ee 
18 ‘ 
for within the lower part of our bloom 
was a merry throng of tiny midge-flies, 
such as I have previously referred to, in 
the midst of a revel they dearly loved. 
The particular little midge that pat- 
ronises the arum in this country has no 
common name, but to distinguish it from 
other species of midge-flies I will give its 
entomological name, which is Psychoda 
phallznoides. The little insect is a near 
relative of the common gnat, and is 
familiar everywhere during the summer 
months. With wings closed it would 
about cover the space of a pin’s head, 
and it is very commonly seen hopping 
about in a curious jerky fashion on 
windows of outhouses and similar places, 
but it is very difficult to catch. Con- 
cerning the life history of the species 
very little is known, yet it is certain that 
when arums are blooming these midges 
give little time to anything besides 
drunken orgies within their shelter, You 
have only to cut open a bloom at the 
narrow neck portion and look down to 
the lower part to see ihe helpless insects 
lying in heaps, all more or less intoxi- 
cated--.intoxicated from over-indulgence 
in arum pollen, Indeed, they are often 
almost buried in the yellow dust, their 
hairy feelers, legs, wings, and bodies so 
thickly covered with it that the insect 
looks twice its natural size when it leaves 
the bloom. The temperature, too, inside 
the enclosed area where the flies are 
found is much above that of the external 
atmosphere, often from 10 to 20 degrees 
higher. e 
The arum’s scheme for entrapping thes 
little flies is a most artful one, and more 
like the ingenious work of a thinking 
animal than the blind instinct of a mind- 
less plant. ; 
In the first place, the arum bloom i 
not a flower, but what the botanist terms 
an inflorescence. That is to say, it is a 
WHITING & CO. 
DYERS, CLEANERS, & PRESSERS, 
268 Rundle Street East 
(‘Two Doors from Charlick Bros.) _ 
ALL KINDS OF WORK DONE, viz., 
Gents’ Suits thoroughly cleaned and pressed 
at 6s. 6d. ; dyed any color. 7s. 6d. oe 
Ladies’ Garments, all kinds, cleaned and 
pressed, 5s.; dyed, 7 Ser aes eel 
BA] Soi Weathers, Gloves, and 
» ~ tats Cleaned and Blocked. re 
French Cleaning a speciality, ‘ + 
All Repairs neatly and promptly executed. 
OORT 
«se 
We desire to say that we are prepared to 
guarantee our work equal to anything in 
jthe City, and to do all’ kinds of work sat 
Reasonable Prices. ; 
Give us a trial and prove us. * 
THE AUSTRALIAN GARDENER. 
branch of flowers; just as a shoot of fox- 
gloves would not be a flower, but an 
inflorescene, or branch of flowers. Now, 
I must here point out that a perfect or 
complete flower consists of four whorls— 
the green sepals, the colored petals, the 
stamens which produce the fertilizing 
pollen, and the central pistil, to the sur- 
face of which the pollen is conveyed in 
the process of fertilization. But a flower - 
need not necessarily possess all these 
parts; almost any whorl may be missing, 
However, the stamens and pistil are 
essential, although they need not always 
be in the same flower—i.e., one flower 
may have sepals, petals, and pistil. but no 
stamens, when it becomes a female flower. 
In such cases the pollen is generally con- 
veyed from one flower to another by 
means of insects that visit them alter- 
nately. The simplest and most primitive 
kitd of flower consists of a single pistil 
that produces a seed, or a single pollen- 
producing stamen, without any sepals or 
petals around it, and this is what we have 
in the case of the arum, The arum pos- 
sesses many flowers, botanically speaking, 
but it can scarcely be said to possess any- 
thing worthy of the name in its popular 
acceptation, although the inflorescence as 
a whole partly atones for its delinquencies, 
At the lower part of the purple club, 
in the area where the midges are en- 
trapped, there are three kinds of small 
bodies. Lowest of all are pale-colored 
roundish objects; each of these consists 
of a single pistil containing an embryo 
seed. Above these are some smaller, 
curious, purple-colored knobs which, when 
mature, burst open and shed quantities of 
yellow pollen dust. From what I have 
previously said, it is plain then that we 
have here two groups of the situplest. of 
flowers, just a single stamen, or a single 
‘pistil, without any other floral parts. 
Above these groups of ‘simple male and 
female flowers we find some other bodies 
shaped like the lower-female flowers, but 
from their surfaces appear long bristles 
which stand out away from the axis and 
‘point downwards. These objects are really 
‘female flowers modified to serve another 
purpose in the plant’s economy—aud of 
‘this more anon, “i Lael 
‘Now that we understand the various 
parts that constitute the yuaint floral 
structure of the arum, we may proceed to - 
see what connection they have with the 
tiny midyes that so love to visit them. 
_ The purple ‘club is the sign-post that 
attracts the midges, for ic is, of course, 
quite a conspicuous object as it stands 
against the pale green hood that encircles 
it, So presently the arum-seeking flies 
come along and espy the familiar’ sign- 
post. Nota moment is lost. They steer 
quickly for’ it “and ‘alight: upon it; and 
gleéfully descend ‘until they reach’ the 
narrow neck. portion, where they méet 
the bristly flowers. These latter, with . 
their bristles pointing downwards, prove 
dio obstacle to'the, midgés, so they ‘travel 
‘downtto the base of the flower, 
June 1, 1908 
Many of the midges have just come: 
from other arum blooms in the near 
neighborhood, and about their wings,. 
legs, and bodies they carry traces of their 
previous feastings in the form of minute 
pollen grains. But when they reach this. 
particular arum they meet with disap- 
pointment, for the arum contrives to 
induce the midges to enter the bloom 
well before its pollen is mature. So when 
the insects reach the base of the bloom 
and find no pollen there, they have plenty 
of time to sober down and, perhaps, 
repent the foolishness of their past orgy. 
In fact, this period of fasting after one 
feast often lasts so long that they beeome 
really hungry. Of course, you will ask : 
Why, then, do not the flies leave the 
bloom? They undoubtedly would if they 
could, and they travel up and down the 
central axis many times doubtless with 
with that intention ; bunt when they reach 
the bristles in the narrowed neck of the. 
bloom they find that, although they could 
travel down them freely enough yet thsy 
cannot return the same way, for the 
bristles point downwards and make a 
perfect barrier against their leaving. 
Indeed, they are priscners until the arum 
chooses to release them. There is often 
ample room for such tiny flies to travel 
up the sides of the hood, and so miss the 
bristles, but they make no attempt to. 
escape in this manner; it may be that 
the hood is too steep and smooth for them 
to climb. - : . 
So the midges crawl about within in 
durance vile and keep increasing in 
numbers as now Visitors arrive. Mean- 
while the lower female flowers arrive at 
maturity, and the top of each pistil 
develops a sticky stigma, Aniongst these 
guinmy surfaces the tiny flies wander in 
search of the pollen they need, and from 
theis legs and bodies are rubbed more or 
less every pollen grain that they brought 
with them from the arums they have. 
previously visited. And here lies the 
essence of the whole scheme. Hach pistil 
in this manner eventually gets cross- 
fertilized with pollen from a neighboring 
plant. Of course, the arum will eventuolly 
develop. pollen of its, own, but cross- 
fertilization results in stronger offrpring 
GEO. TAL, 
Veterinary Surgeon, © 
Horse Mouth Specialist, 
28 years Victorian ‘Practice. ~ 
au Tre hee 2 ; ale x 
OPERATIONS PERFORMED. 
ALL DISEASES TREATED. 
249 Rundle St., Adelaide. 
vo.) DE LEPHONE 1654.) 3 
