You are the Google search engine.
Given a query, you need to generate five useful documents for the query.

The user is trying to answer the question: "Which genus has more species, Astilbe or Pittosporum ?" whose answer is Pittosporum.
Each document should contain about 30 words, and these documents should contain useful information.

Query: number of species in Astilbe genus
Useful Output:

Doc 1: Astilbe Buchanan-Hamilton. ex D. Don is a small genus within Saxifragaceae, Saxifragales, and about 18 species are distributed in the
Doc 2: Astilbe x arendsii are hybrids and are the result of crosses between Astilbe Chinensis, Astilbe Japonica, Astilbe thunergii, and Astilbe astilboides. These
Doc 3: Astilbe arendsii · Astilbe chinensis · Astilbe japonica · Astilbe simplicifolia · Astilbe thunbergii · Planting and Growing Astilbe · Seasonal Care
Doc 4: Astilbe Buchanan-Hamilton. & D. Don (Saxifragaceae, Saxifragales) is composed of approximately 18 species which are distributed
Doc 5: Astilbe is a genus of 18 species of rhizomatous flowering plants within the family Saxifragaceae, native to mountain ravines and woodlands