POLLEN FLORA OF PAKISTAN – LXVIII
Pollen morphology 20 species of the family Alliaceae from Pakistan has been examined by light and scanning electron microscope. Pollen grains are usually bilateral, hetropolar mostly boat shaped, sexine thicker tor thinner than nexine. Tectal surface is mostly rugulate foveolate or subpsilate rarely reticulate. On the basis of apertural types 3 distinct pollen types are recognized, viz., Allium fedtschenkoanum –type, Allium grifthianum-type and Allium roylei-type.
A palynological study of the family Dipsacaceae in Egypt and its taxonomic significance.
Pollen morphology of nine species belonging to four genera: Cephalaria, Pterocephalus, Scabiosa, and Lomelosia of Dipsacaceae in Egypt has been investigated by light microscope (LM) and scanning electron microscopy (SEM). Pollen shape, size, exine ornamentation, number and characters of apertures present powerful characters for distinguishing between species. The pollen grains were tricolpate and triporate. Their shapes vary from spheroidal to oblate-spheroidal. Regarding the position of apertures, three types can be recognized viz., circumaperturate, angulaperturate, and planaperturate. Concerning sculpturing of the exine in proximal face, two different pollen types can be distinguished viz., spinulate and gemmate types. The exine ornamentation was found useful to distinguish between closely related genera such as Scabiosa and Lomelosia. A diagnostic key is given for all studied taxa based on palynomorphological characters (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Geographic And Environmental Influence On Maya Settlement Patterns Of The Northwest Yucatan: An Explanation For The Sparsely Settled Western Cenote Zone
Most settlement pattern research and GIS analysis of the ancient Maya of the Northern Yucatan have focused on water availability in a dry landscape where cenotes are often the only water source. While water is of paramount importance, permanent settlement secondarily requires farmable soil, a resource often as precious as water in many parts of the Yucatan. The dynamics between these resources reveal areas of ideal settlement and more challenging landscapes for which the Maya developed strategies to overcome environmental conditions. A region of the southwest "Cenote Zone", however, appears to have presented the ancient Maya with insurmountably poor environmental conditions despite abundant water resources. The lack of dense population and stone architecture in this area emphasizes the lack of a simple correlation between cenotes and settlement. This thesis uses GIS analysis to identify and explore such problematic settlement areas to better understand the factors and complexities involved in the more successful settlements of neighboring regions. iv This work is dedicated to my late father, who first introduced me to the Mundo Maya through a visit to the ruins of Tikal at the age of nine, and who instilled in me strength, curiosity, and a love for exploring the world. v ACKLOWLEDGEMENTS I'd like to acknowledge Dr. Arlen Chase and Dr. Diane Chase for providing such outstanding opportunities and instruction, and for leading by example both in the field and in the classroom. Dr. John Walker for his eye-opening perspectives, GIS instruction, inspiring hard-working attitude, and patience in the field. Dr. Clifford Brown and Dr. Walter Witschey for their invaluable correspondence and for their contributions to mapping and GIS data of Maya sites.