330 Knox: STEM OF IBERVILLEA SONORAE 
be ‘“‘amber-colored”’ (21) and one and a quarter to one and a 
half inches long ; none has ripened in the greenhouse, as the flow- 
ers there are staminate only. The plant is able to persist in its 
arid habitat with remarkable vitality. In fact, so provident is it of 
water and nutritive substances that one in the museum case at the 
Garden which has been lying ona board since 1902 is in 1907 
still sending up yearly shoots bearing leaves and tendrils. Every 
fall the shoots die back and sprout again early the next spring. 
The Indians of the desert call the plant ‘“‘ Guarequi,” and a decoc- 
tion of its root is much used as a cathartic. 
The forms which show perennial growth among the Cucurbi- 
taceae are comparatively few in number, and many of them are 
tropical species or types seldom seen. Of those which have tuber- 
ous stems or roots the most familiar are Th/adiantha and Bryonia. 
The large slices of the Bryonia root are well known in pharmacy, 
and Weiss (10) refers to a root 20 cm. in diameter and 10 kg. in 
weight. More work has been done on Bryonia than on any other 
perennial form. It was pictured by Jacquin in 1774 as an example 
of perennial growth, and reference is made to it in most of the 
papers mentioned below. 
The history of /ervillea is given in full by Miss Emerson, so 
that only the most important citations are noted here. The first 
species of the genus was described by Gray (1) in 1850, from 
Texas and Mexico, as Sicydium Lindheimeri. In 1881 Cogniaux 
(11) separated from Sicydium the genus Maximowiczia Cogn., 
with three species. The first description of Maximowiczia Sonorae 
was published by Sereno Watson (21) in 1889. It was one of the 
numbers of the collection of Dr. E. Palmer found in 1887 about 
Guaymas, Mexico. Not only the range of MW. Sonorae but that 
of the entire genus is purely American. As the name Maximo- 
wicsta had been previously used for another genus, the name lber- 
villea was given to the present one by Greene (27) in 1895, and 
the species here discussed named by him as Jéervillea Sonorae. 
The only anatomical study of the genus has been made by Fischer 
(17), who included it in his thorough general survey of the family. 
It will be of advantage first to describe the normal structure of 
the Cucurbitaceous stem. The terminology used is that of Haber- 
landt (32), 
