Study on the chorology of Hyssopus officinalis ssp. aristatus is carried out. Eight localities were mapped and resource characteristic of four of them was made. The anthropogenic impact on the distribution of the subspecies was estimated. A promising population is recommended for introduction.

The hyssop (Hyssopus officinalis L.) is a well-known and widely used medicinal and aromatic plant. In the Bulgarian flora naturally occurs only the subspecies aristatus while the subspecies officinalis, which is mainly applied in pharmacy and perfumery, is cultivated on small areas.

Bulgarian folk medicine applies the herb of wild-growing hyssop in cases of diseases of the respiratory and intestinal tract (6, 8). The essential oil content was found to be up to 1.4%. Its main components are 1,8-cineol (only traces in the hyssop oil from the typical subspecies) and isopinocamphon (9).

Hyssopus officinalis ssp. aristatus has limited distribution: on limestone as calcifil in Southwest Bulgaria (1, 3). The taxa is included in the list of plants with restricted regime of use (Order N 719/20.06.1989, Committee for Environmental Protection).

In recent years a team of Bulgarian scientists carried out comparative study on the essential oil content and composition and on the embryology of ssp. officinalis and ssp. aristatus (2, 4, 9). The phytocenotic role and ecological characteristics of ssp. aristatus were also clarified (7).

With the present study we aim to make resource characteristic of Hyssopus officinalis ssp. aristatus and elaborate recommendations for its sustainable use.

We focus our attention on mapping the hyssop populations in Southwest Bulgaria; determining the available reserves in some localities; determining the essential oil and flavonoid content in order to find population promising for introduction.

In the 1995-1996 period we studied 8 populations of Hyssopus officinalis ssp. aristatus. The investigation on the terrain we made applying the tracking method. The sites of localities were signed on maps with scale 1:1 500000 according to the UTM-Grid System. For more detailed determination of the sites we used geographic maps with different scales (1:50000-1:100000). Biological reserves of 4 localities were established on the basis of the herbage yield from 1000 m² according to the method with the concrete locality (5).

The essential oil and flavonoid content of samples from 6 and 4 populations respectively was determined according to pharmacopoeic methods (extraction by water distillation in Clevenger type microapparatus for the essential oil and extraction with acetone and hydrochloride for the flavonoids). Samples were gathered during the full blossoming and were air-dried.

Data obtained by mapping the populations are presented at Table 1.

The area of the localities was between 500 m² and 5000 m². All the populations inhabit places under anthropogenic pressure (along transmission lines, eroded terrenes after deforestation, etc.). Our observations coincide with the data published in the literature (7, 10) that Hyssopus officinalis ssp. aristatus spread on such places where conditions have become unfavorable for the primary species.

Reserve determination (Tab. 2) was made for the population with the best state (N 1), the biggest one (N 5) and two others (N 6 and N 8). The highest yield from 1000m² (air dried) was 51 kg (N 1) and the lowest was 9.8 kg (N 8). The biological reserves were the highest in locality N 1 (102 kg). Almost the same figure 95.2 kg for locality N 5 was due to its larger area. In the two other localities the reserves were quite lower, about 20 kg.

Phytochemical analysis (Tab. 3) demonstrated that one population (locality N 6) distinguished from the others with higher essential oil and flavonoid content: 1.41% (mean from two years) and 0.179%, respectively.

In conclusion we consider that the biological hyssop reserves on the territory of Bulgaria are limited despite the positive (to some extend) impact of the anthropogenic pressure on the distribution of the species in the investigated region. So that, gathering herbage from the nature is unadvisedly (economically as well as ecologically). In case of needs of crude drug of Hyssopus officinalis ssp. aristatus cultivation is necessary. For gathering material for introduction we recommend the promising population with higher essential oil and flavonoid content.

Heaving in mind the ability of Hyssopus officinalis ssp. aristatus to grow on places where the primary species are made away, we consider that the plant is appropriate for reinforcing eroded limestone terrenes, together with other species as Satureja montana ssp. kitaibelii, Artemisia alba, etc.

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2. Daskalova Ts. and Genova E. (1996): Histological structure of the Anthers and Microsporogenesis in Hyssopus officinalis L. ssp. aristatus (Godr.) Briq. Bot. Jahrbücher. Syst. 118 (3), 297-302.

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9. Tsankova E., Konaktchiev A. and Genova E. (1993): Chemical Composition of the Essential Oils of Two Hyssopus officinalis Taxa. J. Essent. Oil Res. 5, 609-611.

10. Velchev V. (1962): Trevnata pokrivka na varovitite tereni v rajona na Dragoman - Belidie han - Sofijsko, Sofia, 132.