Top 10 botany facts

4 meters (13 feet). The sequoias root system is wide spreading, but shallow. There is no taproot. A mature sequoia's roots can occupy over 1 acre of earth and contain over 90,000 cubic feet of soil.

The soil. The permafrost prevents trees from developing a deep root system. Climate variations or forest fires can thaw the upper extents of the permafrost, creating a ground slump called thermokarst.

Tobacco. Green Tobacco Sickness is a type of nicotine poisoning caused by the dermal absorption of nicotine from the surface of wet tobacco plants. The symptoms include vomiting, headache and fluctuations in blood pressure and heart rate. These may be so severe as to require emergency medical treatment.

It is poisonous to insects. Nicotine is a powerful neurotoxin to insects. Many plants other than tobacco contain it, however the concentration of nicotine in tobacco is exceptionally high. Even though some species have evolved the ability to feed on tobacco, it remains relatively easy to grow, being unpalatable to most species. In some places, tobacco became an invasive weed.

Two. Welwitschia is endemic to the Namib desert. The age of individual plants is difficult to assess, but many plants may be over 1000 (or even 2000) years old. Because Welwitschia only produces a single pair of foliage leaves, the plant was thought by some to be neotenic, consisting essentially of a "giant seedling." However, research showed that its anatomy is not consistent with the giant seedling idea. Instead, the plant is more accurately thought of as achieving its unusual morphology as a result of having "lost its head" (apical meristem) at an early stage.

Lignins are particularly important in the formation of cell walls, especially in wood and bark, because they lend rigidity and do not rot easily. Chemically, lignins are cross-linked phenolic polymers. Lignin constitutes 30% of non-fossil organic carbon and 20 to 35% of the dry mass of wood.

Violet. Since the ancient times, a black carrot has been grown in Asia (var. Atropururea), which was also brought to Europe during the Middle Ages. Through seventeen centuries, almost all of the carrots that were grown were violet. The modern carrot, a result of mutation, was first grown in the Netherlands. As it was sweeter and bigger, it quickly replaced the violet variety.

Traveller's tree. Ravenala, commonly known as traveller's tree is a palm resembling tree native to Madagascar. At the top of the tree are banana-like leaves, with pale midribs that give a fanlike appearance. It is named so because the water it accumulates in its leaf bases can be used in emergencies for drinking. However, the water inside the plant is murky, black and smelly and should not be consumed without purification.

Eucalypts. Eucalyptus regnans, the Australian mountain ash, is the tallest of all flowering plants. Today, the tallest measured specimen named Centurion is 99.6 m (327 ft) tall (taller than the highest giant sequoia). Six other eucalypt species exceed 80 metres in height.

Flower buds. The salted and pickled caper bud is often used in Mediterranean cuisine. Less often, the mature fruit of the caper shrub are also used, marketed as caper berries.