Lavandula pubescens Decne., Ann. Sci. Nat., Bot., Sér.

Bordbar, Firouzeh & Upson, Tim M., 2021, TAXONOMIC REVIEW AND PHYLOGENETIC INVESTIGATIONS OF LAVANDULA FROM IRAN AND OMAN, Edinburgh Journal of Botany 78 (347), pp. 1-16 : 8-9

Lavandula pubescens Decne., Ann. Sci. Nat., Bot., Sér. 2, 2: 246 (1834). –

Type: Egypt, at the foot of Mt Sinai , vi 1832, N. Bové 55 (lectotype and isolectotype P [photos!]).

Figure 5 .

Description. See Upson & Andrews (2004).

Phenology. In Iran, flowers from February to October, curtailed by winter cold rather than drought stress. Inflorescences up to 10 cm long are common, bearing both flowers and fruit (see Figure 5D ).

Distribution. Southwest Asia ( Jordan and Palestine), Northeast Africa ( Egypt, Eritrea), the Arabian Peninsula ( Saudi Arabia and Republic of Yemen) and Iran (Bushehr Province).

Habitat and ecology. This species is found in the moist valleys on the northern slopes of Mount Khormoj and is known from two populations 5 km apart (see Figure 4 ). Here it is restricted to mesic environments in moist valleys on the northern slopes, which are recognised as part of the Saharo-Arabian floristic region ( Zohary, 1973).

One population grows on stony margins of date palm gardens and the other on rocky slopes and stony habitats accompanied by Mentha mozaffarianii Jamzad, a narrow endemic species previously recorded only from Hormozgan Province ( Jamzad, 1987; see Figure 5A ). It is clearly restricted to favourable microclimates away from the intense aridity typical of the area.

Conservation status. During field observations, about 30 individuals were counted in two populations with an AOO of about 12 km 2 and an EOO of 0.05 km 2. Lavandula pubescens is assessed as Critically Endangered (CR) in Iran [B1ac(ii+iii_iv)+B2ac(ii+iii+iv) + D] ( IUCN, 2012). Its occurrence with the other restricted species strongly suggests that these habitats need protection. Globally, it is of Least Concern (LC) ( Upson & Andrews, 2004).

Ethnobotany. This species’ essential oil is composed largely of carvacrol, caryophyllene oxide, β-bisabolene, p -cymen-8-ol, β-caryophyllene, carvacrol methyl ether and terpinolene, and has shown notable antibacterial and antifungal activity ( Chhetri et al., 2015; Ibrahim et al., 2017; Al-Badani et al., 2017). It has been the subject of many studies for its application in the production of palm oil ( Rashed et al., 2016) and honey ( Nuru et al., 2015). In Yemen it is used in folk medicine as a carminative, insect repellent and antiseptic ( Chhetri et al., 2015). No uses are recorded in Iran, and based on fieldwork it is little known to local people.

Specimens examined. IRAN. South, Bushehr Province: SE Ahram, Mokhdun village , 28°44′59.81′′N, 51°30′03.48′′E, 360 m, 3 x 2017, Bordbar 2902 ( MIR) ; SE Ahram, Ashi, 28°43′13.66′′N, 51°31′09.51′′E, 573 m, 3 x 2017, Bordbar 2903 ( MIR) ; ibid., 5 iv 2018, Bordbar 3121 ( MIR) .

Lavandula pubescens is a well-known species notable for its acrid and unpleasant smell; it has a diagnostic indumentum with short- and long-stalked glandular hairs and long simple hairs. The pinnatisect leaves, which are highly dissected two or three times, are characteristic (see Figure 5B ). It is a species of arid areas, as reflected in its woody rootstock and stem base from which annual stems are produced ( Collenette, 1985; Upson & Andrews, 2004).

Its previously known distribution followed the Syro-African Rift Valley, with the species occurring on mountains and hills along the Red Sea coast and reaching the Dead Sea depression in the north. Its occurrence in Iran is significant due to the large disjunction across the Arabian Peninsula.

Figures

Figure 4. Distribution of Lavandula in Iran: L. coronopifolia (circles), L. pubescens (diamond) and L. sublepidota (triangle).

Figure 5. Lavandula pubescens. A, Habit; B, leaves; C and D, close-up views of inflorescence. Photographs by F. Bordbar.