. . . at P.S. 15, Manhattan, New York City, ca. 1921, by Paul & Co., via Library of Congress Prints and Photographs Division.
This hand-colored glass lantern slide was used by Frances Benjamin Johnston in her garden lecture series.
The original black and white photo may have been taken for the American Museum of Natural History in New York City. Its online photo collection has several 1921 pictures of P.S. 15 and P.S. 62 children working in their “nature rooms.”
enclos*ure 
Love this! Though I wonder if it would have appealed to me as a kid.
It was probably better than diagramming sentences, anyway.
I’m wondering if the flowers were brought in from the country or if the children grew them in the city.
It’s nice to think of urban public schools having nature rooms.
I actually liked diagramming sentences – for the most part.