196 THE ORCHID REVIEW. [Sept.-Oct., 1918. 
outer whorl uniting with the median petal to form the lip, and others 
becoming confluent with the styles to form a column, the nearest existing 
approach to the ancestral condition being the Apostasiz, in which the floral 
perianth is nearly regular, the column very short, the two, or occasionally 
three, anthers but little modified, the pollen grains free and simple, and the 
stigmas unmodified. The Apostasiez area small Malayan group, consisting 
of three genera and rather over a dozen species. 
The Cypripedieze may be regarded as a higher development of the same 
type. Here the lip has become slipper-shaped, the column further developed, 
the dorsal stamen dilated into a barren staminode, partly closing the basal 
opening of the lip, the anthers abbreviated, the pollen grains simple but 
coherent into a glutinous mass by means of a viscous modification of their 
outer coat, and the stigmas dilated into a convex body, with a granular 
surface. The flowers are fertilised by bees, which enter by the front opening 
of the lip, crawl past the stigma, and emerge by the basal openings, their 
backs becoming smeared during the process with the glutinous pollen, to be 
in turn left upon the stigma of the next flower visited. The group contains 
four genera and some eighty species, and is found in tropical Asia and 
America, with extensions right round the northern hemisphere. It marks 
the culminating development of the sub-order Diandre. 
The production of compound pollen grains and their union into pollinia, 
with the development of the rostellum, originated with the sub-order 
Monandre, which is characterised by having only a single fertile stamen. 
It was a concerted action by two distinct organs of the flower, the object 
being the economy of pollen, and the co-operation proved so succsssful that 
it has been continued and extended until the combined pollinary apparatus 
of the Vandee—half male, half female—which Bentham called the pollin- 
arium, has been reached. This concerted action has been so successful that 
the Monandre have attained an almost world-wide distribution, and now 
contains several thousand species, with a marvellously diversified structure: 
The pollinia proper are simply the combined pollinary contents of the 
anther cells with any developments they may assume, as for example the 
caudicles of Cattleya and others, which are composed of modified pollen 
grains. The pollinia vary in number, shape, and consistency in the 
different groups, according to the degree of development. In the simplest 
forms, as among the Neottiez, the pollinia are two in number, correspond- 
ing to the two cells of the anther, extremely friable, and without any trace 
of acaudicle. Somewhat higher, the pollinia are collected into little packets, 
these being attached by fine threads to a central axis, which terminates 
in a slender caudicle, and is ultimately attached to the viscid gland secreted 
by the rostellum. Among the Epidendree and Vandez the pollinia have 
become waxy,.and the number increased to four, six or eight, by division of 
