Caracteres anatômicos de folha e caule de Calea uniflora Less., Asteraceae

Diversas especies de Calea sao utilizadas como medicinais e varios estudos quimicos tem sido conduzidos para identificar compostos relevantes no genero, no entanto, poucos enfocam aspectos morfoanatomicos. Este trabalho tem por objetivo caracterizar morfologicamente a folha e o caule de Calea uniflora Less., a fim de fornecer subsidios para a identificacao da especie. O material foi submetido as microtecnicas fotonica e eletronica de varredura usuais. A lâmina foliar possui epiderme uniestratificada revestida por cuticula delgada e estriada. Em ambas as faces, ocorrem estomatos anomociticos e anisociticos, alem de tricomas glandulares e tectores. Estes sao pluricelulares e unisseriados, com apice agudo. Os glandulares podem ser pluricelulares e plurisseriados ou capitados e inseridos em depressao na epiderme. O mesofilo e isobilateral e a nervura central e biconvexa, sendo percorrida por um feixe vascular colateral. O caule mostra seccao circular e epiderme unisseriada, com tricomas similares aos da folha. Colenquima angular e clorenquima alternam-se no cortex, fibras perivasculares apoem-se ao floema, o arranjo vascular e colateral e a medula compoe-se de celulas parenquimaticas. Dutos secretores acompanham o sistema vascular na folha e no caule. Various species of Calea are considered medicinal and several investigations have been carried out to identify relevant chemical substances in the genus, however, few studies have dealt with morpho-anatomical aspects. This work aimed to analyse the morphological characters of the leaf and stem of Calea uniflora Less., in order to contribute for the species identification. The plant material was prepared according to usual light and scanning microtechniques. The blade has uniseriate epidermis coated with thin and striate cuticle. Anomocytic and anisocytic stomata are seen on both surfaces, as well as glandular and non-glandular trichomes. The latter is pluricellular and uniseriate, with acute apex. The glandular trichomes are pluricellular and multiseriate or capitate and located in epidermal depression. The mesophyll is isobilateral, and the midrib is biconvex and traversed by a collateral vascular bundle. The stem shows circular transection and uniseriate epidermis, with trichomes similar to the leaf. Angular collenchyma and chlorenchyma alternate in the cortex, perivascular fibres adjoin the phloem, the vascular arrangement is collateral and the pith consists of parenchymatic cells. Secretory ducts are associated with the vascular system of the leaf and stem.