Radiospongilla hemephydatia typically forms small, flat encrustations on aquatic plants, and its body surface is smooth and even. The oscula are not conspicuous, and the sponge’s skeleton is composed of irregular spicule fibers, held together by a small amount of spongin. The live sponge has a very soft and brittle consistency. The coloration of Radiospongilla hemephydatia ranges from dirty yellow to bright green, owing to the presence of unicellular algae, Chlorellae, living in their tissues. The megascleres are amphioxea, sharply pointed at both ends, slender, fusiform, and can be either entirely smooth or covered with a small number of indiscernible spines centrally. Their dimensions range from 290-330 µm in length and 9-12 µm in width. True microscleres are absent. Gemmoscleres in this species are amphistrongyla (blunt or rounded at both ends), more or less straight, club-shaped, and completely covered with minute, straight spines grouped terminally. The length and width of gemmoscleres range from 60-68 µm and 3-4 µm, respectively. Gemmules are rounded and numerous in mature sponges, loosely embedded in the skeletal network. The pneumatic coat is well-developed, thick, and consists of minute irregular air spaces, with gemmoscleres embedded rather radially in a single layer. The foramen tube is flask-shaped, slender, comparatively long, and porous. Gemmules have a diameter ranging from 310-370 µm.