The California deserts remain one of the floristic frontiers in the United States with an estimated 6-10% of the plant species undescribed. Over the past 50 years, 25-30 new species have been discovered each decade, and 200 more species are expected to be added this century.
To this point, consider the following:
- The coastal redwoods in Del Norte, Colorado contain 90-125 plant species per 2 1/2 acres; an eastern Mojave Desert bajada has 85 – 120 plant species per 2 1/2 acres.
- The California deserts have 2,341 known native plant species – that’s 37% of the state’s entire native flora.
- About 350 species, or 15% are listed by the California Native Plant Society as threatened, endangered, or of special concern.
- Of the listed species, 140, or 43% of the plants flower in the fall, and are therefore unlikely to be found during the spring survey season.
- About 35% of desert plants are annuals which depend on seasonal rainfall (winter or summer) to germinate. Some may not be seen for years.
Jim Andre is the Director of the Sweeney Granite Mountains Desert Research Center & Sacramento Mountains Reserve and provided the information above during a presentation entitled, Recent Plant Discoveries in the California Desert. He spends the blooming seasons of the year surveying, discovering, mapping, and listing what he sees.
Desert plants have devised special adaptations for life in harsh climates. Some plants, like short-lived annuals, grow solely under favorable conditions, while perennial plants have underground roots for water and food storage which sustain new growth when conditions are right. Other desert plants survive all year with special adaptations such as long roots to get water deep in the soil, or branched roots to get water over a wide area. Waxy or hairy leaves allow for water retention and sun protection, while pin-like leaves reduce water loss.
Rainfall is the most critical influence on plant development, but other factors such as length of days, climate, temperature extremes, and light intensity also play a role in the life of plants. Still more factors influence plant size, time of bloom, leaf size, and other variables. For example, you might discover a 6 foot specimen of a plant that normally grows to a height of 3 feet.