Are Ornithogalum and Monstera both flowering plants?
no
Ornithogalum
Ornithogalum is a genus of perennial plants mostly native to southern Europe and southern Africa belonging to the family Asparagaceae.
 Some species are native to other areas such as the Caucasus.
 Growing from a bulb, species have linear basal leaves and a slender stalk, up to 30 cm tall, bearing clusters of typically white star-shaped flowers, often striped with green.
 The common name of the genus, Star-of-Bethlehem, is based on its star-shaped flowers, after the Star of Bethlehem that appeared in the biblical account of the birth of Jesus.
 The number of species has varied considerably, depending on authority, from 50 to 300.
Monstera
Monstera is a genus of about 50 species of flowering plants in the arum family, Araceae, native to tropical regions of the Americas.
 The genus is named from the Latin word for "monstrous" or "abnormal", and refers to the unusual leaves with natural holes that members of the genus have.
Monsteroideae
Monsteroideae is a subfamily of flowering plants in the Araceae family.
 It contains genera including: "Alloschemone", "Amydrium", "Anadendrum", "Epipremnum", "Heteropsis", "Holochlamys", "Monstera", "Rhaphidophora", "Rhodospatha", "Scindapsus", "Spathiphyllum", and "Stenospermation".
 The subfamily is notable for having many trichosclereids in the vegetative and floral parts of the plants, but rarely in the roots.