Anatomia y usos de las hojas maduras de tres especies de Sahal (Arecaceae)de la Peninsula de Yucatan, Mexico

This paper describes the leaf anatomy of Sahat nmuritiiformis (Karst.)Oriseb. H. Wendl.. Sahat mexicana Mart, and Sabal yapa Wright ex Becc. three of ihe four most representative species of the Yucatan Penfnsula. in Mexico. These species are locally used: in the rtHjtlng of traditional homes, as food (fruits and apical huds), and in the production of hats, bnwms and handicrafts. Leaf samples were collected in secondary growth of lower montane rainforest in the state of Quintana Roc and in two home gardens in [he stale of Yucat ^ . Herbarium .samples were obtained, and samples of blade and petiole were fixed in fonnaline-acetic acid-alcohol. Cross incisions were made on the blade and petiole, and were dyed with safranin and toluldine blue O. The results show that 5. mauritiiformis and S. yapa are morphologically alike: both are tall, slim palm trees; the leaf in S. mauritiiformis is a shorter palm-like stniciure compared with the other two species. The shape of the main nerve, as seen in cross section, is rectangular in the three species. The hasluta in the three species is acuminate and adaxial. The foliar anatomic structure is similar in the three species, although there are some liitTerences. The adaxiai an abiwial epidermis ofthe blade consist of one layer and. superficially, ihe anticlinal walls are straight; the stomata are intercostal, of the tetracytic type, preseni on bolh surfaces in S. mexicana and S. yapa and only on ihe abaxial surface on S. mauritiiformis. The hypodermis is one layer thick in S. yapa and in S. mexicana and [wo layers thick in S. mauritiiformis. In the three species the palisade parenchyma consists of several undefined strata as the cells are similar -in shape and size- to the ceils in the spongy parenchyma, so there is no marked difference between these strata and the spongy parenchyma seems almost continuous. Both fibrous and vascular bundles are disiribuied between the hypodermis and the palisade parenchyma; the fiber bundles can be found towards the abaxial surface wbile the va.scular and fiber bundles are located towards the adaxial surface. The fibers, in the three species, are elongated, with [he pointed tips, undivided and unseptaied. One to three wide vessels of meiaxilem can be .seen in the vascular bundles, those in S. yapa being [he widest in diameter. The vascular bundles are surrounded by [hick fiber shea[bs which come in pairs. The anatomic structure of e petiole is similar to thai of the blade, and is characterized by the many vascular and liber bundles dispersed in the parenchyma[ous tissue, and which arc very resistant. The histological structure of the hiade and petiole reflects strength and flexibility, qualities which make these plants adequate in the construction of roofs for rural housing and other buildings.