Catalogue Of New World Grasses Poaceae

Armen Takhtajan is among the greatest authorities in the world on the evolution of plants. This book culminates almost sixty years of the scientist's research of the origin and classification of the flowering plants. It presents a continuation of Dr. Takhtajan’s earlier publications including “Systema Magnoliophytorum” (1987), (in Russian), and “Diversity and Classification of Flowering Plants” (1997), (in English). In his latest book, the author presents a concise and significantly revised system of plant classification (‘Takhtajan system’) based on the most recent studies in plant morphology, embryology, phytochemistry, cytology, molecular biology and palynology. Flowering plants are divided into two classes: class Magnoliopsida (or Dicotyledons) includes 8 subclasses, 126 orders, c. 440 families, almost 10,500 genera, and no less than 195,000 species; and class Liliopsida (or Monocotyledons) includes 4 subclasses, 31 orders, 120 families, more than 3,000 genera, and about 65,000 species.This book contains a detailed description of plant orders, and descriptive keys to plant families providing characteristic features of the families and their differences.

Who knew there were so many bluegrasses in Mexico?ÿ This monographic study of the Mexican species of the large (500+ species), taxonomically complex, world-wide genus Poa, by Smithsonian researchers Robert J. Soreng and Paulÿ M. Peterson, revealed there were 23, including 2 new to science, and 2 previously unknown there.ÿ Two other narrow endemics were described only in the last 10 years. The Mexican species occur mainly in the mountains, and especially in the alpine.ÿ Most of the species occurrences in Mexico presumably reflect establishment during cooler climates of past glacial cycles. Today, several are living on the edge of extinction. Eleven natives are globally rare, or rare in Mexico. Breeding system diversity is high: asexual seed production is obligate in several and facultative in some others, one is dioecious, and some are gynomonoecious, several are perfect-flowered.ÿ At least 3 arrived by long-distance-dispersal from South America?s Andes; 2 aided by asexual reproduction, 1 by the capacity to self-fertilize.