The floral development of Neurada procumbens L. (Neuradaceae)

FWN – Publicaties zonder aanstelling Universiteit Leide

Are the genera Hallea and mitragyna (Rubiaceae-coptosapelteae) pollen morpholically distinct?

FWN – Publicaties zonder aanstelling Universiteit Leide

Are the genera Hallea and mitragyna (Rubiaceae-coptosapelteae) pollen morpholically distinct?

FWN – Publicaties zonder aanstelling Universiteit Leide

Older Cancer Patients’ User Experiences With Web-Based Health Information Tools:A Think Aloud Study

Background: Health information is increasingly presented on the Internet. Several Web design guidelines for older Web users have been proposed; however, these guidelines are often not applied in website development. Furthermore, although we know that older individuals use the Internet to search for health information, we lack knowledge on how they use and evaluate Web-based health information. Objective: This study evaluates user experiences with existing Web-based health information tools among older (≥ 65 years) cancer patients and survivors and their partners. The aim was to gain insight into usability issues and the perceived usefulness of cancer-related Web-based health information tools. Methods: We conducted video-recorded think-aloud observations for 7 Web-based health information tools, specifically 3 websites providing cancer-related information, 3 Web-based question prompt lists (QPLs), and 1 values clarification tool, with colorectal cancer patients or survivors (n=15) and their partners (n=8) (median age: 73; interquartile range 70-79). Participants were asked to think aloud while performing search, evaluation, and application tasks using the Web-based health information tools. Results: Overall, participants perceived Web-based health information tools as highly useful and indicated a willingness to use such tools. However, they experienced problems in terms of usability and perceived usefulness due to difficulties in using navigational elements, shortcomings in the layout, a lack of instructions on how to use the tools, difficulties with comprehensibility, and a large amount of variety in terms of the preferred amount of information. Although participants frequently commented that it was easy for them to find requested information, we observed that the large majority of the participants were not able to find it. Conclusions: Overall, older cancer patients appreciate and are able to use cancer information websites. However, this study shows the importance of maintaining awareness of age-related problems such as cognitive and functional decline and navigation difficulties with this target group in mind. The results of this study can be used to design usable and useful Web-based health information tools for older (cancer) patients

Comparative wood anatomy and origin of woodiness in subfamilies Secamonoideae and Asclepiadoideae (Apocynaceae)

The Apocynaceae subfamilies Secamonoideae and Asclepiadoideae have undergone several transitions during their evolution with regard to growth form and degree of woodiness. In this study, we present a wood anatomical overview of both subfamilies that complements previous work on the remaining Apocynaceae. Detailed microscopic wood descriptions using light and scanning electron microscopy were performed on 60 species that cover most Secamonoideae genera and all major woody Asclepiadoideae lineages. Our observations are in line with subfamilial and (sometimes sub)tribal delimitations. Furthermore, we present for the first time an overview of the estimated number of shifts from herbaceousness to (phylogenetically) derived woodiness in Asclepiadoideae, along with a derived woody species list with distribution and habitat information. In total, at least 168 derived woody species resulting from at least 28 independent woodiness transitions were found, with drought possibly being one of the main drivers of most of these transitions.NaturalisPlant science

Description of 11 new Astiella (Spermacoceae, Rubiaceae) species endemic to Madagascar

Astiella is an herbaceous genus endemic to Madagascar, originally described with a single species A. delicatula Jovet. Molecular and morphological evidence place it in the tribe Spermacoceae s. lat. of Rubiaceae. During herbarium studies and fieldwork in Madagascar, 11 new Astiella species were identified and these are described here: A. antongilensis Groeninckx sp. nov., A. antsalovansis Groeninckx sp. nov., A. confusa Groeninckx sp. nov., A. deblockiae Groeninckx sp. nov., A. desseinii Groeninckx sp. nov., A. homolleae Groeninckx sp. nov., A. latifolia Groeninckx sp. nov., A. longifimbria Groeninckx sp. nov., A. perrieri Groeninckx sp. nov., A. pulla Groeninckx sp. nov., and A. tsaratanensis Groeninckx sp. nov. The genus Astiella now holds 12 species in total that are all endemic to Madagascar.Plant science

Variation in xylem structure from tropics to tundra: Evidence from vestured pits

Bordered pits play an important role in permitting water flow among adjacent tracheary elements in flowering plants. Variation in the bordered pit structure is suggested to be adaptive in optimally balancing the conflict between hydraulic efficiency (conductivity) and safety from air entry at the pit membrane (air seeding). The possible function of vestured pits, which are bordered pits with protuberances from the secondary cell wall of the pit chamber, could be increased hydraulic resistance or minimized vulnerability to air seeding. These functional hypotheses have to be harmonized with the notion that the vestured or nonvestured nature of pits contains strong phylogenetic signals (i.e., often characterize large species-rich clades with broad ecological ranges). A literature survey of 11,843 species covering 6,428 genera from diverse climates indicates that the incidence of vestured pits considerably decreases from tropics to tundra. The highest frequencies of vestured pits occur in deserts and tropical seasonal woodlands. Moreover, a distinctly developed network of branched vestures is mainly restricted to warm habitats in both mesic and dry (sub)tropical lowlands, whereas vestures in woody plants from cold and boreal arctic environments are usually minute and simple. A similar survey of the frequency of exclusively scalariform perforation plates illustrates that the major ecological trend of this feature is opposite that of vestured pits. These findings provide previously undescribed insights suggesting that vessels with vestured pits and simple perforation plates function as an efficient hydraulic system in plants growing in warm environments with periodical or continuous drought stress. NaturalisPlant science

Comparative wood anatomy of the blueberry tribe (Vaccinieae, Ericaceae s.l)

Wood samples of 111 Vaccinieae specimens (Vaccinioideae, Ericaceae s.l.) representing 98 species and 26 genera are investigated with light microscopy and scanning electron microscopy. The wood structure of Vaccinieae delivers taxonomically important characters that can be used to define some subclades within the tribe. The wood of the large polyphyletic genus Vaccinium strongly resembles non-vaccinioid members of the family, which are characterized by bordered vessel-ray pits and relatively narrow (2- to 4-seriate) and low multiseriate rays (often less than 1000 m) with exclusively or mainly procumbent body ray cells. The East Malesian clade, Meso-American/Caribbean clade, and the Andean clade show a combination of wood anatomical features that is lacking in other representatives of the family. These features include scalariform vessel-ray pits with strongly reduced borders, a high portion of upright body ray cells, wide (4- to 14-seriate) and high multiseriate rays (often more than 3000 m), and prismatic crystals in chambered ray cells (although absent in Symphysia racemosa). The presence of secretory ducts in the primary xylem and in the pith tissue may represent a synapomorphy for the Andean clade. Furthermore, the presence of undivided axial parenchyma cells, usually ranging from 500 to 900 m, seems to be unique in the subfamily.  FWN – Publicaties zonder aanstelling Universiteit Leide