TRUNK. 73 
a. Cum (culmus) is a term by which the peculiar stems of the grasses, and 
similar plants are usually designated in descriptive botany. It seems, however, 
an unnecessary distinction. 
187. Vine. This is a term denoting those stems which, being 
too weak to stand erect, creep along the ground, or any conven- 
ient support, and-do not throw out roots like the runner. The 
vine sometimes supports itself on other plants, or objects, by 
means of tendrils, as the gourd, and most of its tribe ( Cucurbita- 
cee); the grape-vine, &c. Such plants are called climbers. 
a. The tendril is a leafless, thread-like branch; or an appendage growing out of 
the petiole of the leaf; or it is the lengthened extremity of the midrib of the leaf. 
Its first growth is straight, and it remains so until it reaches some object, when it 
immediately winds and coils itself about it, and thus acquires a firm, though elastic 
hold. This beautiful appendage is finely exemplified in the Cucurbitacee and 
grape, above cited; also in many species of the pea tribe (Leguminosz), where it 
is appended to the leaves. 
188. The twining vine, or stem, having also a length greatly disproportionate 
to its diameter, supports itself on other plants or objects, by entwining itself 
around them, being destitute of tendrils. Thus the hop (Humulus) ascends into 
the air by foreign aid, and it is a curious fact that the direction of its windings is 
always the same, namely, with the sun, from right to left; nor can any artificial 
training cause it to reverse its course. This appears to be a general law among 
twining plants. Every individual plant of the same species revolves uniformly in 
one direction although opposite directions may characterize different species. 
Thus the Convolvulus revolves from left to right, against the sun. 
189. Trunx. This is the name given to the peculiar stems 
of trees. It is the central collum, or axis, which supports their 
branching tops, and withstands the assaults of the wind by 
means of the great firmness and strength of the woody or ligne- 
ous tissue in which it abounds. 
a, The trunk often attains to great dimensions. The white pine (Pinus 
strobus) of the American forest, with a diameter of 6 or 7 feet, sometimes attains 
the height of 180, or even 200 feet, with a trunk straight, erect, and without a 
branch for more than two thirds its length. * 
* At the first establishment of Dartmouth College, there was felled upon the college plain a 
tree of this species, measuring 210 feet in length. A Bombax of the South American forests, 
measured by Humboldt, was 120 feet in height, and 15in diameter. The Dagon tree on the 
island of Teneriffe, is said to be 16 feet in diameter. Trees of the genus Adansonia, in Sene- 
gal and the Cape Verd Islands, have been found of more than 34 feet in diameter. The 
famous Chestnut tree on Mt. Etna, often mentioned by travellers, is 64 feet in diameter, and 
consequently near 200 feet circumference. 
1* 
