Excerpt from Revision of North-American Species of Astragalus
In presenting this monograph of the most difficult genus of North American plants I have no excuse to offer, though many could be made. I know its shortcomings better than anyone else can know. There are Mexican species and a few others of which I would like to know more, but to wait ti’l we know all about all species would mean never publishing at all. I have tried to study every species in the field to get my knowledge first hand. I have used every means possible to get and keep fresh material for study. For the most part four per cent formaline has been the killer and preservative of section material as it causes the least shrinkage and distortion of tissue, but it is impossible to preserve any material in anything that will not cause some shrinkage. The celloidin method of infiltration and imbedding’ has proven the method of most service. Some tissues have been stained but for the most part sections have been left unstained and drawn from just as they are in order to get all detail’s. The method of drawing sections has been to mount sections and to project the images on the paper through a camera which magnifies them three times and to trace the image on the drawing paper with a pencil and when all details are complete to retrace them in ink. Most of the pods. Leaves and flowers were drawn by the use of proportional dividers, a. Few were drawn towards the last by the camera method.
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.
