44 
THE COTTAGE GARDENER AND COUNTRY GENTLEMAN, Afeil 20. 1858. 
MEMORANDA RESPECTING THE SAA-GAA-BAN, OR APIOS TUBEROSA, A SUPPOSED 
EQUIVALENT FOR THE POTATO. By tlie Vice-Secretary. 
Public attention having been drawn to this plant by 
persons who anticipate the possibility of its becoming a sub¬ 
stitute for the Potato, it is supposed that a few memoranda 
respecting its history and qualities may be found useful. 
This plant, called Glycine Apios, by Linnaeus; Apios 
tubcrosa, by modern botanists ; and Saa-yaa-ban, by some of 
the North American Indians, is a small trailing, tuberous 
perennial, with pinnated leaves, narrow lanceolate leaflets, and 
small brownish purple flowers, rather sweet-scented, and 
growing in axillary racemes, which are shorter than the leaves. 
It is described by North American botanists, as growing in 
damp, rich soils, along the margins of swamps in Carolina 
(Elliott, “ FI. Carol,” ii. 232), and in moist shady places from 
Canada to Florida, west to Missouri (Torrey and Gray, 
“Flora of North America,” i. 282) ; but Pursh asserts that it 
c \'strin^f !S!v tu t beros:1, A - An old tuber with * double string of voung ones b b 
°A ld ' f/ ’ * J he Up , per and wood ? P af t ofTe rin g 
section of the same 6 * ** A Cr0SS sectlon ol an old tuber, f. A longitudinal 
inhabits hedges and mountain meadows from Pennsylvania to 
Carolina (“ FI. Amer. Sept.” ii. 473). Its roots, that is to say, 
its tubers, are described by Elliot as small, and as having 
formed an article of food to the aborigines ; Nuttall calls them 
“ oblong cylindrical tubers, edible and farinaceous, much like 
those ot Lathyrus tuberosus , sold in some of the German 
markets, and rarely larger, though very numerous ” (“ Genera 
of North American Plants,” ii. 113) ; Pursh is the only author 
that I can find who speaks of them differently; he says, that 
the roots “ sometimes grow to an enormous size.” 
The plant itself is no stranger to our gardens. It is figured 
in the “ Botanical Magazine, t. 1198, and in other works. A 
rude woodcut, indeed, is to be found as early as 1640 in 
Parkinson’s “ Theatrum,” fol. 1062, at which time the plant 
w'as cultivated in England under the name of “ Terra glandes 
Americana sive Virginiance — Virginia 
Earthnuts.” The latter appellation seems 
to indicate in what estimation the plant 
was then held; it was regarded as a 
mere curiosity, with a “tuberous browne 
roote, which multiplies itself into sundry 
others.” 
As it is the tubers which some suppose 
likely to take the place of the Potato, the 
annexed cut has been prepared to show 
what they are, and how they are formed. A 
full-grown old tuber (a) is as large as a 
Golden V'tppen Apple, or a Nonpareil; it 
has a firm, rather hard, fleshy texture, is 
roundish in form, and bears irregularly a 
number of tubercles on its surface. These 
tubercles are eyes or buds ; some of them 
remain dormant; others, especially those 
near the upper end of the tuber, push into 
slender underground runners, which, after 
advancing a short distance, swell, then con¬ 
tract and lengthen again, then swell, and so 
proceed during the season of growth, until 
a string not very unlike a rude necklace is 
formed, as at b, b. Towards the end of the 
season these swellings diminish, or even dis¬ 
appear, and then a slender, cord-like, under¬ 
ground woody stem is all that is formed. 
The swellings, b, b, are young oval tubers, 
each furnished with an eye or two at the 
upper end. In a second season these strings 
of tubers enlarge considerably, form more 
eyes at their sides, become rounder, and 
assume such an appearance as is seen at c, 
d; the upper part, d, acquiring a more 
woody texture, and throwing up stems and 
leaves, or emitting other underground shoots. 
At what rate this swelling process advances, 
or how many years the largest tubers which 
have come under examination may have 
been in acquiring their size, I do not know ; 
certainly two years, at c, or more, and pro¬ 
bably several in such cases as a. 
When examined microscopically, the 
tubers are found to consist principally of a 
mass of large oval, very thick-sided cells, 
filled with starch, among which are scattered 
irregularly in the centre several woody 
bundles, composed of strangulated porous 
vessels of considerable size, very irregular 
and unequal laticiferous vessels, also much 
strangulated, and a few spiral vessels. Near 
the circumference, just within the bark, 
these bundles are arranged in distant nar- 
rovv plates, forming short rays, and offering 
indistinct traces of concentric zones (e). A 
considerable quantity of truncated prismati ■ 
cal raphides is found among the cellular 
tissue ; and around the central bundles of 
