Southwest Desert Flora

The Solanaceae, Nightshade or Potato Family is a large and important family of flowering plants. Members have a broad range of geographic distribution, world-wide with most in tropical areas especially in North and South America, others in sub-tropical and temperate regions of North America. Australia also has significant populations. Species are found in a wide range of habitats, morphology and ecology. The family includes a broad range of general forms including annuals, biennials, perennials, shrubs, small trees, vines and lianas.

The Plant List includes more than 110 genera and over 2,600 accepted species names. In North America, the US Department of Agriculture reports over 40 genera with more than 300 accepted taxa overall.

The largest genera is Solanum with nearly ½ of all Solanaceae species. Solanaceae contains plants of significant economic important including agricultural crops, medicinal, spices, weeds and ornamental species. Plants of great economic importance would include the potato (Solanum tuberosum), tomato (Solanum lycopersicum), peppers (Capsicum spp.) and tobacco (Nicotiana spp.). Poisonous plants include the Jimsonweeds, various Nightshades (Solanum spp.). One species Belladonna or Deadly Nightshade (Atropa belladonna) has both poisonous and medicinal properties.

General plant characteristics: Growth: annual or perennial, some plants have poisonous alkaloids, others important foods; Stems: stellate or branched pubescence; many with prickles; Leaves: simple or compound, alternate, exstipulate; Inflorescence: cymose; Flowers: bisexual and actinomorphic; solitary or clustered, corolla is sympetalous, sepals and petals usually 5 and 5, flowers often conspicuous and showy, insect pollination; Fruit: often a berry or capsule.

In the southwestern United States there are approximately 26 genera in Solanaceae. The largest genera in the southwest include Solanum, Physalis and Lycium. Arizona has approximately 13 genera with 55 species.