Spurge Olive

Dwarf olive tree ( Cneorum tricoccon )

The dwarf olive tree ( Cneorum tricoccon ), also called Dreibeeriger Zeiland, a plant belonging to the family Rutaceae is ( Rutaceae ). In older literature (eg Engler 1912), the genus Cneorum but is managed as a separate family dwarf Oleaceae ( Cneoraceae ).

Dissemination

Cneorum tricoccon is widespread in the western Mediterranean. In addition to the distribution on all Balearic Islands, the plant is also in the east and south of the Iberian Peninsula, in south-eastern France, Sardinia, Liguria and Tuscany before ( Straka et al 1976. Traveset 1995b ). As a typical location observes coastal maquis, in which the plant usually of 50-500 m above sea level, maximum up to 1000 m above sea level occurs ( Traveset 2002, Tébar & Llorens, 1997).

Designation

The species is mentioned for the first time in Tournefort (1700), which is the generic name Chamaelea ( Chamaelea tricoccos ) Tournefort coined, which later by Carl Linnaeus ( 1753) was changed to Cneorum L.. Urban ( 1918) describes a plant which he calls Cubincola trimera Urban and incorrectly classifies as Euphorbiaceae. This type, which was of Chodat ( 1921) renamed as Cneorum trimerum ( Urban) Chodat and assigned to the Cneoraceae growing endemic to the Sierra Maestra in the east of the island of Cuba ( Lobreau - Callen et al. 1978 Lobreau - Callen & Jérémie 1986). However, it seems in this case to act tricoccon an ecotype of C. ( Lobreau - Callen & Jérémie 1986), although according to Carlquist (1988 ) tricoccon significant differences in the wood structure of C. and C. trimenum there that he not only location adaptations returns. Should it be in C. trimenum not have to be a separate species, the distribution area of C. would tricoccon to the location of Cuba to expand. In any case, both species are closely related and their peculiar disjunction is surprising because C. tricoccon regarded as relict Mediterranean shrub that is supposed to have evolved under tropical conditions during the early Tertiary ( Traveset 1995a ), at a time in North America and Eurasia were already separated. Since the seeds of C. tricoccon not spread by birds, but of lizards ( Traveset 1995a, 1995b, Riera et al. 2002), a long-range transport of diaspores is hard to imagine. Lobreau - Callen & Jérémie (1986 ) describe the locations of Cneorum (C. tricoccon and C. trimerum ) in Cuba as undisturbed, difficult to reach and endemitenreich. Therefore, they go from an autochthonous species from and reject the alternative explanation that the plant was introduced with the introduction of sheep in the 18th century in Cuba, from. So, basically the explanation but only a creation of the kind before the separation of the continents.

Another species of the genus Cneorum, originally described under the name Cneorum pulverulentum Vent., Later in a separate genus Neochamaelea ( Engl ) Erdtman was treated as Neochamaelea pulverulenta ( Vent. ) Erdtman. It occurs only in the Canary Islands. It differs especially by pollen characteristics of the more common type Cneorum tricoccon from.

Description

Habit and leaf

Cneorum tricoccon is an almost hairless, evergreen shrub that rarely reaches heights of growth of more than 1 m, in exceptional cases, however, growth heights of 2 m reaches ( Riera et al. 2002). The change-constant leaves are sessile, entire, narrowly lanceolate. Stipules are not available ( Van Tieghem 1899, Straka et al. 1976). The leathery texture of the leaves and their somewhat curled leaf blades may be deemed xeromorphe adaptation.

Flowers and inflorescence

The small, yellow, andromonözisch distributed flowers are axillary, either individually, or in rare dreiblütigen, axillary Trugdöldchen ( Straka et al., 1976, Tébar & Llorens 1997, Caris et al., 2006 ). The flowers formula is C3 A3 K3 (G3). However, there are uncommon tetrameric flowers or those with only one or two carpels and leaves. Trimers flowers are in the Rutaceae an exception, and as the sister species forms Cneorum pulverulentum fourfold flowers that Trimerie is probably a reduction. However, there is no evidence of a fusion of leaf primordia during the Blütenontogenese ( Caris et al. 2006). Another derived character in the flower area also can be seen on a stamen circle the reduction. The sepals, the longer, lanceolate petals and episepalen, dithekalen and tetrasporangiaten stamens are free, the latter in three pits a powerful Diskusaufwölbung ( Androgynophor ) are inserted ( Daumann 1974 Caris et al. 2006). The Gynözeum consists of a post- genital syncarp, dreifächerigen and superior ovaries with a central angle constant placentation, which ends in a straight, long, ontogenetically late -developing pen with three flat oblong- egg-shaped scars ( Straka et al. 1976 Caris et al. 2006). The carpels are divided by a false, often incomplete septum into two compartments, in each of which a crassinucellate, anatrope and bitegmische ovule sitting ( Engler 1912, Straka et al. 1976 Boese angle 1984). In the course of seed maturation, the shape changes from anatrop after strong kampylotrop ( Boese angle 1984). Besides the aforementioned Diskusnektarium where the nectar is continuously stomata, which are distributed over the entire surface of Androgynophors, resigned, suspected Van Tieghem (1899 ) a Septalnektarium in the prime of Cneorum tricoccon. Within the ovary there are three septal gap spaces that flow into the pen base outwards. This gap spaces called Van Tieghem as Septalnektarien and he describes a nectar from the epidermal cells lining the clefts ( Van Tieghem 1899). Such secretion could not be confirmed by experiments Daumann (1974 ), which could only prove an intense nectar secretion of Diskusnektariums. Caris et al. (2006) suggest the gap spaces are a result of incomplete Synkarpie. Similar Septalspalten there are at Ruta chalepensis L. (as Ruta bracteosa DC Prodr, .. Schmid 1985) and Koelreuteria paniculata Laxm. from the closely related Sapindaceae ( Ronse de Craene et al. 2000 Caris et al. 2006). Furthermore, typical tricoccon for the flowering of C. are three lobed appendages, which are formed in the transition region between ovary and style and how the Androgynophor are equipped with stomata ( Caris et al. 2006).

Fruit

When the fruit ripens from December to July (flowering from November to June ) is a reddish-colored fleshy fruit that splits into three drupe fruits like part ( Straka et al. 1976 Traveset 1995b, Caris et al. 2006) developed. The decay of the fruit could loud Caris et al. (2006) the Septalspalten play a role.

Pollination

Pollination is by various Hymenoptera. Specifically Ceratina cucurbitina ROSSI. , Ceratina cyanea K., Halictus gemmens DOURS. , Halictus smeathmanellus Xylocopa violacea L. K. and be Daumann (1974 ) Apis mellifera L. (honey bee), known as pollinators in France. In Cabrera, where Apis mellifera not occur, Plagiolepis pygmaea occurs as an additional pollinators on ( Traveset 2002).

Pollen and chromosome number

The pollen is tricolporate and 35 x 29 microns in size ( Erdtman 1952) and the number of chromosomes is by Goldblatt (1976 ) 2n = 36

Seed dispersal

Cneorum is tricoccon saurochor and as containing the two lizards Podarcis lilfordi and P. pityusensis ( Lacertidae ) known. The fruits are eaten by the lizards. After passage through the intestine, the seeds germinate, so we must speak here of a endozoochory or Endosaurochorie ( Traveset 1995a, 1995b, Riera et al. 2002). Since about 250 AD, so after man weasels and snakes introduced in the Balearic Islands, the mentioned species of lizards on Mallorca and Menorca are considered extinct, so still must exist other distribution options. According Traveset ( 1995b ) later than weasels and snakes imported pine marten take (Martes martes ) and genet ( Genetta genetta ) dissemination. In contrast to the lizards, however, the dissemination by the carnivorous mammal does not seem to be very effective since the mammalian unlike the lizards do not remove all the fruit from the plant. So there is tricoccon in Menorca, only a small population of about 50 copies of C.. Fossil records indicate, however, indicate a larger spread in earlier times. As part of the conversion to other distributors also the locations of the plants seem to have shifted. In contrast to the fossil evidence ( lizard as containing ), suggesting a distribution of plants on the area between sea level to 500 m above sea level, the plants are to be found today up to 1000 m above sea level ( Riera et al. 2002). The reason for the martens and genets be mentioned in this context again, living mainly in higher elevations.