Per 《新华词典》: 兼有散文和诗的特点 — 'shares features of prose and poetry'. No line breaks, no rhyme, but written with poetic rhythm and density of image. The genre entered Chinese in the early 20th century via translations of Baudelaire and Turgenev; Lu Xun's 1927 collection 《野草》 (Wild Grass) is the canonical Chinese example.
mistakes
散 here is sǎn (third tone, 'loose / free'), not sàn (fourth tone, 'to scatter'). 散文 = 'loose-form writing' = prose. Don't read it as 'scatter-text-poetry'.
