Arundo donax
Arundo donax is a tall perennial cane. It is one of several so-called reed species. It has several common names including giant cane, elephant grass, carrizo, arundo, Spanish cane, Colorado river reed, wild cane, and giant reed. Arundo and donax are respectively the old Latin and Greek names for reed. Arundo donax grows in damp soils, either fresh or moderately saline, and is native to the Greater Middle East. It has been widely planted and naturalised in the mild temperate, subtropical and tropical regions of both hemispheres, especially in the Mediterranean, California, the western Pacific and the Caribbean and is considered invasive in North America and Oceania. It forms dense stands on disturbed sites, sand dunes, in wetlands and riparian habitats. Description Arundo donax generally grows to in height, or in ideal conditions can exceed . The hollow stems are in diameter. The grey-green swordlike leaves are alternate, long and wide with a tapered tip, and have a hairy tuft at the base. Overall, the plant resembles an outsize common reed (Phragmites australis) or a bamboo (subfamily Bambusoideae). A. donax flowers in late summer, bearing upright, feathery plumes long, that are usually seedless or with seeds that are rarely fertile. Instead, it mostly reproduces vegetatively by tough, fibrous underground rhizomes that form knotty, spreading mats which penetrate deep into the soil, up to deep. Stem and rhizome pieces less than long and containing a single node could sprout readily under a variety of conditions. This vegetative propagation appears well adapted to floods, which may break up individual A. donax clumps, spreading the pieces, which may sprout and colonise downstream. Biology Arundo donax is a tall, perennial grass in the subfamily Arundinoideae, characterised by C3 photosynthesis. The stems produced during the first growing season are unbranched and photosynthetic. In the Mediterranean, where a temperate climate is characterized by warm and dry summer and mild winter, new shoots of giant reed emerge around March, growing rapidly in June and July and producing stems and leaves. From late July the lower leaves start to dry, depending on seasonal temperature patterns. Drying accelerates during autumn when anthesis occurs from the beginning of October to the end of November. In this phenological stage moisture content falls significantly. In the low temperatures of winter giant reed stops its growth; regrowth occurs in springtime. Giant reed behaves as an annual in Central Europe where soil temperatures are low, due to poor freeze tolerance of the rhizomes. The base growth temperature reported for giant reed is 7 °C, with a maximum temperature of 30 °C. It has a high photosynthetic capacity, associated with absence of light saturation. Carbon dioxide exchange rates are high compared to other and species; maximum CO2 uptake ranged from 19.8 to 36.7 µmol m−2 s−1 under natural conditions, depending on irradiance and leaf age. Carbon dioxide exchange is regulated by leaf conductance. Studies have found this plant to be rich in active tryptamine compounds, but there are more indications of the plants in India