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Tubers and Root Vegetables...What is the difference? (RE: Sweetpotatoes) #216966
Asked October 14, 2014, 10:18 PM EDT
How are you? I am doing research on the different botanical Families in reference to sweetpotatoes for my own blog and I wish to learn as much as I can about Ipomoea Batatas. From my research there seems to be some vagueness in regards to what exactly is a sweetpotato. Some call it a root vegetable, others a tuberous root and others call it simply a tuber.
So I was curious ....what is the difference between root vegetables and tubers? Also, could a sweetpotato be described/called a "tuberous root"? In which case, is a sweetpotato considered a "tuber" or "root tuber" while a white potatoe is a "stem tuber" but also considered a tuber? In other words are they both considered to be tubers? Any thoughts, comments or suggestions you may have to get answers to these questions would be great appreciated!
Thanks so much,
Josh Kingdon
Worcester County Massachusetts
Expert Response
I recommend the book 'Producing Vegetable Crops' by Swiader & Ware for your research endeavors. In this book I found your answers.
Sweet potatoes, Ipomoea batats, is in the Sub-class Dicotyledoneae, and the Family of Convolvulaceae also known as the Morning-glory Family.
The part we eat is the root of this plant. The tissue swelling a tuberous root and is only root material. Your statement " Some call it a root vegetable, others a tuberous root and others call it simply a tuber", are all common names for the tuberous root. Sweet Potato tubers only contain root cells and grow on rhizomes. In order to grow a new sweet potato plant, part of the root cap must be present to have Sweet potatoes are not Yams but are commonly misnamed yams in the United States.
Potato, Solanum tuberosum, are in the Solanaceae or nightshade Family. It is not related to the sweet potato, but is related to the tomato, pepper and eggplant . Potato tubers consist of the enlarged or thickened portions of underground stems commonly called stolons. The tubers form at the distal end of the stolon and/or along the stolon itself. Tubers have all the characterists of normal stems, including nodes or eyes. A branch or stem can grow from the node to make a new plant.
To recap, sweet potato is a root tuber, potato is a stem tuber. Stem tubers have apical bud, nodes and internodes, scaly leaves and auxiliary buds, and the ability to develop chlorophyll when exposed to sunlight. Root tubers do not have these attributes. Both are considered vegetables.
Regards,
Carol Quish
Thanks so much for this informative response. I very much appreciate it.
However, I must admit I'm still a little bit puzzled...not by your well written summary but because on the same day I got a response from a university botany professor from a well known school who stated that the sweetpotato is not a tuber but is a root that has tuber like qualities. I'm just surprised that the botanical scientific community does not have a universally specific categorization of something as common as a sweetpotato. Thanks again...
The link below on basic botany will allow you to do your own research in the potato/sweet potato question. Look under the root section and also look under the stem section. Or check out other basic botany books for more information. . .
http://www2.ca.uky.edu/agc/pubs/ho/ho96/ho96.pdf
Regards,
Carol Quish
