New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1875-08-20
NEW PUBLICATIONS..
pAnwry's INsECrrvoRoUs PLANTS.


The researches of Mr.. Darwin which have resulted
n the discovery of exceptional properties III cer'"
plants confirming the fact previously observed that
soutrary to received traditions they possess car
sivorous nature, were commenced in the Summer of
1890. Upon examining the leaves of the common
sundew, or drosera, he was surprised to iind
large number of insects entangled in their hairs, OF
tentsclcs He gathered by chance a dozen plants,
bearing ffty-sx fully expanded leaves TO thrty-one
of which were attached the remains of dead insects
On one plant all six leaves had caught Their prey
and on several plants many leaves had caught more
than a single insect On one large leai, there
were the remains of thirteen distnct insects Vi
these flies were the most numerous. Inc hfees.
Kind observed by MIR. Darwin himself was small
butterfly, but he has been informed of the capture
of n large living dragon-hy, with its body hriniy
held by two leaves
The plant ldroseral which was the subject OF MS
Investigations hears from two or three to ve OF SIN
leaves generally extended more or less horzoh'alS'
INIT sometimes standing vertically upwards. The
whole upper surface is covered with giaao-Deatn's
f,aments, or tontacles so called from their manner
of acting. The average number OF glands on 'hirty
one leaves. many of which however, were OF unu-
sually large size was 1872, the greatest number De
ing goo and the least 100. The glands are each
surrounded by large drops of extremely vscld seere
tion which glittsrng in the sum- have given 11se 10
the plants poetieal name of sundew. a tentacie
consists of thin straight hair-like pedicel carry
ing gland on the summit. The pedicel is 1orihed
of several rows of elongated cells, filed with purple
fluid or granular matter. There Is a mario"
zone close beneath the glands OF the longer
tentacles and a broader zone near lher
bases of green tint. Spiral vessels, ac-
romoanicd BIZ simple vascular tissue, branch OF iro
the vascular bundles in the blade OF the leai' ana
run up all the tontaclcs into the glands Inc 'ent
cles on the central part Of the leaf are snort ana
stand upright and their pedicclsare green. Towards
the margin they become longer and longer and more
inclined outwards with their pedicels of purple
color. The glands with thc exception of those
horne by the extreme marginal tentaclcs, are oval
and OF about 400 of an inch in length They consist
of an outer laver of small polygonal cells contain
ing puIple granular matter or fluid. Within THE
Iayer of cells there is inner one Of differently
SHAPED ones likewise filed with purple fluid, but oil
slightly different TINT The purple fluid OF grair-
lar matter which fills the cells of the glands differs
10 certain extent from that within the cells OF the
pcdicels.
The action Of the several parts of the plant in the
capture Of an insect may be briefly described as FOL
lows: II small object be placed on the glands III
fhe center of leaf these transmit impulse to the
fecte and slowly bend towards the center, and then
those further off until AZ last all become closely in
Elected over the object. This takes place in from one
hour to four OF FIVE OF more hours. Tie difference
In the time required depends on many ciTcums ances
n the size and nature Of the object that is, whether
Ii contains soluble matter of the proper KIND the
vigor and age of the leaf and as seems most prob
able on the temperature of the day. a living IN
sect is more efficient object than dead one, as IN
struagng il presses against the glands Of many len
tacles An insect like the fly, with thin lntegu-
ments through which animal matter in solution can
readily pass into the surrounding dense SECRETION Is
more efficient in causing prolonged infection than
nm insect with thick coat such as the beetle. The
infection of the tcntaces takes place indifferently
in the light and darkness and the plant Is not sub
iect tn anv nocturnal movement of so-caled sleep
If the glands on the disk repeatedly touched or
lrnsheJ although no object is left on them the mar
cinal tentacles inwards. If drops OF various
fluid. are placed the central glands, the same re-
suit quickly follows. Avery minute particle of any
rubStapce such as bit of thread or hair OF splin
fer of glass If placed in actual contact with the sur
face of gland will sufice to cause the tentace TO
bend Not only the tentacleS, but the blade of the
leaf often but by means always, becomes much
incurred, when any strongly exciting substance Is
nlaced ON the disk Drops of milk ard of solution
effect The blade is thus converted into little cup.
The secretion from the glands is extremely viscid,
90 that il can he drawn out into long threads. Ii
appears eol0rless but stains little balls Of paper pale
mink When a bit of meat, or insect, is placed on
the disk of leaf as soon us the surrounding ten
tacles become considerably infected their glands
pour forth an increased amount of secretion This
not only increases in quantity, but changes its
ture and becomes acid, before the glands have
touched the object on the center of the leaf. The
secretion seems possess like the gastric juice Of
The higher animals, antiscptie power. As soon
as the tentacles which have remained closely in
Geeted during several days over an object begin to
resxpand their glands secrete less freely,
secrcte and are left dry. After the reexpansiOn is
complete the glands quickly begin To rosecrete and
as soon as full-szed drops are formed the entacles
are ready TO clasp new object
When an insect ahghts or the central disk, it Is
Instantly entanglcd by the viscid secretion, and the
surrounding tentaces begin to bend and ultimately
clasp il on all sides. Insects generally killed in
about a quarter Of an hour, owing 10 their tracheI
being closed by the secretion. III insect adheres
10 ONLY few Of the glands of the exterior tenta
cles these soon become infected and carry their
prey to the tontacles next succeeding inwar's
which then bend i,wards and so on until the insect
il horne by sort OF rolling movement TO the center
of the leaf After a brief interval, the tentacles
all sides then become infected and battle their prey
with their secretion the manner If the in
seet had first alighted on the central disk.
The question: Of course arises whether the plant
can only absorb matter already in solution, or
whether ii is able to render il soluble that is pos
sesses the power of digestion. This most wonder
full fact in the physiology of pantsis clearly proved
The leaves of droseTa act OF albuminous compounds
in exactly the same manner as the gastric jace OF
mammals, the digestcd matters being afterwaId ab-
CORDED Nj. Darwins experiments included great
xar,etr of alhnmirone snbstances lut the result IN