is now systematically regarded as merely a mo- 
dification of the tunicated bulb. The scaly bulb, 
though having an epidermis round each of its 
scales, possesses no coat or covering round its 
general mass, and is therefore called a naked 
bulb; and the other kinds of bulbs, whether con- 
sisting of concentric layers or of an apparently 
solid mass, are invested all round with a strong 
and fibrous membrane, and are therefore said to 
be clothed or tunicated. All bulbs propagate 
their species by forming offsets or young bulbs, 
which ultimately and spontaneously detach them- 
selves from the parent bulb, and become new and 
independent individuals. Some, as the crocus, 
perfect their offsets, and perish, in a single season ; 
and some, as the tulip and the hyacinth, perfect 
their offsets by slow degrees, produce them in a 
series of generations, and live through a long series 
of years. Some, when allowed to lie for years un- 
molested in the ground, accumulate their offsets 
above them, so as eventually to raise them above 
the soil; some accumulate their offsets below 
them, so as eventually to bury them at an un- 
congenial and perilous depth below the surface ; 
and most accumulate their offsets around them, 
so as eventually to form such a dense mass as to 
starve and choke one another into dwarfishness 
and decrepitude. Some offsets, as those of lilies 
and colchicums, are radical, or issue from the 
axil of the coats or scales, or from the surface of 
the radical plate; and some, as those of dentaria 
and bulbifera, are cauline, or issue from the axil 
of the leaves or umbels. The leaves of a bulbous 
plant are perfected at the apex, or receive their 
increments of growth at the base or in contact 
with the bulb; and the roots or radicles are 
perfected at the lower extremity, or acquire 
their increments of growth at their terminat- 
ing points. If, for example, a small piece of 
thread be passed through the leaf of a narcis- 
sus, it will be carried steadily upwards as the 
leaf elongates ; but if it be passed through a ra- 
dicle of the same plant, it will remain quite sta- 
tionary, even though the radicle should attain 
twentyfold the original length. Dr. A.T. Thom- 
son, who made a series of phytological experi- 
ments on this last topic in 1823, concludes, “ that 
the sap must be raised to the apex of the leaf, in 
order to undergo that change which is necessary 
to render it, on descending, fit to be assimilated 
into the substance of the, bulb, and that it is from 
this altered sap that the increase to the leaf is 
derived ; or, in other words, that the apex of the 
leaf, in bulbiferous plants, performs the same func- 
tion as the entire leaf in trees and shrubs.” 
The economy of bulbs, while evidently of great 
interest, has been the subject of much conflicting 
and obscure discussion among phytologists ; and, 
in some respects, continues to be badly or not at 
all understood by the great majority of culti- 
vators. Buta recent report of some experiments 
and observations by the Italian naturalist, Dr. 
Augustus Trinchinetti, places this topic in a 
BULB. 
comparatively clear light, and dissipates much 
of the obscurity in which it was formerly in- 
volved. The bulb of Crocus sativus was selected 
as the subject of Dr. Trinchinetti’s immediate 
experiments, and treated by him as a fair speci- 
men of the whole great family of bulbs. This 
bulb, as examined in its dormant state, is com- 
posed of a parenchymatous starchy substance, 
and consists of a flattish, globular, central body, 
and of dry, loosely-fibred coats, succeeding one 
another like a series of scales, and forming a se- 
ries of mutually enclosed and gradually larger 
membranous funnels, easily separable from one 
another, but all attached at their base. When 
the funnels are artificially removed, a solid whit- 
ish bulb is observed within them, somewhat com- 
pressed in the upper part, and marked horizon- 
tally with circular lines indicative of the bases 
of the removed funnels or coats. Near the centre 
of this inner bulb, or in the middle of the upper 
part of it, are three or sometimes more cones, 
formed of finer funnel-shaped coats, under each 
of which appears, in the form of a small tubercle, 
the germ of the offset or new bud destined for 
development in the next growth; and all over the 
bulb, without any regularity of distribution, are 
various marks, of different sizes, formed of very 
fine coats, and containing small germs, which are 
destined for development according to the health- 
iness and secretionary power of the parent bulb, 
and which may, in some instances, become abor- | 
tive when the parent bulb is too small or too 
feeble to afford them requisite support. When 
the bulb is cut asunder in its dormant state, it | 
presents to view only a homogeneous milk-white | 
mass, without any apparent organization. When 
it begins to vegetate, it sends out circumferential 
fibrous roots, and developes one or more germs, 
which increase into one or more little bundles, 
each formed of a sheath with enclosed leaves, and 
the largest containing also the flower. A slight 
expansion appears at the base of the little bun- 
dles; and this, when cut through lengthwise, dis- 
covers a smaller bulb, surrounded by coats, the 
exterior ones proceeding from the sheaths, the 
interior ones from the leaves, and both combined 
forming a small solid substance. 
“Tf,” says Dr. Trinchinetti, “when the vege- 
tation has considerably advanced (say about a 
month after flowering), these small bulbs are 
again cut through, and a part of the large bulb 
from which they spring is included in the sec- 
tion, the portion where the coats terminate will 
be found very much increased in size, and also 
divided into two parts of different substances; 
one of which, the germ, is almost of a conical 
figure, with its base uppermost; it has, in its 
centre, one or more tubercles; and its point, 
penetrating downwards, terminates towards the 
centre of the old bulb, where it joins a similar 
part proceeding from each of the offsets, and 
whence the circumferéntial roots have their 
origin. This germ is of a yellowish colour and 
