Flowering plant magnoliid (2%) clades. The remaining 5 clades contain a little over 250 species in total; i.e. less than 0.1% of flowering plant diversity, divided among 9 families. The 43 most-diverse of 443 families of flowering plants by species, in their APG circumscriptions, are Of these, the Orchidaceae, Poaceae, Cyperaceae, Araceae, Bromeliaceae, Arecaceae, and Iridaceae are monocot families; Piperaceae, Lauraceae, and Annonaceae are magnoliid dicots; the rest of the families are eudicots. Double fertilization refers to a process in which two sperm cells fertilize cells in the ovule. This process begins when a pollen grain adheres to the stigma of the
Cattleya rex La Paz in Bolivia. It occurs in montane forests and low montane seasonally dry forests at 800–2500 m, growing on tree branches. In its native habitat, flowering occurs between December and March. "Cattleya rex" has been assigned an endangered conservation status in 1997 by the IUCN. Previously believed to be a Peruvian endemic, in 2013 a new locality was reported in Bolivia, thus increasing the area of extension for the species. "C. rex" requires a temperate climate (in winter, artificial heating set at 16 °C at night and 18 °C during the day is recommended) and good ventilation (a dark