OF PLANTS. 
405 
or four of these species as worthy of a particular notice, 
either by some singular mechanism, or by some peculiar 
provision, or by both. 
I. In Dr. Darwin’s Botanic Garden (1. 395, note,) is the 
following account of the vallisneria, as it has been observ¬ 
ed in the river Rhone.—[PI. XXXV. fig. 1, 2, 3.] “ Thev 
have roots at the bottom of the Rhone. The flowers of 
the female plant float on the surface of the water, and are 
furnished with an elastic, spiral stalk, which extends or 
contracts as the water rises or falls; this rise or fall, from 
the torrents which flow into the river, often amounting 
to many feet in a few hours. The flowers of the male plant 
are produced under water; and as soon as the fecundat¬ 
ing farina is mature, they separate themselves from the 
plant, rise to the surface, and are wafted by the air, or 
borne by the currents, to the female flowers.” Our atten¬ 
tion in this narrative will be directed to two particulars; 
first to the mechanism, the “elastic spiral stalk,” which 
lengthens or contracts itself according as the water rises or 
falls; secondly, to the provision which is made for bring¬ 
ing the male flower, which is produced under water, to the 
female flower which floats upon the surface. 
II. My second example I take from Withering. (Ar- 
rang. vol. ii. p. 209. ed. 3.) c< The cuscuta Europcea is a par¬ 
asitical plant. [Plate XXXVI.] The seed opens and puts 
forth a little spiral body, which does not seek the earth to 
take root, but climbs in a spiral direction, from right to left, 
up other plants, from which, by means of vessels, it draws 
its nourishment.” The “little spiral body” proceeding from 
the seed, is to be compared with the fibres which seeds 
send out in ordinary cases: and the comparison ought 
to regard both the form of the threads and the direction. 
They are straight; this is spiral. They shoot downwards; 
this points upwards. In the rule, and in the exception, we 
equally perceive design. 
III. A better known parasitical plant is the evergreen 
shrub, called the mistletoe. What we have to remark in it, 
is a singular instance of compensation. No art has yet 
made these plants take root in the earth. Here therefore 
might seem to be a mortal defect in their constitution. Let 
us examine how this defect is made up to them. The seeds 
are endued with an adhesive quality, so tenacious, that, if 
they be rubbed upon the smooth bark of almost any tree, 
they will stick to it. And then what follows? Roots spring¬ 
ing from these seeds, insinuate their fibers into the woody 
substance of the tree; and the event is, that a mistletoe 
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