130 THE ORCHID REVIEW. [May, 1909. 
divided into two families or Natural Orders, Burmanniacez and Orchidacee, 
the former with regular or actinomorphic flowers, and seeds containing 
endosperm, the latter with the flowers irregular or zygomorphic, and the 
seeds without endosperm. The latter is by far the larger and more highly 
specialised. 
The most primitive of existing Orchids is the genus Neuwiedia, contain- 
ing some half-dozen species, two of which flowered at Kew a few yearsago, 
‘and were figured in the Botanical Magazine, N. Lindleyi (t. 7368), with 
yellow flowers, and N. Griffithii (t.7425), with white flowers. At the first 
glance they scarcely look like Orchids at all, on account of the free stamens 
and linear anthers, but they have all the essential characters of the Order, 
‘and in fact Neuwiedia with two other small genera, Apostasia and Adactylus, 
form the small tribe Apostasiee. It is true that some authors have 
considered them a distinct Natural Order, but if this view were accepted it 
would be necessary to make the Cypripediez another distinct Order, it 
being much nearer to Apostasiezw than to the great Orchidaceous suborder 
Monandre. In point of fact Apostasiez is a tribe of ancestral Orchids. | 
The primary division of the Orchidacez is into the suborders Diandrz 
(sometimes called Pleonandrx) and Monandre, the former having two or 
three perfect anthers, and the latter normally only one. There are other 
essential differences. For example, in the Diandre the pollen grains are 
not aggregated into pollinia as in the Monandre, nor is there a rostellum. 
The rostellum is a later adaptation, and its function is to secrete a viscus 
by which the pollinia are secured to the bodies of the insects which fertilise 
the flowers. 
The suborder Diandre is divided into two tribes, Apostasiez and 
Cypripediee, the former having a three-celled ovary, a nearly regular 
perianth with subequal segments, two or three more or less elongated 
anthers, the pollen dry, and the style slender, straight, with a minute three- 
lobed stigma ; while in the latter the perianth is irregular, with very unequal 
segments, one of them, the lip, developed as a pouch-like organ, the anthers 
globose, the pollen grains cohering into a sticky mass, and the stigma 
dilated and shield-shaped, while above it is situated a second shield-shaped 
body, called the staminode. The ovary may be either three-celled, as in 
Apostasiez, or one-celled, as in Monandre. 
It is very interesting and instructive to compare the structure of 
Neuwiedia with such a complex flower as Stanhopea, but equally difficult to 
understand the relationship of some of the parts without tracing the 
successive steps by which this high degree of specialisation has been 
reached, and to this point the present article is largely devoted. - It is only 
in this way that we can hope to understand the numerous beautiful 
adaptations which are met with in the Order. 
