is indeed of hybrid origin. This assertion is supported by (I) placement of C. xheleniae intermediate to the parent taxa, as determined by genetic similarity data; (2) location of C. xheleniae individuals on a clade intermediate to the parent species in the cladistic analysis; and (3) clustering of the C. xheleniae individuals between clusters of parental individuals in principal components analysis. Additivity of parental genetic markers in the putative hybrid ranged from 54 to 64%, providing additional though modest support for the hypothesized origin of C. x heleniae. Our results indicate that RAPD data can be of considerable value in assessing potential hybridity of individuals in naturally occurring populations

Molecular Phylogenetics of Alternanthera (Gomphrenoideae, Amaranthaceae): Resolving a Complex Taxonomic History Caused by Different Interpretations of Morphological Characters in a Lineage with C4 and C3-C4 Intermediate Species

Aternanthera (Amaranthaceae) is a diverse genus (80-200 species) largely restricted to the American Tropics. With Pedersenia and Tidestromia, it makes up the Alternantheroid clade in Gomphrenoideae. Parsimony and Bayesian analyses of nucleotide sequences of nuclear (ITS) and plastid (rpl16, trnL-F) and morphological characters identify that the capitate stigma of Alternanthera is a synapomorpy within the Alternantheroids. Within Alternanthera, two major clades were resolved, both of which were marked by otherwise homoplasious characters of the gynoecium: Clade A [99% jackknife (JK); 1.0 posterior probability (PP)] with nine species and Clade B (60% JK; 0.98 PP) with 22 species. Four subclades (B1B4), strongly supported statistically, were identified in Clade B. Previous subgeneric classifications of Alternanthera appear artificial in light of our new molecular phylogenetic analyses. Most major lineages are congruently resolved by nuclear and plastid data but some incongruence between the nrITS and plastid phylogenetic trees suggests hybridization may have played a role in the rampant speciation in Alternanthera. Whereas C4 photosynthesis appears to have evolved in a single clade, the position of A. littoralis var. maritima (C3) in this clade may be explained by hybrid speciation rather than a reversal from C4 to C3. All C3-C4 intermediates belong to a different clade that also contains C3 species, but species limits, including the widely studied A. tenella, are unclear. The clade including A. tenella and A. halimifolia contains most of the species endemic to the Galápagos whereas A. nesiotes, also endemic to the islands, is nested among widespread American taxa. This suggests that the Galápagos radiation of Alternanthera may have arisen from at least two independent colonization events followed by a subsequent radiation in the former lineage. © 2012 The Linnean Society of London

Anther Appendages of Incarvillea Trigger a Pollen-Dispensing Mechanism

Background and Aims Anther appendages play diverse roles in anther dehiscence and pollen dispersal. This study aims to explore the pollen-dispensing mechanism triggered by special anther appendages in Incarvillea arguta. Methods Field studies were conducted to record floral characteristics, pollinator visitations, and flower-pollinator interactions. Measurements of flowers and pollinators were analysed statistically. Pollen counts following a series of floral manipulations were used to evaluate pollen dispensing efficiency and function of the anther appendages. Key Results Field observations determined that two species of Bombus (bumble-bees) were the primary pollinators of I. arguta with a mean visiting frequency of 1.42 visitations per flower h-1. The results display a diminishing pollen dispensing pattern; the proportion of remaining pollen removed by pollinators decreased from 27 % to 10 % and 7 % in subsequent visits. Anther appendages act as a trigger mechanism to dispense pollen. The arrangement of the anthers and appendages function to control pollen load and timing. Mechanical stimulation experiments revealed that one set of appendages is only triggered by stimulation in the direction moving into the flower, while the other set is only triggered by stimulation in the opposite direction (exiting the flower). Conclusions The anther appendage is a pollen-dispensing trigger mechanism. The configuration of the stamens and duel trigger system has evolved to allocate pollen in allotments to enhance male function

Systematic Revision of Elaphoglossum (Dryopteridaceae) in French Polynesia, with the Description of Three New Species

Species descriptions and a key for the nine species of Elaphoglossum (Dryopteridaceae) in French Polynesia are provided. Three new species are described: E. austromarquesense from the southern Marquesas Islands, E. florencei from Raiatea and Moorea, and E. meyeri from Rapa. Each species is illustrated by a line drawing of the habit, and spore images using a scanning electron microscope. Images of scales, one of the most important diagnostic characters in the genus, are also included. © 2008 The Linnean Society of London

Anther Appendages of Incarvillea Trigger a Pollen-dispensing Mechanism

† Background and Aims Anther appendages play diverse roles in anther dehiscence and pollen dispersal. This study aims to explore the pollen-dispensing mechanism triggered by special anther appendages in Incarvillea arguta. † Methods Field studies were conducted to record floral characteristics, pollinator visitations, and flower -pollinator interactions. Measurements of flowers and pollinators were analysed statistically. Pollen counts following a series of floral manipulations were used to evaluate pollen dispensing efficiency and function of the anther appendages. † Key Results Field observations determined that two species of Bombus (bumble-bees) were the primary pollinators of I. arguta with a mean visiting frequency of 1 . 42 visitations per flower h 21 . The results display a diminishing pollen dispensing pattern; the proportion of remaining pollen removed by pollinators decreased from 27 % to 10 % and 7 % in subsequent visits. Anther appendages act as a trigger mechanism to dispense pollen. The arrangement of the anthers and appendages function to control pollen load and timing. Mechanical stimulation experiments revealed that one set of appendages is only triggered by stimulation in the direction moving into the flower, while the other set is only triggered by stimulation in the opposite direction (exiting the flower). † Conclusions The anther appendage is a pollen-dispensing trigger mechanism. The configuration of the stamens and duel trigger system has evolved to allocate pollen in allotments to enhance male function

In Vitro Pharmacological Characterization of RXFP3 Allosterism: An Example of Probe Dependency

Recent findings suggest that the relaxin-3 neural network may represent a new ascending arousal pathway able to modulate a range of neural circuits including those affecting circadian rhythm and sleep/wake states, spatial and emotional memory, motivation and reward, the response to stress, and feeding and metabolism. Therefore, the relaxin-3 receptor (RXFP3) is a potential therapeutic target for the treatment of various CNS diseases. Here we describe a novel selective RXFP3 receptor positive allosteric modulator (PAM), 3-[3,5-Bis(trifluoromethyl)phenyl]-1-(3,4-dichlorobenzyl)-1-[2-(5-methoxy-1H-indol-3-yl)ethyl]urea (135PAM1). Calcium mobilization and cAMP accumulation assays in cell lines expressing the cloned human RXFP3 receptor show the compound does not directly activate RXFP3 receptor but increases functional responses to amidated relaxin-3 or R3/I5, a chimera of the INSL5 A chain and the Relaxin-3 B chain. 135PAM1 increases calcium mobilization in the presence of relaxin-3NH2 and R3/I5NH2 with pEC50 values of 6.54 (6.46 to 6.64) and 6.07 (5.94 to 6.20), respectively. In the cAMP accumulation assay, 135PAM1 inhibits the CRE response to forskolin with a pIC50 of 6.12 (5.98 to 6.27) in the presence of a probe (10 nM) concentration of relaxin-3NH2. 135PAM1 does not compete for binding with the orthosteric radioligand, [125I] R3I5 (amide), in membranes prepared from cells expressing the cloned human RXFP3 receptor. 135PAM1 is selective for RXFP3 over RXFP4, which also responds to relaxin-3. However, when using the free acid (native) form of relaxin-3 or R3/I5, 135PAM1 doesn't activate RXFP3 indicating that the compound's effect is probe dependent. Thus one can exchange the entire A-chain of the probe peptide while retaining PAM activity, but the state of the probe's c-terminus is crucial to allosteric activity of the PAM. These data demonstrate the existence of an allosteric site for modulation of this GPCR as well as the subtlety of changes in probe molecules that can affect allosteric modulation of RXFP3

Rediscovery of Labordia triflora (Loganiaceae)

Labordia triflora Hillebr. is resurrected as a species distinct from L. tinifolia A. Gray based on its rediscovery on the island of Moloka'i in the Hawaiian Islands. It differs from L. tinifolia in its scandent habit, cordate leaf base, shorter petioles, slightly larger flowers and fruits, and fewer flowers per inflorescence on pistillate plants. Labordia triflora is endemic to Moloka'i, whereas L. tinifolia occurs on all major islands in the archipelago. The two taxa maintain allopatric populations on Moloka'i that are isolated by the physical and spatial barriers of a mountain range. Distinct morphology and allopatric distributions of the two taxa support resurrection of L. triflora as a separate species

Development of a DNA Library for Native Hawaiian Plants

The native Hawaiian flora is under severe stress because of habitat loss and effects of invasive plants and animals introduced into the ecosystem. These factors are threatening to push many of the endemic species to extinction. In an effort to provide a broad genetic base from which research projects on native species may be initiated, DNA was isolated from endemic and indigenous species from Hawai'i, Kaua'i, Uina'i, Maui, Moloka'i, and O'ahu and included in a newly created Native Hawaiian Plants DNA Library. DNA accession numbers and collection information are presented for 206 species representing 75 families and 128 genera