Hibiscus (Hibiscus sp.), or rosemallow, flower and reproductive organs. The male reproductive structures include the anthers (yellow), which discharge pollen (male sex cells). Each anther is attached by filaments to a stamen tube (narrow, pink tube). At the top of the stamen tube are five stigmas (red, centre). These are part of the female reproductive system. The stigmas are attached to the style, which is a tube that runs down the inside of the stamen tube. The style links the pollen tubes, which grow from pollen stuck to the stigmas, to the ovules (female sex cells, not seen). Hibiscus are tropical flowers grown ornamentally for their colourful flowers.