Are Sanchezia and Pycnanthemum in the same family?
no
Pycnanthemum
Pycnanthemum is a genus of plants in the mint family (Lamiaceae).
 They are commonly known as mountain mints (or mountain-mints, mountainmints), though "the mountain mint" may also be any locally common species in particular.
 Some are known as koellias, after an obsolete genus name.
Sanchezia
Sanchezia is a genus of the plant family Acanthaceae.
 It is estimated to contain about 20 to 50 species.
 Members of this genus are shrubs, rarely small trees or herbs, occurring in the lowlands of tropical South and Central America.
 A close relative is "Suessenguthia", which looks quite similar.
Pycnanthemum virginianum
Pycnanthemum virginianum, the Virginia or common mountain-mint, is a plant in the mint family, Lamiaceae.
 It is a herbaceous plant with narrow, opposite, simple leaves, on wiry, green stems.
 The flowers are white with purplish spotting, borne in summer.
 Like most plants in the genus, the foliage has a strong mint fragrance when crushed or disturbed.
 It is native to the eastern United States and eastern Canada. Pycnanthemum incanum
Pycnanthemum incanum, with the common name hoary mountainmint, "mountain mint", wild basil or hoary basil, is a herbaceous perennial in the mint family. Sanchezia lampra
Sanchezia lampra is a species of plant in the Acanthaceae family.
 It is endemic to Ecuador.
 Its natural habitat is subtropical or tropical dry forests.
 It is threatened by habitat loss. Sanchezia sericea
Sanchezia sericea is a species of plant in the Acanthaceae family.
 It is endemic to Ecuador.
 Its natural habitats are subtropical or tropical moist lowland forests and subtropical or tropical moist montane forests.
 It is threatened by habitat loss. Pycnanthemum californicum
Pycnanthemum californicum is a species of flowering plant in the mint family known by the common name Sierra mint, mountain mint, and California mint. Pycnanthemum curvipes
Pycnanthemum curvipes is a species of flowering plant in the mint family known by the common name stone mountainmint.
 It is native to the Southeastern United States, where it is found in Alabama, Georgia, North Carolina, and Tennessee.
 Its preferred habitat is dry, rocky woodlands and outcrops. Pycnanthemum tenuifolium
Pycnanthemum tenuifolium, the narrowleaf mountainmint, slender mountainmint, common horsemint or Virginia thyme, is a plant in the mint family, Lamiaceae.
 It is native to eastern North America. Sanchezia parviflora
Sanchezia parviflora is a species of plant in the Acanthaceae family.
 It is endemic to Ecuador.
 Its natural habitats are subtropical or tropical moist lowland forests and subtropical or tropical moist montane forests.
 It is threatened by habitat loss.