As in other mammals, thermoregulation is an important aspect of human homeostasis. Most body heat is generated in the deep organs, especially the liver, brain, and heart, and in contraction of skeletal muscles. Humans have been able to adapt to a great diversity of climates, including hot humid and hot arid.
Japanese knotweed is a perennial weed, producing tall canes, up to 2.1m (7ft) in height during the summer. The canes have characteristic purple flecks, and produce branches from nodes along its length. These branches support shovel-shaped leaves.
Pennsylvania smartweed (Persicaria pensylvanica / Polygonum pensylvanicum), which is native to Alaska and grows in the Pacific Maritime ecogeographic region, can be distinguished from spotted ladysthumb and curlytop knotweed by a combination of characteristics listed in Table 1 below.Gray.eeds are lens-shaped to three-angled, black, smooth, and shiny (Welsh 1974). Persicaria maculosa Similar species: Spotted ladysthumb can be distinguished from curlytop knotweed by the presence of stiff hairs that are up to 3.5 mm long on the margins of the leaf sheathes and erect spikes with deep pink flowers.