الفهرس 
Introduction
Altitudinal variations in climatic factorsOnly 14 pages are availabe for public view
 |  | from | 266 |  |  |
| | | from | 266 | | |
Abstract
The current study was carried out at Saint Katherine Protectorate, South Sinai, Egypt, through 2016 and 2017. 94 stands were studied at 36 altitudes between 210 and 2129 m asl. Samples of soils at each altitude was taken for analysis. In addition, the plants were collected for identification and samples from the five studied medicinal plants (Cleome droserifolia, Origanum syriacum, Thymus decussatus, Achillea fragrantissima and Chiliadenus montanus) were collected for analyses. Seeds of three plants were collected.
The study divided into four main parts:-
A- Soil analysis: The results showed that most soil variables unchanged significantly along altitudinal gradient.
B- Phytosociology: In this study, 108 species were identified belong to 90 genera in 35 families. The data of species and soil variables were tabulated and analyzed by vegetation analysis programs. The results showed that:-
1) The plants clustered into four groups, where altitude was the more important factor affecting distribution of plants and determine the floristic composition.
2) DCA separated the species composition into 4 groups. group A was the most distinctive and separated one, group C was approximately close to group D, and group B was intermediate between groups A from one side and C and D from the other side.
3) Cleom droserifolia appeared in group “A” only which included the lowest altitudes (less than 700 m asl). Its associated species were Forsskaolea tenacissima, Acacia tortilis, Aerva javanica, Pulicaria incisa and Zygophyllum simplex.