G6 MEMOIRS FROM THE DEPARTMENT OF BOTANY OF COLUMBIA COLLEGE, 
and Muhlenbeckia have their greatest development in the tropics. Besides these two 
characteristic distributions there are those genera like Polygonum and Rumex which 
flourish from the equator to the arctic zones, that is as far as flowering plants can exist. 
In the second place, in addition to this general distribution of generic areas, there 
are conspicuous cases of special limitations. For example, we find Hriogonum, one of 
the larger, and Nemacaulis and Centrostegia, among the smaller genera, confined for the 
most part to western North America, Oxytheca, Chorizanthe and Pterostegia to the western 
portions of North and South Ameria.  Polygonella and Thysanella are mainly in the 
southeastern United States, while Pterococeus and Calliphysa are confined to the plains 
and mountains of eastern Europe and western Asia. Notwithstanding this general and 
special variation in latitude and altitude and the broad and restricted geographical ranges, 
the genera all fall into a remarkably well defined family. 
The name Polygonum is a very ancient derivative, composed of the two Greek words 
moavg and yorv, meaning respectively many and knee or joint, alluding to the numerous 
nodes which are so conspicuous in the stems of many species. It appears to have been 
associated by the ancient writers with the group to which it was applied by Linnaeus and 
for which it has since been used. 
With Polygonum aviculare as a basis, Dr. Pickering’ gives the following history of 
the generic name: Heraclides Tarentina, a Greek physician, who lived in the third and 
second centuries B. C., is said to have prescribed this plant as a remedy against the flow- 
ing of blood from the ear. After him other Greek physicians, poets and botanists, such 
as Nicander, Magnus of Philadelphia and Charixenes seem to have alluded to the plant. 
The Greek botanist Dioscorides was the first to chiracterize a form as haying “numerous 
slender branches, creeping on the ground like grass, with fruit at each leaf.’ Various 
writers have given the credit of the name to different ancient botanists or pseudo-botan- 
ists. For example, Pfeiffer’ attributes it to Tournefort, Dietrich® and Greene* to Co- 
lumna, and Mueller’ to L’Obel. Linnaeus, who elevated botany into a pure science and 
whose time is the turning point from pseudo-botany to real scientific botany, took up the 
name Polygonum and associated it with the group of plants for which it now stands. At 
whatever time the historical botanist chooses to start and to whomever he sees fit to refer 
a genus, the scientific botanist for the sake of avoiding endless confusion and having a sure 
basis of departure, will not attempt in most instances to seek for names behind the Lin- 
naean period, certainly not beyond that of Tournefort. 
The first reference we have to Polygonwm deals with its real or supposed medicinal 
1Chron, Hist, Pl. 393. $Syn. Pl, 1319, 5Syst. Cen. Aust. Pl. 1: 31. 
2Nomencl. Bot. 2: 795. ‘Fl. Francis, 132, 
