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SOME FACTS ABOUT ARUMS. 
The true flowers are set round the base of this central 
column, what we call the blossom being in fact an assemblage 
of many blossoms, some of which are barren and some fertile. 
The fertile flowers bear pistils, and the barren stamens ; and 
it is from the former, which are usually set lowest on the 
spadix, that the clusters of fruit are formed. 
If the green sheath of the wild spotted arum or cuckoo- 
pint be wrapped in and filled with wadding to prevent the 
escape of the heat, the mercury in a thermometer placed close 
to the brown column will be found to rise several degrees. 
The sudden increase of heat is more remarkable still in 
the lieart-leaved arum of the Isle of Bourbon, whose temper¬ 
ature at blossoming time rises from twenty to twenty-four 
degrees centigrade above that of the surrounding air ; and 
even this is outdone by the common Italian arum, which 
grows in the olive-yards, and is a familiar object to all who 
have enjoyed a Roman spring or spent a winter in the 
Riviera. This plant much resembles the cuckoo-pint, but 
its glossy dark leaves are larger and veined with yellow. 
The pale yellow sheath, which is stalkless, grows close to the 
ground, unfolds in March and April between 4 and 6 p.m., 
and emits a fragrant odour like that of wine, the temperature 
of the club-like column at the same time rising until it feels 
quite hot to the touch. 
Professor Kraus found four of these arums near Rome 
one 28tli of March, the temperature of whose blossoms 
varied from 40°C. to 43-7°C., that of the surrounding air 
being at the time 16 Q C. ; 20°C. (68°F.) is a good summer 
heat, and 35°C. is blood heat, but these arum blossoms were 
hotter than a hot bath. This state of things did not last 
long, however, and by the following morning the sheaths had 
grown pale and wrinkled, the blossoms had passed their 
prime, and the heat had quite disappeared. 
Interesting as these facts are in themselves, they become 
still more so when we consider them a little further, and ask 
what they mean. The older botanists, Humboldt included, 
had noticed the extraordinary degree of heat generated by 
some of the arum family, but there they stopped short, and 
the Italian, Delpino, seems to have been the first to suggest 
a reason for the phenomenon. 
It is well known that in order to produce perfect seeds, 
most plants require to be fertilised by pollen brought from 
other plants of the same species. For this they are dependent 
upon wind, rain, birds, insects, &c., the two last mentioned 
being attracted to them by their bright colours or sweet 
scents. 
