March, 1935. 
The Queensland Naturalist. 
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0 / 
back sepals is referred to as the dorsal sepal, the side 
ones as the lateral sepals. They may be all very much 
alike, or the dorsal sepal may be markedly different from 
the lateral ones. The three inner members of the perianth 
are the petals, and a feature of practically all Orchids is 
that the lowermost one is very much modified in some way. 
It is generally lobed and differently coloured to other parts 
of the flower, and is called the labellum. The one excep- 
tion to this rule among Queensland Orchids is the genus 
Thelymitra, which contains the Sun Orchids. It is to the 
labellum that the distinctive beauty of some Orchids is 
due and this member is an extremely important one in 
Orchid classification, particularly in the differentiation of 
species. 
The family Orchidaceae or Orchid family is divided 
into a number of tribes and the tribes into genera, but 
before dealing with the classification 1 would just like to 
outline the main botanical features of the family. As re- 
gards habit, they are perennial plants either epiphytic or 
terrestrial. The term epiphytic, which comes from the 
Greek epi — upon, and Phyton — a plant, is perhaps not 
always applicable, because many of the epiphytic ones as 
commonly grow on rocks as they do on trees or other 
plants. Most of the terrestrial ones are tuberous, the 
tubers mostly being borne in pairs; hence the name 
Orchid. All the earlier Orchids known to botanists were 
of this type, for it may be mentioned that the members of 
the family are not confined to the tropics and subtropics of 
the world, but are moderately common in England, Con- 
tinental Europe and the temperate parts of the northern 
hemisphere generally. The Orchids of the British Isles 
number approximately forty distinct species or kinds, and 
when we come to countries such as France, larger and 
with a more diversified climate the number of Orchid 
species goes up to 75 or 80. The family is, of course, a 
huge one and contains more species or different kinds than 
any other family of flowering plants, the number of de- 
scribed species being somewhere about 20,000. The greatest 
number are found in countries such as New Guinea, 
Burma, Sumatra, the Malay States, and allied countries. 
Some of the more showy sorts come from the Upper 
Amazonian and Central American Region, but more num- 
erous kinds are known from the tropics of the Old World. 
In the epiphytic Orchids the stems are commonly 
creeping, the creeping part being known as the rhizome. 
The ascending stems may be swollen as in Bulbophyllum, 
Dendrobium and its allies, and are then referred to as 
pseudo-bulbs, from the Greek pseudos — false, and bolbos 
