Cnap. V. ROOT-CLIMBERS, 185 
Root-ciimbers—A good many plants come under this 
class, and are excellent climbers. One of the most 
remarkable is the Maregravia umbellata, the stem of 
which in the tropical forests of South America, as I 
hear from Mr. Spruce, grows in a curiously flattened 
manner against the trunks of trees; here and there 
it puts forth claspers (roots), which adhere to the 
trunk, and, if the latter be slender, completely embrace 
it. When this plant has climbed to the light, it pro- 
duces free branches with rounded stems, clad with sharp- 
pointed leaves, wonderfully different in appearance from 
those borne by the stem as long as it remains adherent. 
This surprising difference in the leaves, I have also 
observed in a plant of Maregravia dubia in my hothouse. 
Root-climbers, as far as I have seen, namely, the Ivy 
(Hedera helix), Ficus repens, and F. barbatus, have no 
power of movement, not even from the light to the dark. 
As previously stated, the Hoya carnosa (Asclepiadacee) 
is a spiral twiner, and likewise adheres by rootlets 
even to a flat wall. The tendril-bearing Bignonia 
Tweedyana emits roots, which curve half round and 
adhere to thin sticks. The Tecoma radicans (Big- 
noniacee), which is closely allied to many spontane- 
ously revolving species, climbs by rootlets; never- 
theless, its young shoots apparently move about more 
than can be accounted for by the varying action of 
the light. 
I have not closely observed many root-climbers, but 
can give one curious fact. Ficus repens climbs up 
a wall just like Ivy; and when the young rootlets 
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