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AOTUS DRUMMON DII.—ON THE RESPIRATION OF PLANTS. 
AOTUS DRUMMONDII* 
'J7 
IffilHIS yery fine Swan River shrub has been raised by Messrs. A. Henderson & Co., of the Pine Apple 
A Nursery, from Mr. Drummond’s seeds, and promises to be one of the most desirable of greenhouse 
shrubs for exhibition or decorative purposes. Our figure was prepared from Mr. Henderson’s plants 
in April last; since which time we have received from Messrs. Knight & Perry, of the Exotic Nursery, 
Chelsea, another form of it, differing only in being somewhat larger in all its parts. This was also 
raised from Drummond’s seeds, and is, we presume, one of those natural variations which are so 
frequently met with among seedling plants. 
The habit of this Aotus Drummondii is remarkably good, being stiff-branched and spreading. The 
branches are pilose, with short spreading hairs, and clothed with scattered sub-opposite or sub-whorled 
leaves, which are linear-acute at both ends, and are stalked, the petioles being also pilose. The upper 
surface of the leaves is plane, smooth, excepting a few scabrous elevations near the revolute margin; 
the lower surface is smooth, with a prominent midrib, on which occurs a few short scattered hairs. 
They are half an inch or more in length (in Messrs. Knight & Perry’s plant fully an inch), the larger 
about one-eighth wide. From the axils of the leaves spring the flowers, either solitary, or more 
frequently two or three together, borne on hairy pedicels scarcely so long as the calyx. The calyx is 
bell-sliaped, two-lipped, with nearly equal teeth, those of the upper lip being erect and largest, those 
of the lower lip reflexed, all pilose externally and smooth'within. The flowers are clear bright yellow, 
the roundish standard only being marked at its base by a small rayed zone of bright red ; the wings are 
oblong, slightly exceeding the paler yellow keel. The stamens are slightly longer than the slender 
tapering style, but inclosed by the keel. The ovary is villose, and bears one ovule.—M. 
OK THE RESPIRATION OE PLANTS. 
EHIHE idea generally entertained of the respiration of plants is, that it is a process by which carbonic 
A acid is decomposed, and oxygen evolved in a free condition, as a gas, into the atmosphere, this 
operation going on most actively under the direct influence of the sun’s rays. But it has long been 
known that there exists also in vegetable life a process by which carbonic acid is set free, as it is in the 
respiration of animals, and this process, observed most distinctly in plants removed from the sun’s light, 
is one respecting which much obscurity still prevails. In drawing especial attention to this process as 
occurring so generally in plants or parts of plants devoid of chlorophyll, I remarked,! some years ago, 
that from its evidently general occurrence it must be a true vital process, and not merely a result of a 
destructive or decomposing action of oxygen upon the vegetable tissues and their contents. 
Some very interesting experiments have been recently published by M. Garreau, of Lille, which 
throw much light upon the conditions of this exhalation of carbonic acid from living plants. He 
finds that it takes place not only in the absence of the sun’s light but in the full sunlight, and simul¬ 
taneously with the evolution of oxygen, the much greater quantity of the latter, together with the 
process of reabsorption of the evolved carbonic acid under such circumstances having disguised this 
fact in the experiments of most previous observers. 
M. Garreau placed branches, and other portions of living vegetable structures, under conditions in 
which he could fix any carbonic acid set free (by means of solution of caustic baryta), and thus 
remove it completely from the liability to be re-absorbed by the green parts of the plants under the 
influence of sun-light, and the result of numerous trials, was to show that leaves exhale carbonic acid 
during the day, both in the sun and in the shade, and that the quantity increases in proportion to the 
temperature in which the plant is kept. 
To show the simultaneous occurrence of the two phenomena one branch of a living plant of 
* A Drummondii, n. sp .—Branches pilose, rigid, spreading; leaves scattered, or somewhat whorled, stalked, linear, acute at 
both ends, slightly scabrous above near the revolute margins, with a few hairs on the prominent nerves beneath ; pedicels shorter 
than calyx, in pairs or threes, from each axil; calyx pilose, the teeth nearly equal, those of the lower lip reflexed.—At. 
+ Outlines of Structural and Physiological Botany, \ 207. 
