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ABSTRACT

Commicarpus grandiflorus is recorded for the first time in Israel. The new record in the En Gedi area extends the known range of this species conspicuously northeast, with a gap of more than 300 km from the southern Sinai Peninsula to the Dead Sea. Morphology, habitat and plant community data are presented and discussed. A description of this newly recorded perennial herb is given and drawings of the plant were made from freshly collected specimens. A revised identification key for the genus Commicarpus in the Flora Palaestina area is provided. An estimation of C. grandiflorus population size in the En Gedi area is made. The plant is recommended for inclusion in the national Red List of Threatened Species.

In: Israel Journal of Plant Sciences

ABSTRACT

While plant mimicry by animals to make them cryptic from both prey and predators has received significant attention, the reverse situation, i.e. animal mimicry by plants as defense from herbivores, has been paid dramatically less. Here, in an essay intended to both stimulate and intrigue, I describe the various proposed types of defensive animal mimicry by plants, discuss the few published experimental tests of this hypothesis, and propose some future directions of research of defensive animal mimicry by plants. Animal mimicry by plants as defense from herbivores comprises two general types: direct animal mimicry, and mimicry of cues about animal action. The direct type includes bee, wasp, caterpillar, ant, aphid, beetle, butterfly, eye, and snake mimicry. The animal cue mimicry includes tunneling, chewing damage, spider web or arthropod silk, animal dung-shaped plants, and carrion and dung odors. These defenses include Batesian mimicry, masquerade, a mixture of Batesian mimicry and masquerade, and probably also perceptual exploitation. As an overlooked phenomenon, this area of evolutionary ecology has good potential for interesting finds.

In: Israel Journal of Plant Sciences

ABSTRACT

The ecological benefits of polyploidy are intensely debated. Some authors argue that plants with duplicated chromosome sets (polyploids) are more stress-resistant and superior colonizers and may thus outnumber their low ploidy conspecifics in more extreme habitats. Brachypodium distachyon (sensu lato), for example, a common annual grass in Israel and the entire Mediterranean basin, comprises three cytotypes of differing chromosome numbers that were recently proposed as distinct species. It was suggested that increased aridity increases the occurrence of its polyploid cytotype.

Here, we tested at two spatial scales whether polyploid plants of B. distachyon s.l. are more frequently found in drier habitats in Israel. We collected a total of 430 specimens (i) along a large-scale climatic gradient with 15 thoroughly selected sites (spanning 114–954 mm annual rainfall), and (ii) from corresponding Northern (more mesic) and Southern (more arid) hill slopes to assess the micro-climatic difference between contrasting exposures. Cytotypes were then determined via flow cytometry.

Polyploid plants comprised 90% of all specimens and their proportion ranged between 0% and 100% per site. However, this proportion was not correlated with aridity along the large-scale gradient, nor were polyploids more frequently found on Southern exposures.

Our results show for both spatial scales that increasing aridity is not the principal driver for the distribution of polyploids in B. distachyon s.l. in Israel. Notably, though, diploid plants were restricted essentially to four intermediate sites, while polyploids dominated the most arid and the most mesic sites. This, to some degree, clustered pattern suggests that the distribution of cytotypes is not entirely random and calls for future studies to assess further potential drivers.

In: Israel Journal of Plant Sciences

ABSTRACT

In 1836 Col. Francis Rawson Chesney, a British army officer, led an expedition to test the proposition that large iron vessels could successfully navigate the river Euphrates from southern Turkey to the Persian Gulf. The naturalist Dr Johann Wilhelm Helfer, his wife Pauline (later Countess Nostitz), and the surgeon-geologist William Francis Ainsworth made field observations and gathered natural history collections from along the banks of the Euphrates. Botanical specimens were processed by John Lindley and made available to Antonio Bertoloni of Bologna, who described a number of new species from the material. A partial catalog of this material has been compiled, noting the location of type specimens, and the collections have been localized as far as possible given the scanty evidence from the labels. A bibliography of references relevant to natural history from the extensive literature on the expedition is provided.

In: Israel Journal of Plant Sciences

ABSTRACT

Four Ambrosia species are currently identified in Israel: the invasive perennial species Ambrosia confertiflora DC., the naturalized perennial species Ambrosia tenuifolia Spreng. and Ambrosia psilostachya DC., and the casual annual species Ambrosia artemisiifolia L. In this study, we performed a comparative analysis of three species: A. confertiflora, A. tenuifolia, and A. artemisiifolia. We found differences in morphology, growth and flowering phenology and physiology that may explain, besides climatic constraints, the factors involved in the differing invasion status of these species in Israel. A. artemisiifolia and A. confertiflora use strategies typical of invasive species: rapid growth and regeneration, phenotypic plasticity and reproductive ability. These characteristics have enabled the spread of A. confertiflora in Israel. However, A. artemisiifolia has not become established in Israel due to the country's dry summers. The naturalized populations have survived in ecological niches in Israel for many years, but due to their slow growth and low numbers of viable achenes, they have not spread.

In: Israel Journal of Plant Sciences

ABSTRACT

Coastal sand dunes are susceptible to invasive plants that significantly alter these endangered ecosystems. Acacia saligna is a small Australian tree that has become a significant invasive plant in Israel and in many other Mediterranean countries. The aim of this research was to study the impact of A. saligna on the indigenous vegetation of three coastal habitats (sand dunes, inter-dune depressions, and aeolianite [sandstone] ridges) in the Nizzanim Long Term Ecosystem Research Nature Reserve, Israel. Plant observations were conducted in the spring, in the following site types: (1) sites planted with A. saligna and sites invaded by A. saligna; and (2) reference sites not invaded by A. saligna. A simple index, the aggregate ecological value, was developed in order to evaluate the impact and the ecological value of each habitat and site for conservation purposes. The results indicate that planting A. saligna and invasion by A. saligna changed plant community composition, reduced psammophyte species richness, caused the disappearance of most endemic, rare, and protected species, and overall reduced the ecological value of the Nizzanim Nature Reserve.

In: Israel Journal of Plant Sciences

ABSTRACT

The article provides an analysis of the current situation with lectotypification of the generic name Salsola L. (Chenopodiaceae/Amaranthaceae sensu APG) and recent nomenclatural “resurrection” of the generic name Kali Mill., following molecular phylogenetic findings. Here we present additional arguments in favor of our recent nomenclatural proposal on conservation of the generic name Salsola with S. kali L. as the conserved type. Another option is the typification of Salsola with S. soda L., in which case taxa of the S. kali clade are placed in the genus Kali Mill. (sensu Akhani & Roalson) in its new circumscription. Positive and negative taxonomic and nomenclatural outcomes of each solution are discussed. Our position regarding the typification of Salsola is reconfirmed. The final decision on the nomenclatural fate of Salsola will be adopted at the XIX International Botanical Congress in 2017, following decisions and recommendations of two committees of the IAPT, which will evaluate our Salsola conservation proposal and report if typifications done by Standley in the North American Flora are supersedable.

In: Israel Journal of Plant Sciences

ABSTRACT

The question of the spread of an aposematic or of an otherwise visually defended plant type within a non-aposematic or a visually non-defended population is a long-standing enigma that has received considerable theoretical attention. However, the spreading of aposematic or otherwise visually defended plant genotypes within a non-aposematic or a non-visually-defended population has never, as far as is known, been shown or studied in nature in wild plant populations. This study investigates the loss of the various simultaneous types of defensive coloration in the spiny thistle Silybum marianum by a mutation that occurred independently and found in 13 wild populations in Israel. Mutant plants have plain leaves rather than leaves of the zebra-like wild-type, which has a white network of stripes on the upper leaf surface. The mutants never spread beyond several dozen meters and usually only over several meters. The mutation has a simple developmental origin, since the white variegation is the result of small air spaces formed between the epidermis and the photosynthetic parenchyma (causing no loss of photosynthetic capacity in white areas), and the mutants have no such subepidermal air spaces. In order to examine the possibility of establishing a pure population lacking this type of defensive coloration, seeds of mutant plants were collected from two wild populations where they grew mixed with the wild-type and a pure mutant population was selected and maintained for 4 years. Thus, 13 cases of very restricted spread of the visually defenseless mutant demonstrate the probable contribution of the variegation to plant fitness, supporting the hypothesis that conspicuous leaf variegation functions as defensive coloration.

In: Israel Journal of Plant Sciences

ABSTRACT

A fully bibliographed thesaurus of the contributions by the late Avinoam Danin to the series “Med-Checklist Notulae”, “Euro+Med Notulae”, and “Euro+Med-Checklist Notulae” is presented. The contributions of Avinoam Danin to the Med-Checklist and the Euro+Med PlantBase projects over 35 years is evaluated with respect to taxonomic and floristic content, co-authors, and new area and status records. This part of Danin's work, only fragmentarily given in customary bibliographies, is documented in quotable detail. Cross-reference helps to commemorate the invaluable contributions by Avinoam to the inventorying of plant diversity in Europe and the Mediterranean.

In: Israel Journal of Plant Sciences

ABSTRACT

The phylogenetic structure of communities (PSC) reveals how evolutionary history affects community assembly processes. However, there are important knowledge gaps on PSC patterns for annual communities and there is a need for studies along environmental gradients in dry ecosystems where several processes shape PSC.

Here, we investigated the PSC of annual plants along an aridity gradient in Israel, including eight years, two spatial scales, the effects of shrubs on understory, and the phylogenetic signal of important traits. Increasing drought stress led to overdispersed PSC at the drier end of the gradient, indicating that species were less related than expected by chance. This was supported at a smaller spatial scale, where within the drier sites, communities in open – more arid – habitats were more overdispersed than those under nurse shrubs. Interestingly, some key traits related to drought resistance were not conserved in the phylogeny. Together, our findings suggested that while habitat filtering selected for drought resistance strategies, these strategies evolved independently along multiple contrasting evolutionary lineages. Our comprehensive PSC study provides strong evidence for the interacting effects of habitat filtering and plant–plant interactions, particularly highlighting that the conservative evolution of traits should not be assumed in future interpretations of PSC patterns.

In: Israel Journal of Plant Sciences