Aug. 1, 1902.] 
THE TROPICAL AGRICULTURIST. 
79 
troduced this plant (and also theStachys), have failed 
to acclimatise it in France, owing to insufficient lieat, 
but M. Mjixime Cornu introduced it successfully into 
Madagascar, the Congo, Gaboon, the Soudan, and Indo- 
China, whence excellent repoits of it have been 
obtained, testifying to its value in countries where 
Potatos do not thrive. The tubers of Plectranthus 
even exceed in amount of starch and farinaceous pro- 
perties those usually cultivated in the colonies, and 
those of Stachys tuberifera (nffinis). There are several 
species of Plectranthus, and they are not easily identi- 
fied ; most of them are natives of tropical Africa. 
India, and Malaya. At Hanoi in 1898 four small 
tubers, the size of a nut, were planted in the botanic 
garden, and from these M. Lemarie raised gradually 
increasing crops of tubers, that in January, 1900, were 
Bs large each as as a hen's egg, and in their entire 
weight attained to 208 kilos., or about twice that 
number of English pounds. At the same time, very 
similar tubers were distributed which, when cultivated, 
showed such differences that they were determined 
to be distinct species. In the flowers the tint of blue 
and the position of the stamens with regard to the 
pistil varied. M. Gornu gave the first plant here men- 
tioned the name ot Plectranthus Coppini. Dr. fleckel 
prefers the name Coleus Coppini. MM. Pailleus and 
Bois received from Eeunion tubers of yet another 
species, known in the Transvaal ; these on trial proved 
to be those of P. tuberous (Coleus tuberosus). Is^'ow it 
is identified with P. ternatus. In 1887 the late M, 
Pierre, Director of the Libreville Botanical Garden, 
introduced the new vegetable into the Congo, where 
it was highly valued. The Potarjcr d'uu Curieux 
mentions yet a fourth species, Coleus tuberosus, cul- 
tivated in Ethiopia; this has since been identified with 
C. edulis. Various other species have also been reported 
from tropical districts, but some of these are doubtless 
identical with those already mentioned, and when the 
vegetable receives further attention, the list of distinct 
species will be diminished, The properties of the 
varieties are practically alike. In parts of Tonkin the 
Plectranthus tubers will fill an otherwise unfertile 
period between May and October, leaving the ground 
free for other crops the rest of the year. This remark 
applies to other countries also. M. Lemarie judi- 
ciously remarks that before drawing hasty conclu- 
sions or planting the new tubers on too large a scale, 
attention should be paid to developing those that 
»re largest of size, and in hastening on also the 
period of growth as much as possible. The species 
mentioned as producing edible tubers are Colens 
tuberosus (Malaya,) Coleus barbatns (East Tropical 
Africa, India), Plectranthus esctilentus (Natal), 
Plectranthus floribundus (tropical Africa), — Gardeners' 
Chronicle. 
OUR PRINCIPAL TIMBERS 
(By W. Maiden, New South Wales.) 
IRONBARK. 
We have four iroubarks : — 
1. The white or grey iron bark ; 
2. The narrow-leaved ironbark ; 
3. The broad-leaved ironbark; and 
4. The red ironbark, or mngga. 
(No.l) Eucalvjdas imniculata, Sm., is confined to the 
coast districts, and is paler than the others, although 
it varies in colour to a pinkish and even pale red 
colour, so that in the south it is sometimes known as 
" rod ironbai k" ; this is the hardest, toughest, and 
most esteemed of our ironbai ks. 
(No. 2) Eucahjptus creln, F. v. M., is very widely 
diffused. It is the principal ironbark in that enor- 
mous stretch of couuti'y bet^veen Dubbo and Pilliga, 
&c., and also forms a part of the ironbark conntr}' east 
ot Dubbj. Bnt in greater or less abundance is it 
found over the whole of the north-eastern fourth of 
the State. It is red in colour, is known in the tr.ido 
as red ironbark," and is a valuable timber. It is a 
narrow-leaved, drooping species, the most graceful of 
th° group. 
(No. 3) EucoJyptus SideypJdoia, Benth, — ThU is 
largely developed in the Clarence River Ironbark 
district, but it extends along the coast and for a con- 
siderable distance south of Port Jackson. Like the 
preceding one, it also is well developed in the interior, 
though not to so great an extent. It crosses the 
dividing range and is abundant north of Dubbo, and 
is more or less (diffused in the crcba country between 
the interior and the coast, but it is much lesa 
plentiful in most districts than creha. It is always 
known as red ironbark, and is a valuable timber though, 
occasionally it is too free to be classed as a best iron, 
bark. 
(No. 4) Eucalyptus sideroxylon A. Cunn. — This is par 
excellence the ironbark of the interior ; at the same 
time there are few districts of the State, even in the 
coastal belt, in which it is not found sparingly. It 
penetrates furthest into the interior of the ironbarks 
beitie found at least as far west as Nymagee and 
Mount Hope, is well diffused in the south-westeru 
portion of the State, where it is the only ironbark 
tree, and is the only ironbark that extends into 
Victoria. In the northern half of the State it is also 
found, but, as a rule, not forming dense forests. It 
is a less compact tree than the others, yields timber 
of a deep-red colour and, although the least valuable ot 
cur ironbarks, is a valuable timber, often the best in 
the districts in which it grows, 
RED HARDWOODS. 
Timbers of this colour are usually very durable, 
heoce people who have been victimised by receiving 
bad pale hardwoods frequently specify only red 
hardwoods. Bat even amongst red hardwoods we may 
have inferior timbers, some of the white gums, for 
example, having redwood. Our red hardwoods 
include — 
1. Red mahogany {E. resinifera, Sm.). 
2. Grey gum, which includes two species 
{E. Punctata, DC, and E- -propinqua, Deana .and 
(Maiden). 
3. Murray red gum (E. rostrata, Schlecht). 
4. Forest red gum (E. fereticornis, Sm.). 
5. Sydney blue gum {E, saligna, Sm). 
6. Woollybutt (.E. longifoUa, Link and Otto). 
The whole of these belong to the coastal belt, with 
the exception of the Murray red gum, whose principal 
habitat has already been indicated ; it also is found 
near wateoourses in the greater part of the western 
half of the State. 
Red mahogany is chiffly found in the north Coast 
districts, though it is sparingly found for many miles 
south of Sydney. It is of a rich-red colour, and is 
one of the most durable of our timbers. It has a 
fibrous bark, and is a handsome tree. 
Grey gums have bark of a dull grey colour, and 
somewhat blotched. The bark is a little roughish, in 
contradistinction to the smooth and even shiny ap- 
pearance of that of some of our gums. Grey gum is 
one of the most valuable timljers of New South 
AVales, and is one of the principal timbers to be relied 
upon as an ironbark substitute, and thus to arrest 
the depletion of our ironbark forests. The best des- 
cription of it as a timber lies in the fact that it 
is difficult to tell it from red ironbark on appearance 
only ; an expert usually discriminates between the two 
by noting the tensile strength of a fibre. It is re- 
markably durable timber, and the only cases in wh'"ch 
it should not be substitoted for ironbark are where 
the tensile strength of best ironbark is required. It is 
largely used and esteemed in New South Wales, and 
can be recommended with the utmost safety to the 
foreign buyer. 
Murray red gum is well and favourably known 
partly because it is the most gregarious of New 
South Wales trees. As with the Western Australian 
jarrah, so with Murray red gum, there is no 
difficulty in supplying a practically unlimited demand 
