chestnut burrs

"The Story of My Life" から引用します。
Sometimes I would go with Mildred and my little cousins to gather persimmons. I did not eat them; but I loved their fragrance and enjoyed hunting for them in the leaves and grass. We also went nutting, and I helped them open the chestnut burrs and break the shells of hickory-nuts and walnuts--the big, sweet walnuts!
"chestnut burrs" は栗のイガあるいはイガ栗を意味していると容易に推測できますが、 "burr" の意味にイガの説明を載せている辞書は余り見かけませんでしたが、下記の辞書には次ぎの説明が載っていました。
・Wiktionary: A bur; a seed pod with sharp features that stick in fur or clothing.
・Macmillan Dictionary: bur or burr the part of some plants that is covered all over with prickles (=small sharp parts) and contains the seed
・Merriam-Webster's Online Dictionary: (usually bur):
a) a rough or prickly envelope of a fruit
b) a plant that bears burs
"burr" よりも "bur" の方が使われるようで、 "bur" で引くとほとんどの辞書にイガの意味がありました。
・American Heritage Dictionary:
1) A rough prickly husk or covering surrounding the seeds or fruits of plants such as the chestnut or the burdock.
2) A plant producing such husks or coverings.
・Webster's New World College Dictionary:
1.the rough, prickly seedcase or fruit of certain plants, as the sticktight, cocklebur, etc.
2.a weed or other plant with burs
"burr/bur" には次ぎの興味深い意味もある事が分かりました。
・Cambridge Advanced Learner's English Dictionary: (also bur) a very small round seed container that sticks to clothes and to animals' fur because it is covered in little hooks.
この意味での"burr/bur" は "sticker" とも呼ばれるそうですが、この意味に対応する日本語が浮かびません。