February 2016

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Types of sexuality in the European Ash, as a background to understanding types of sexuality in the Syrian Ash

Ophir Tal  ophirtal10@gmail.com
Avi Shmida, the Department of Evolution, Systematics and Behavior, and the Federmann Center for the Study of Rationality at the Hebrew University in Jerusalem, Givat Ram avi.shmida@gmail.com

Keywords: dioecious, insect pollination, wind  pollination, Oleaceae, gender, temperate forest, European trees, polygamous, reproduction in trees

Fraxinus is a genus of trees from the Oleaceae family, which includes species with various levels of gender separation, and flowering characteristics connected to a continuum between insect pollination and wind pollination.  The Syrian Ash (Fraxinus syriaca), which grows in Israel, is a hermaphrodite tree which bears on its inflorescence small androgynous  flowers that have neither a calyx nor a corolla, and are wind pollinated.  The European Ash (Fraxinus excelsior), on the other hand, presents a polygamous sexual model, with heterogeneity in the flowers and  individuals within the  population, with part that are only male or only female, and others that are at various, changing degrees of masculinity or femininity in different individuals. The sexuality of the European Ash was studied in detail By Ophir Tal in his doctoral thesis, and is summarized briefly in this article. The research results of the European Ash may shed light on the evolution of the development of sexuality in the various species of the genus, and on the allocation of male and feminine resources in the Syrian Ash that grows in Israel.

Full Hebrew version


Summary of the Kalanit study tour to the Arava and the Southern Negev 3-4, February, 2016

Avi Shmida, the Department of Evolution, Systematics and Behavior, and the Federmann Center for the Study of Rationality at the Hebrew University in Jerusalem, Givat Ram.  avi.shmida@gmail.com
Gadi Pollak, Kalanit editorial, gadpollak@gmail.com

Keywords: Eilat, Arava valley, adaptation to drought, Zygophyllaceae, annuals,  desert,  Brassicaceae, Negev, Sudanian, Chenopodiaceae, desert flowering, wadi  vegetation, thermophilic

The major flooding that occurred in the Negev and the Arava at the end of October 2015, and additional sporadic rain in November and December – resulted in widespread sprouting, probably in November. The heat that prevailed later on for four to seven weeks at the end of 2015, caused rapid growth and amazing flowering  of colorful patches of purple and yellow, especially on the road sides and the major Wadi channels.  The rain in the desert is extremely patchy, and accordingly stretches of green and small and fragmented carpets of flowering, separated by dry areas, appeared. The annual plants, which had germinated only two months previously, were dominant in the flowering. Among these the most prominent werespecies of the Brassicaceae family. The special weather conditions of this season also created an opportunity for the development of extreme desert plants, and many Sudanian plants, which do not appear every year.

Full Hebrew version


Summary of the Kalanit study tour to the Sharon and Emek Hefer, 17 February, 2016 

Gadi Pollak, Kalanit editorial, gadpollak@gmail.com
Avi Shmida, the Department of Evolution, Systematics and Behavior, and the Federmann Center for the Study of Rationality at the Hebrew University in Jerusalem, Givat Ram. avi.shmida@gmail.com

The study tour dealt with the study of the vegetation and flora of sand dunes, Kurkar (calcareous sandstone) and Hamra (red sandy loam) in Emek Hefer and the Sharon. Few and small patches of natural, or semi-natural vegetation still maintain a fair wealth of wild species, despite the dangers resulting from the limited area, the fragmentation and human activity in the built-up and agricultural areas around. Special emphasis was placed on species that are typical of sandy habitats in the Coastal Plain, and the relative wealth of endemic and endangered species. In addition, we paid attention to the similarity and difference  between the sand dune plants of the Mediterranean region Coastal Plain, and the desert sand dune plants.

Full Hebrew version

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