ORCHIDS. 117 
species, Spiranthes australis, is at once separable from all others 
by the spiral arrangement of the flowers in its spike. Thelymitra, 
as stated before, is already remarkable for the almost complete 
conformity of the sixth sepal with the five others. Its name 
comes from the somewhat cap-like expansion of the column over 
the stigma (and anther). Calochilus unites in some measure 
most of the characters of Thelymitra with the papillar beautiful 
lip of Caladenia ; hence the name. Only one species and this 
sparingly, Calochilus campestris, is a native of Victoria. Well 
marked is Diuris, comprising our Dowbletail-Orchids, when the 
tail-like narrow lower sepals are contrasted with the rest, petal- 
like in form and color. There is only one other genus in Victoria, 
which in this respect could be confounded with Diuris, namely 
Orthoceras, but the two narrow outer sepals are turned upwards, 
suggestive of the name, forming horns; the only plant of the 
genus is Orthoceras strictum, narrow-leaved like all of Thelymitra, 
and Diuris. Perhaps the most common of all our Orchids is 
Microtis -porrifolia, it growing as well on pastures, as on heaths 
and in forests, even in deserts. The smallness of its green 
spicate flowers render it recognised at once, although a second 
and much rarer kind, M. minutiflora, exceeds it still in the 
extreme minuteness of its flowers. The specific expression of M. 
porrifolia refers to the cylindric and so far leek-like leaf; the 
generic appellation resorts to the minute appendages, by which 
the genital column is auriculated. To Microtis stands in close 
relation the genus Prasophyllum, literally translated: ‘“ Leek- 
leaf ;” the flowers are however turned upside down (resupinate), 
like in Orthoceras, Caleyana, Gastrodia and the following genus 
Cryptostylis ; both in Prasophyllum and Microtis the flowers are 
spicate or nearly so, though the longer ovaries of the former give 
them a racemose appearance (as if seated on stalklets). Real 
racemes occur in Thelymitra, Diuris, Dipodium, Gastrodia and 
rarely in Caladenia, the stems of the latter usually bearing only a 
single flower. Pterostylis includes species with racemes, spikes 
and solitary flowers. From any kind of ground of the lowlands up 
to the glacier-regions of the alps Prasophyllums may be found. 
Cryptostylis, though placed by structural affinity near to Praso- 
