Passerina (plant) large enough to cover them. This gives the plants a characteristic plaited or corded appearance. The flowers of some species are borne in terminal spikes, whereas other species bear them in a four-flowered head. Bracts, usually broader than leaves and larger than the flowers, subtend each flower. This is one helpful distinction between specimens of "Passerina" and plants in the genus "Struthiola". The calyx has four sepals, forming a flask-shaped or subcylindrical tube. At the mouth the sepals spread into lobes that are shorter than the tube. There are no petals, but the lobes of the sepals are quite colourfully
Discodermia calyx species, among others with similar toxins, became increasingly studied and important in medicine, particularly relating to chemotherapy. In a later study, scientist concluded that the calyculin A, from "D. calyx," also blocks calcium influx by blocking non-selective ion channels in the cell. Later research looked into "D. calyx" as a species to look at the natural mechanisms that can be used to regulate the toxicity of calyculin A. Scientist found regulation through phosphorylation and dephosphorylation. These among other studies focus on regulation of the toxin as a characteristic of the sponge Discodermia Calyx because of its implications in the fight