Joan in Flowerland by Margaret Tarrant and Lewis Dutton.
Illustrated by Margaret Tarrant.
Undated, but I think it’s a reprint from 1950, as the 1935 first edition was published undated in blue cloth rather than the beige of my copy.
Hardback, no dustjacket.
Coloured frontispiece and 15 colour plates, plus many line drawings- all of children and various flower fairies.
Margaret Winifred Tarrant (1888 – 1959) was an English illustrator specialising in depictions of fairy-like children and religious subjects. She began her career at the age of 20, and painted and published into the early 1950s.
She was known for her children’s books, postcards, calendars, and print reproductions.
The book tells of Joan’s journey through Flowerland after falling asleep in the sun one day.
Bought in Fosters in Chiswick. Lovely shop.
Sometimes turns up on Amazon: Flowerland
Alice in the Internet 
Actually, I think your copy could be the 1st edition. The second (i.e. 1936 that I have) has blue covers and text + vignette in dark blue. The 1st edition was beige with red lettering and also green illustrations on the endpapers- It also had a white dust-jacket In my opinion, I think this book shows Margaret Tarrant at her best!
Ah, thanks! It’s so hard to tell sometimes…
Glad to be of some help….it seems that may editions of these early 20th century children’s books are undated, and by what I see on ebay, many people do not have a clue what dates apply to the books they have. By the way, I like your site and came across it during my searches with Alice related books and illustrators….very useful and informative.