Possible Clues:

• That little flower - Sh! That makes it sharp
• Tiny crustaceans, a thousand lost in stream
• Flowing water comes from river, not well
• A very small brook
• If it's under five hundred, such a stream could be a bore
• Burn badly on back of boiler
• Sick at last of this sort of little flower
• Are, in short, sick of being like 26 across
• Brook this - well, not at last
• Tiny brook