Desert plants tend to look very different from plants native to other regions. They are often swollen, spiny, and have tiny leaves that are rarely bright green. A desert always has a limitation of water but the temperature may be hot or cold, high altitude and cloudy like parts of Costa Rica or low altitude and windy like the Cape Preserve in South Africa. The strange appearance of these plants is a result of their remarkable adaptations to the challenges of the desert climate. Desert plants have developed three main adaptive strategies with diverse implementations often in different species with convergent evolution to the same form: succulence, drought tolerance and drought avoidance in annual plants. Each of these is a different but effective suite of adaptations for prospering under conditions that would kill plants from other regions. These differences often extend to the cellular level with the development of special structures to store water in leaves and stems, the periodic shedding of leaves, and special adaptations to even the basic photosynthesis process. Chlorophyll (the green pigment in plants) is the only known substance in the universe that can capture volatile light energy and convert it into a stable form usable for biological processes (chemical energy) through the Calvin Cycle and the enzyme RuBisCO. Green plants use blue and red light energy to combine low-energy molecules (carbon dioxide and water) into high-energy molecules (carbohydrates or starch), which they accumulate and store as energy reserves. There are at least three variations of photosynthesis, all of which use the same basic mechanism, C3 carbon fixation used by most plants, C4 carbon fixation used in about 3% of plants and the CAM (crassulacean acid metabolism) carbon fixation pathway that evolved in plants like cactus as an adaptation to arid conditions.
When I was in Arcata this spring to do some bird photography, I drove down to Humboldt Bay and stumbled upon the lovely Humboldt Botanical Garden. The Humboldt Botanical Gardens are at the southern edge of Eureka, California. The Gardens are near the South Bay portion of Humboldt Bay on the north side of College of the Redwoods. The Garden was organized by a small group of volunteers in 1991. The goal was to create an educational botanical garden in for the Northern California region. The garden opened in 2006, with more development completed by 2008. Its Lost Coast Brewery Native Plant Garden has an emphasis on the Humboldt region, but includes plants in the geographic area from the Rogue River to the north shore of San Francisco Bay, and inland to a north-south line running from Vacaville through Williams, Redding, Yreka, Medford, and along the Rogue River to its mouth. The Gardens are particularly interested in maintaining complete native conifer, Iris and Lilium occidentale (western lily) collections. They had a beautiful display of spring flowers which I thought I would share.