Abstract
Leaf architecture, ornamentation and estimation of lamina area have been described in a Mediterranean species, Myrtus communis grown under irrigation in Gulshan-e-Maymar, Karachi, Pakistan. Leaves opposite usually in 3’s but same twig may also show superposed opposite leaves in 2’s. Leaves simple, sub-sessile (petiole c 1mm) fleshy succulent, fine-textured, dark lustrous, green, stiff, and pinnately –veined and more shining dorsally. The main vein is paler in colour, impressed above and raised beneath (Ventral surface). Venation improminent except midrib. Dorsal surface is more shining than ventral surface. Lamina ovate-lanceolate. The apex angle (AA) averaged to 60.52 ± 1.17o and base angle (BA) averaged to 71.64 ± 0.77o i.e. BA was significantly larger than AA by a quantum of 11.12o (t = 10.22, p< 0.0001). AA and BA were mostly acute, only rarely obtuse in case of few deformed leaves. Leaves are aromatic when bruised. Smell is refreshing but taste is bitter. Aspect ratio of leaf (LB / LL) was found to be 0.4238 ± 0.0065 varying by a quantum of 15.42% i.e. the leaf shape was fairly consistent in M. communis. Young stem and leaf pubescent - hairs simple, unicellular, non-glandular, solitary, conical or slightly wavy. The scent glands were present both dorsally and ventrally. Scent glands density was quite higher (966.63 ± 15.212 per cm2 ) near dorsal epidermis than that near ventral epidermis (736.97 ± 16.563 per cm2 ). Scent glands averaged to 95.30 ± 1.52 µm (N= 150) in diameter varying from 62.50 to 150.0 µm. Leaf Hypostomatous. Stomata anomocytic but staurocytic on petals. The stomatal density on mature leaf averaged to 500.74 ± 8.1 per mm2 . Stomatal size averaged to 20.36 ± 0.34 µm in length and 17.29 ± 0.27 µm in breadth. With around 10.8% variation, the magnitude of multiplication factor k averaged to 0.6337 ± 0.0623 (0.4545-0.8485) – quite reliable for determination of lamina area using linear dimensions of lamina length and breadth.
