July, 1922] BAILEY — POLLINATION OF MARCGRAVIA 
and pollination of these interesting plants. Before discussing the results 
of this investigation, however, it is essential to outline certain salient 
morphological features of the Marcgraviaceae. 
Salient Features in the Morphology of the Marcgraviaceae 
As shown by Jussieu (1809), Delpino (1869), Wittmack (1878), Szys- 
zylowicz (1895), and others, the small neotropical family Marcgraviaceae 
is characterized by having nectariferous appendages which are closely 
associated with the flowers. These nectaries vary considerably in size, 
shape, and structure in different species and genera, and are significant 
in the classification of the various representatives of the family (text fig. i). 
In the genera Caracasia and Ruyschia, they are small spherical or hemi- 
spherical organs which are attached to the pedicels of the flowers, as are 
the more or less deeply concaved and spurred nectaries of Souroubea. 
In Marcgravia, on the contrary, they are relatively large sac-shaped or 
galeate structures which are inserted upon the apex of the peduncle. 
There has been considerable speculation concerning the origin and 
morphological significance of these nectariferous appendages. Are they 
metamorphosed bracteoles, abnormal pedicels, modified bracts, or append- 
ages sui generis? Most recent students of the Marcgraviaceae have ac- 
cepted Planchon and Triana's (1863) conclusion that they are evaginated 
bracts. It must be admitted that there is considerable evidence in favor 
of this view. 
The leaves of the Marcgraviaceae are provided with hypophyllous 
excretory organs which vary considerably in size, number, and distribution 
in different representatives of the family. Two of these glands tend to 
be located at the base of the lamina, one on either side of the midrib. In 
small, rudimentary leaves, such as commonly occur near floral axes, these 
basal glands become proportionately accentuated as the lamina is reduced 
in area. Interesting transitions between rudimentary glandular leavcs of 
this type and spoon-shaped, hooded, or sac-shaped nectaries occur in 
various Marcgraviaceae; and are particularly numerous and conspicuous 
in Norantea, e.g., N. anomala H.B.K. and N. hrasiliensis Choisy. In cer- 
tain specimens, the nectariferous bracts at the base of the inflorescence 
resemble rudimentary leaves and are attached to the peduncle just below 
the points of insertion of the pedicels, but in the middle and upper portions 
of the racemes they become more and more deeply concaved or evaginated, 
and their petioles fuse with, and therefore appear to arise from, the pedicels 
of the flowers. The concave or inner surface of the nectariferous append- 
ages is the morphological equivalent of the under surface of the leaves. 
The outlets or pores of the hypophyllous glands are located in this dorsal 
surface (PI. XXIII, fig. 2) and, accordingly, discharge their sugary ex- 
cretions into the concavities of the bracts (PI. XXIV, fig. 9). 
In the more or less elongated, usually erect, racemes of Ruyschia, 
