The ‘fight’ between the plant and the snake was prompted

His eyes widened as they fell upon something strange. Something was moving slowly and cautiously along the gutter. The pale yellow and brown of the snake’s body glistened like a stream of flowing metal. By what mistake had the creature strayed into this unlikely place? Impossible to say. Yet there it was and its slow movements betrayed uneasiness and confusion.
As he watched it, his instinctive antipathy melted away. He could understand so well what the snake was feeling. He entered into the cold, narrow intelligence and shared its angry perplexity. Its movement were cramped, its advance difficulty and it was in constant danger of slipping over the edge. Now and then it lay still in dull reflection, nursing a cold anger that could find no vent.
Meanwhile the little plant bent downward by every puff of wind was beating its thin twings against the gutter like a birch. The snake seemed not to see the plant. It moved forward until a light touch from the twings fell upon its head. At this, it stopped and lifted its neck; the plant was now doing no more than lightly sway and dip. The snake, its head still reared, waited, flickering tongue. One could feel the angry heaving and straining in the sluggish brain-the dull red anger waiting to explode. Then came a strong gust sweeping along the wall and at once the twings thrashed down upon the furious head-thrashed down and beat it with a movement that seemed to osun both comic and dreadful. In a flash, the head reared itself higher, the neck drew back and there was a lunge at the twings and the empty air. O fatal act! To strike, the snake had been obliged to coil and its coiled body could not support itself upon the narrow ledge. No recovery was possible; it overbalanced and fell with a thud upon a small flat roof fifty feet below. There, osun saw the creature begin to writhe in agony. It could do no more than twist and turn upon the same spot
Osun was trembling but beneath his agitation there was a deep trouble wonder. Here was the little plants now waving with kind of jaunty cynicism and here was the snake writhing in agony. The world unquestionably was a place of mystery and horror. This was revealed in the writhing of the crippled snake in the jaunty waving of the innocent plant in the wind.