Two new chasmophytic species of Silene (Caryophyllaceae, sect. Siphonomorpha) from Iran Author Jafari, Farzaneh Department of Plant Sciences, Faculty of Biological Sciences, Alzahra University, Vanak, 1993893973 Tehran, Iran. f.jafari@alzahra.ac.ir Author Keshavarzi, Maryam Department of Plant Sciences, Faculty of Biological Sciences, Alzahra University, Vanak, 1993893973 Tehran, Iran. m.keshavarzi@alzahra.ac.ir Author Doostmohammadi, Moslem Department of Biology, Faculty of Science, Shahid Bahonar University of Kerman, P. O. Box 76169 - 133, Kerman, Iran. doost@sci.uk.ac.ir Author Mirtadzadini, Mansour Department of Biology, Faculty of Science, Shahid Bahonar University of Kerman, P. O. Box 76169 - 133, Kerman, Iran. mirtadz@uk.ac.ir text European Journal of Taxonomy 2023 2023-02-20 860 42 61 http://dx.doi.org/10.5852/ejt.2023.860.2049 journal article 54447 10.5852/ejt.2023.860.2049 f3024132-3d29-4ccd-a73d-4378b96c9147 2118-9773 7674396 Key to S. penduliflora F.Jafari, Keshavarzi & Doostm. sp. nov., S. thyrsiantha F.Jafari, Mirtadz. & Keshavarzi sp. nov. and close relatives 1. Stems non-viscid; synflorescences densely thyrsoid, pedicel < 4 mm ; calyx < 8 mm ........................ ....................................................................................................... S . parrowiana Boiss. & Hausskn. – Stems viscid; synflorescences laxly thyrsoid, pedicel> 4 mm ; calyx usually> 8 mm ...................... 2 2. Calyx 7‒11 mm ; pedicel 5‒9 mm ; capsule 6.5‒9× 2.5‒5.5 mm ....................................................... 3 – Calyx 8‒10 mm ; pedicel (4.5‒) 5‒16 mm ; capsule 4‒6 × 3‒4 mm .................................................... 4 3. Basal leaves 5‒32 × 2‒4.5 mm ; calyx 7‒9 mm ; petal limb 2‒3 mm ; capsule 6.5‒7 × 2.5‒3 mm ........ ............................................................................................ S . ghahremaninejadii Hoseini & Assadi – Basal leaves 11‒60× 2.5‒4 mm ; calyx 9‒11 mm ; petal limb 5‒6 mm ; capsule 7.5‒9× 4‒5.5 mm .... .................................................................... S . penduliflora F.Jafari, Keshavarzi & Doostm. sp. nov. 4. Stem non-thick; pedicel (4.5‒) 5‒16 mm ; petal limb ca 5 mm ; claw glabrous; seeds 0.8 × 0.6–0.7 mm ; seed testa cell margins V-shaped; distribution: Isfahan Province ........................................................ ..................................................................... S. thyrsiantha F.Jafari, Mirtadz. & Keshavarzi sp. nov. – Stem thick; pedicel 6‒12 mm ; petal limb 5‒5.5 mm ; claw ciliate; seeds 1.1 × 0.8 mm ; seed testa cell margins U-shaped; distribution: Semnan Province ....................................... S . shahrudensis Rech.f.