Acanthaceae
Scientific classification
Kingdom: Plantae
Division: Magnoliophyta
Class: Magnoliopsida
Order: Scrophulariales
Family: Acanthaceae
Genera
  Acanthus L. -- bear's breech
  Andrographis Wallich ex Nees -- false waterwillow
  Anisacanthus Nees -- desert honeysuckle
  Aphelandra R. Br.
  Asystasia Blume
  Barleria L. -- Philippine violet
  Barleriola Oerst.
  Blechum P. Br.
  Carlowrightia Gray -- wrightwort
  Dicliptera Juss. -- foldwing
  Dyschoriste Nees -- snakeherb
  Elytraria Michx. -- scalystem
  Eranthemum L.
  Graptophyllum Nees
  Hemigraphis Nees
  Henrya Nees ex Benth.
  Holographis Nees
  Hygrophila R. Br. -- swampweed
  Hypoestes Soland. ex R. Br.
  Justicia L. -- justica, water-willow
  Nelsonia R. Br.
  Odontonema Nees -- toothedthread
  Oplonia Raf.
  Pachystachys Nees
  Pseuderanthemum Radlk.
  Ruellia L. -- wild petunia
  Sanchezia Ruiz & Pavón
  Siphonoglossa Oerst. -- tubetongue
  Stenandrium Nees -- shaggytuft
  Teliostachya Nees
  Tetramerium Nees
  Thunbergia Retz.
  Yeatesia Small -- bractspike
and about 200 more.
Ref: ITIS 34350 2002-09-07
For full list, see Kew

There are 234 genera and about 2500 species in the Acanthaceae.

A genus well-known to temperate gardeners is Acanthus, Bear's breeches, perennials with big (up to 1 m (3') tall) leaves and equally large flower spikes.

More tropical genera would be Thunbergia and Justicia.