Lathyrus cassius Boiss.

Lathyrus cassius Boiss. View in CoL

– Fig. 11A, B View Fig .

+ Bu: Bulgaria: Thracian lowland, Haskovo district, 1.5 km NE of Simeonovgrad town, 19 Jun 2021, Mátis & Miholcsa (obs.); ibid., 42.04326°N, 25.84557°E, 90 m, dry grasslands among sparse Paliurus spina-christi Mill. scrub, 15 Jun 2023, Stoyanov & Marinov (SOM 178626); ibid., 42.04386°N, 25.84665°E, 15 Jun 2023, Stoyanov & Marinov (SOM 178627, SOM 178628).

– This is the first record of Lathyrus cassius from Bulgaria. Up to now, Lathyrus L. was represented by 30 species in the Bulgarian flora ( Kožuharov 1976; Tosheva 2005). Lathyrus cassius , an E Mediterranean element, was known only from SW Asia ( Anatolia and the Levant) until a few years ago ( Davis 1970). It was recently reported for the first time for the European flora, from Edirne Province in European Turkey ( Güneş & Çırpıcı 2015). The Bulgarian locality of L. cassius is about 160 km N of the one from near Edirne and therefore now represents the northernmost outpost of the range of the species. Among the Bulgarian members of the genus, L. cassius is closely related to L. annuus L. The latter is a circum-mediterranean species, growing sympatrically with the former but in more humid, more or less scrubby habitats. Morphologically, the two species are well distinguished. Lathyrus cassius has pale pink flowers and its peduncles, calyx teeth and legumes are covered with more or less dense, sessile glands, whereas L. annuus shows yellow to orange-yellow flowers, without or with only a few, sparse glands ( Fig. 11C, D View Fig ). Furthermore, the legumes of L. cassius are 28–35 mm long, whereas those of L. annuus are 40–80 mm long ( Davis 1970). The two species also differ significantly in phenology: L. annuus blooms in the second half of May, whereas L. cassius a month later. The population of L. cassius occupies the S slope of a small hill NE of Simeonovgrad town and consists of about 100 individuals. The species grows in dry grasslands dominated by Aegilops speltoides Tausch and Hordeum bulbosum L., alongside other typical Mediterranean or submediterranean species such as Bituminaria bituminosa (L.) C. H. Stirt., Bupleurum odontites L., Convolvulus betonicifolius Mill. , Cota tinctoria (L.) J. Gay, Cruciata pedemontana (Bellardi) Ehrend. , Crupina vulgaris Cass. , Echinops microcephalus Sm. , Linum trigynum L., Pimpinella peregrina L., Polygala monspeliaca L., Rumex tuberosus L., Rapistrum rugosum (L.) All., Stachys obliqua Waldst. & Kit. , Teucrium capitatum L., Ziziphora capitata L. Due to extensive grazing, ruderal plants such as Bromus arvensis L., Cephalaria transsylvanica (L.) Roem. & Schult., Ononis spinosa L., Eryngium campestre L., Phleum paniculatum Huds. and Xeranthemum cylindraceum Sm. were also abundant in the grasslands.

A. Mátis, Z. Miholcsa, Y. Marinov & S. Stoyanov