Columbia Encyclopedia

Search results

500 results found

Harpestreng, Henrik

(Encyclopedia)Harpestreng, Henrik, or Henricus Dacus, d. 1244, Danish herbalist and medical writer. He probably studied at the medical school in Salerno, and was a canon at Roskilde Cathedral, then Denmark's eccles...

cryptogam

(Encyclopedia)cryptogam, in botany, term used to denote a plant that produces spores, as in algae, fungi, mosses, and ferns, but not seeds. The term cryptogam, from the Greek kryptos, meaning “hidden,” and gamo...

Douglas, David

(Encyclopedia)Douglas, David, 1798–1834, Scottish botanist. He made several journeys in North America between 1823 and 1834 to study American plants and sent to Scotland more than 200 plants and seeds then unknow...

transpiration

(Encyclopedia)transpiration, in botany, the loss of water by evaporation in terrestrial plants. Some evaporation occurs directly through the exposed walls of surface cells, but the greatest amount takes place throu...

blindness

(Encyclopedia)blindness, partial or complete loss of sight. Blindness may be caused by injury, by lesions of the brain or optic nerve, by disease of the cornea or retina, by pathological changes originating in syst...

endangered species

(Encyclopedia)endangered species, any plant or animal species whose ability to survive and reproduce has been jeopardized by human activities. In 1999 the U.S. government, in accordance with the U.S. Endangered Spe...

potato

(Encyclopedia)potato or white potato, common name for a perennial plant (Solanum tuberosum) of the family Solanaceae (nightshade family) and for its swollen underground stem, a tuber, which is one of the most widel...

fetal tissue implant

(Encyclopedia)fetal tissue implant or fetal cell therapy, implantation of tissue from a fetus into a patient. In experimental procedures, fetal brain tissue has been implanted in the brains of patients with Parkins...

transplanting

(Encyclopedia)transplanting, in horticulture, the process of removing a plant from the place where it has been growing and replanting it in another. The major requirement in transplanting (especially of larger plan...

streptococcus

(Encyclopedia)streptococcus strĕpˌtəkŏkˈəs [key], any of a group of gram-positive bacteria, genus Streptococcus, some of which cause disease. Streptococci are spherical and divide by fission, but they remain ...