Plant root information resources

Heya,
I was wondering if anyone can pass along recommendations on resources to help understand the various root systems of different plants, including annual and perennial vegetables and fruit shrubs and trees?

Thanks so much!

Here are 2 books, published in 1926 & 1927.
They (and many more), are free downloads from the Soil and Health Library in Australia.

Root Development of Vegetable Crops
Root Development of Field Crops

WOW, I love those old books! Thanks John !

John Polk wrote:Here are 2 books, published in 1926 & 1927.
They (and many more), are free downloads from the Soil and Health Library in Australia.

Root Development of Vegetable Crops
Root Development of Field Crops

John Polk,
Thank you so very much for sharing these resources. The illustrations are wonderful. Much obliged.

Best,
JP

That Soil and Health Library is a tremendous source of old books.
Their home page links to their 4 sections, but they have another section (homesteading) that is not listed there - perhaps they haven't updated the site recently. http://www.soilandhealth.org/03sov/0302hsted/0302homested.html

Australian copyright laws are different than ours. Once a book goes out of print, it becomes 'fair game' for libraries to lend:

Australian libraries are allowed to provide clients with electronic copies of copyrighted materials for purposes of study only when it has been first determined that these materials are out of print and cannot be obtained through the usual channels of retail trade.

Sounds reasonable to me !