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through. There are many species, called Green Hood, 

 Helmet, Cow Horns, &c., all formed on one type. 



Cow Horns is very common in the spring. The flowers 

 are solitary and nodding at the end of slender stalks. 

 Green and brown and rather flattened laterally, it is made 

 up of six segments of two series of three each, which it 

 will be convenient to call calyx and corolla. It appears 

 to be formed of two parts, an upper hood and a lower 

 erect portion. The hood consists of one sepal and two 

 petals, not united but adherent. The lower piece consists 

 of two sepals which have slender terminations and rise up 

 on each side of the hood. The third petal is a very peculiar 

 structure, and as it is greatly altered from a petaloid form 

 in Orchids, it is called the labellum. Labellum means lip. 

 In Pterostylis it looks more like a tongue, which varies 

 slightly in shape in different species. In Cow Horns the 

 labellum is long, slender, dark, nearly erect, the acute 

 tip protruding through the division between the two lower 

 sepals. It is supported upon a flat curved stalk, and from 

 its base arises a small curved lobe tipped with an irregular 

 brush. 



The column is bent to accommodate itself to its position 

 within the hood, and has on its anterior surface a fleshy 

 stigma, and close above at the apex are two anthers con- 

 taining pollen masses; along the upper third are the two 

 delicate wings already alluded to. A fly attracted to this 

 flower enters through the opening between the perianth 

 segments, and alights upon the tip of the labellum, down 

 which it walks towards the stigma. As soon as it touches 

 the brush, by a peculiar faculty the labellum moves, plac- 

 ing itself close against the opening between the wings, 

 where it remains for some time. The fly then proceeds to 

 escape. The way it entered is shut off by the new position 

 assumed by the irritable labellum; it therefore proceeds 

 up the column between the wings, comes in contact with 

 the anthers, the discs adhering to it, and flies away with 

 pollen masses attached. Being a greedy animal, it enters 

 another flower, and exits in a similar manner, only in 

 passing the stigma it rubs the pollen on the sticky surface. 

 As the fly always goes the easiest way, the pollen is never 

 placed on the stigma of its own flower. We have many 

 species of Pterostylis, but the flowers all conform to this 

 type. 



Spider and Pink Orchid are dissimilar flowers of one 

 genus, Caladenia The perianth segments in Spider are 

 very long ; in Pink Orchid they are short. The three sepals 



