July, 1922] BAILEY — ■ POLLINATION OF MARCGRAVIA 
373 
by Seemann (1870), but are compound structures resulting from the fusion 
of a nectariferous bract and a sterile pedicel, is indicated, not only by 
their external morphology, but also by their internal anatomy. The fused 
pedicel shows as an embossed rib and terminates in a rudimentary flower 
bud, which occasionally develops into a normal flower (text figs. 3, 5). 
The fertile pedicels commonly are provided with corky excrescences. The 
outer surfaces of the adnate sterile pedicels are also conspicuously verrucose. 
Furthermore, as shown in figure 6, Plate XXIV, there are two distinct 
systems of fibro-vascular bundles in the nectaries, one belonging to the 
sterile pedicel and the other to the adnate bract. 
D u F 
Fig. 3. Marc gravia cuyuniensis spec. nov. /I. Pedicel and flower bud. 5. Pedicel and 
fruit. C. Pistil. D. Stamen. E, F. Nectariferous appendages; (a) rudimentary flower 
bud at apex of adnate pedicel. G. Abnormal appendage, showing adnate flowering pedicel. 
X i/i. Drawn from material preserved in formalin-alcohol by Miss Grace Griffin. 
Although there are traces of cohesion of floral members in Ruyschia, 
Souroubea, and Norantea, the flowers of Marcgravia are characterized by 
having calyptriform corollas. The petals are fused into a tough, leathery 
capsule or thalamus which entirely encloses the pistil and stamens (text 
fig. 4). This capsule does not split longitudinally at the time of "flower- 
ing," but becomes detached at its attenuated base. Delpino (1869) divided 
the genus Marcgravia into two subgenera: Orthothalamium, having the 
