Walter Housley Wellhouse
Published: 2016-08-25
Total Pages: 104
Get eBook
Excerpt from The Insect Fauna of the Genus Crataegus: A Thesis, Presented to the Faculty of the Graduate School of Cornell University for the Degree of Doctor of Philosophy The genus is placed by many botanists in the family Rosaceae. Other botanists have divided the Rosaceae group and formed an apple family, Malaceae, in which Crataegus is included along with Malus, Pyrus, Cydonia, Mespilus, Sorbus, Amelanchier, Aronia, and Eriobotrya. The determination of species of Crataegus is as great a taxonomic problem to botanists as the determination of the parasitic Hymenoptera is to entomologists. During the first ten years of this century about one thousand species of Crataegus were described in North America. Many of them are now regarded as hybrids and varieties, and a still further reduction of species is in progress. This taxonomic uncertainty makes it impossible in many cases to recognize specific hosts for the insects that feed on the hawthorns. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.