A class rating is an allowance to fly a certain group of aircraft that require training common to all aircraft within the group.
 A type rating is specified if a particular aircraft requires additional specialized training beyond the scope of initial license and aircraft class training.
 What aircraft require a type rating is decided by the local aviation authority.
 Almost all single engine piston (SEP) or multi engine piston (MEP) single pilot aircraft can be flown without a "type rating", but are covered by a "class rating" instead.
 An exception to this under European Aviation Safety Agency (EASA) regulations is the piston version of the Piper Malibu.
Piper novae-hollandiae known as the giant pepper vine is a common climber growing in rainforests of eastern Australia.
 It is related to the pepper plant.
 It grows north from Mount Dromedary in southern New South Wales to tropical Queensland.
Piper, the pepper plants or pepper vines (a term used for certain "Clematis" in older times), are an economically and ecologically important genus in the family Piperaceae.
Erigeron piperianus is a species of flowering plant in the daisy family known by the common name Piper’s fleabane.
 It has been found only in the state of Washington in the northwestern United States.
Peperomia pellucida (also known by common names pepper elder, shining bush plant, and man to man) is an annual, shallow-rooted herb, usually growing to a height of about 15 to 45 cm.
 it is characterized by succulent stems, shiny, heart-shaped, fleshy leaves and tiny, dot-like seeds attached to several fruiting spikes.
 It has a mustard-like odor when crushed.
 The family Piperaceae comprises about a dozen genera and around 3000 species.
 The genus "Peperomia" represents nearly half of the Piperaceae with the genus "Piper" making the rest.
Piperidine is an organic compound with the molecular formula (CH)NH.
 This heterocyclic amine consists of a six-membered ring containing five methylene bridges (–CH–) and one amine bridge (–NH–).
 It is a colorless liquid with an odor described as objectionable, and typical of amines. the name comes from the genus name "Piper", which is the Latin word for pepper.
 Although piperidine is a common organic compound, it is best known as a representative structure element within many pharmaceuticals and alkaloids.
Merriam Modell (19 May 1908 – 1 July 1994)) (born Miriam Levant in Manhattan, New York was an American author of short stories, suspense and pulp fiction, who wrote primarily under the pen name Evelyn Piper.
 Many had a common theme: the domestic conflicts faced by American families.
Nicandra is a monotypic genus of flowering plants in the nightshade family containing the single species Nicandra physalodes.
 It is known by the common names apple-of-Peru and shoo-fly plant.
 It is thought originally to have been native to Peru (known elsewhere as an introduced species and sometimes as a weed) and is found nowadays as a ruderal species in tropical, subtropical and, to a lesser extent, temperate areas all over the world.
 It has also long been cultivated as an ornamental plant for its attractive flowers and curious fruits (the latter sometimes dried for use in floral design) and has been adopted into the traditional medicine of countries far-removed from its original home.

Question: What do Piper and Nicandra have in common?
Answer: plants