Ogastemma pusillum

Ogastemma pusillum grows in the Elat
Mountains in Timna and Elat, and in the southern Arava near Samar, Elot and in the
vicinity of Wadi Gishron, a total of five verified sites. There are estimates
of a possible seven sites.

Sandy
wadis from eroded Nubian sandstone and weathered granite slopes in extreme
desert areas where the average annual precipitation is 30-40 mm.

The
genus Ogastemma is monotypic and O. pusillum is the only species in the genus. In
the past, O. pusillum was considered a
species in the genus Megastoma. However, it transpired that the species
description was not valid, as it lacked a detailed description. At the same time,
it turned out that the name Megastoma was also given to a section in the
genus Echiochilon and later to a new genus of algae. Therefore, the
genus and its single species have been re-described as Ogastemma
(Brummitt, 1982).

In
Israel Ogastemma
pusillum grows
together with two others small and similar (to the inexperienced eye) annuals
from the Boraginaceae family. Both have lilac-colored and larger flowers – Lappula
spinocarpos whose mericarps have protrusions and Gastrocotyle hispida
with drooping and round-reticulate mericarps.

·        
Ogastemma pusillum
is an annual that appears only in rainy years in the Elat area and in many dry
years does not appear at all. Due to its irregular appearance, it is difficult
to estimate the size of O. pusillum populations and the number of sites
where it occurs. In 2010, which was a particularly rainy year in the Elat
region, thousands of individuals were observed in the Samar area. This however,
is an unusual situation.

·        
Expansion of development in Elat
threatens the O. pusillum site near Kibbutz Elot.

·        
The species is
protected within the boundaries of the Timna Park in Israel.

·        
As far as is
known it does not appear in the red books of other countries and there is no
information regarding its threat level and conservation status in the countries
in its global range. 

Meticulous surveys should be conducted in the Elat
Mountains and the southern Arava in order to locate the plant at its documented
sites, to monitor it and try to find other sites.

Ogastemma
pusillum
is found throughout the Saharo-Arabian region from the Canary Islands and
Mauritania in the west to the Arabian Peninsula in the east.

Ogastemma
pusillum is a small annual desert plant growing in extremely few sites
in the Elat Mountains and Southern Arava. In dry years, it does not appear at
all in the field, but in rainy years, thousands of plants can develop. O. pusillum has a broad distribution in
the Saharo-Arabian region and is not globally endangered. The sites in its
range should be surveyed and their populations monitored.

Brummitt, R. K. 1982. Ogastemma, a new name for Megastoma (Boraginaceae). Kew Bull. 36: 679-680.