The Stigmas of Hibiscus have prominent hairs. The Stigmas of many plants secrete copious amounts to nutrient rich exudes which help to collect and stimulate the germination of compatible Pollen . This can include specific Recognition Factors which promote the germination of compatible pollen and inhibit the germination of alien pollen. It can be rich in Pectins which can be degraded by the Pollen Tube . This provides an easy route to the Ovary.
Some Styles are hollow .
The Pollen Tubes may grow along the secretary Epidermis or the space may be filled with a liquid which promotes the growth of the Pollen Tube. Lily Has a hollow style. The Pollen Tubes grow on the Epidermal surface which secretes water and nutrients which help the pollen tubes grow. The style of Tomato has densely stained Transmitting tissue. The Pollen Tube delivers the Sperm directly to the Archegonim or Egg.