Czechoslovakia Charity Issues Of 1919

Does anyone specializing in Czechoslovakia happen to know the back story for these? A block of each of the 6 values has been lightly attached to the printed sheets. The cancel is an Strawberry(?) shaped design in red and has the same date as appears on the sheets, October 28, 1919.
I would like to know why these were created and who might have produced them. As well, were they made at the time or at some point much later?

Something a stamp dealer ,stamp club,Philatelic exhibition or even the Czech Society of Chicago ,Detroit or Philly would create .

https://czechout.org/journal/10.pdf

Page 7

Thanks, NSK.

Interesting bit of Czech philatelic history.

I would disagree with the explanation in that *.pdf
(Limeleaf)
I suggest it is the shape of the Linden Leaf,
(The National Tree of the Czech Republic)

"In Berlin there is a street called Unter Den Linden - that means under the lime trees, girls" - The Prime of Miss Jean Brodie.

Interesting,
I Googled both leaves, and the Lime Leaf
Lime leaf was longer and boat shaped.

Linden leaves feature on may Czech stamps

Aha!
I stand corrected..........

Linden – Tilia spp.
More commonly referred to as Linden or Lime, this tree is not to be confused with Citrus medica, the tree that produces actual lime fruits. ... Both trees and the hybridised form have edible leaves, in addition to producing a flower that is much valued as a herbal tea.3

Excellent info, NFK. I shall add that to my album info for those souvenirs. Also I apologize for the description of the postmark as a strawberry. It was red. It was nearly lunchtime. And I was unduly influenced by the prospect of food. Definitely a leaf and if it was recognized at the time, I would most likely have called it lime.