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New Phytologist Meeting Report for the 10th International Conference on Mycorrhiza (ICOM10), Mérida, Mexico, June 30 – July 5 2019

This study investigates how anatomical characters can be used to differentiate two morphologically close species, Melanohalea olivacea (L.) O. Blanco et al. and M. septentrionalis (Lynge) O. Blanco et al. Although the two species are morphologically differentiated, mainly based on the position and shape of pseudocyphellae on the lobes, poorly-developed specimens can be difficult to identify based on morphology alone. For example, in Switzerland, both species are at the south-west limit of their distribution range and most specimens are small and not fully developed. In such cases, anatomical characters are particularly useful in separating the two species. Five anatomical characters were studied: spore length and width; hymenium, subhymenium and hypothecium height. A nested ANOVA showed that variation of spore length was 155 times greater between species than between individuals of the same species, itself 5 times higher than within individuals. In a Principal Component Analysis, despite a substantial variation of the anatomical characters within both species, a significant species differentiation appeared distinctly on the first axis (P < 0·001), which accounted for 62·35% of the total variance, and the type specimens nested within each species. Finally, a Discriminant Linear Analysis assigned 100% of the individuals to their species class, the best predictors to discriminate between the two species being subhymenium height and spore length. These characters proved to be powerful in identifying specimens with a poorly-developed morphology and confirmed the presence of M. olivacea in Switzerland

In tropical South America (Venezuela, Colombia, Ecuador, Peru, Bolivia and Brazil), we investigated the diversity of Usnea species with a pigmented, C+ yellow medulla. Four species are treated: the sorediate U. ceratina and U. entoviolata, the latter being new for South America, and the non-sorediate U. cristatula and U. flavorubescens, the latter being newly described here. A detailed description is provided for each species together with an identification key

Eumitrioid Usnea species are characterized by a tubular central axis throughout the entire thallus. Four species were identified in South America: Usnea baileyi is a (sub-) tropical species occurring both in continental South America and the Galapagos; U. perplectata has a scattered distribution worldwide and occurs in continental South America, mainly on the eastern range; U. flaveola and the newly described species U. subflaveola are both so far endemic to the Neotropical Andes. Distinct chemotypes, as well as anatomical characters, such as the thickness ratio of the medulla or the presence of medullar pigmentation, are diagnostic in delimiting these species. A detailed description of the species is provided together with an identification key

La paralysie de Todd est définie par une crise comitiale partielle suivie par un déficit neurologique temporaire. Ce déficit, partiel ou complet, est généralement unilatéral et dure entre 30 minutes et plusieurs jours avant résolution complète. Une paralysie de Todd peut aussi se présenter comme un trouble phasique ou un trouble visuel, avec le même caractère temporaire. Il est important de connaître l’existence de ce syndrome pour le distinguer d’un accident vasculaire cérébral accompagné de manifestations épileptiques, car l’approche thérapeutique est évidemment bien différente. Nous rapportons un cas didactique de paralysie de Todd, survenu chez une femme de 77 ans.

International audience; La paralysie de Todd est définie par une crise comitiale partielle suivie par un déficit neurologique temporaire. Ce déficit, partiel ou complet, est généralement unilatéral et dure entre 30 minutes et plusieurs jours avant résolution complète. Une paralysie de Todd peut aussi se présenter comme un trouble phasique ou un trouble visuel, avec le même caractère temporaire. Il est important de connaître l’existence de ce syndrome pour le distinguer d’un accident vasculaire cérébral accompagné de manifestations épileptiques, car l’approche thérapeutique est évidemment bien différente. Nous rapportons un cas didactique de paralysie de Todd, survenu chez une femme de 77 ans.