xil PREFACE. 
becomes contracted above the ovarium. The contrac- 
tion acts as a ligature, and actually presses into the fi- 
laments, though to ensure fecundation the upper fila- 
ments contract adhesions with the parietes of the calyx, 
the lower remain in the form of 5 subulate hypogynous 
processes, distinctly sphacelated at the apices. "These 
process are visible in the ripe fruit on opening the 
indurated base of the calyx. 
Chioranthacee.—To this order must be referred 
Houttuynia, the embryo of which is enclosed in a vi- 
tellus. It agrees with the order in every respect. The 
anatomy of the stem is decidedly dicotyledonous or 
rather exogenous. 
The small bractes underneath each flower have been 
overlooked, and likewise the fact that the terminal 
flower of each spike is sub 7-androus, and that it is 
surrounded by several, 2-3.androus male flowers. 
Thence Thunberg's uncertainty as to its real situation 
in the sexual system; which may either be, judging 
from the terminal flower Heptandria, or Polyandria, 
or with still greater propriety Moncecize. 
Piperacee.—The statement of the flowers of Pipe- 
racez being hermaphrodite admits of much doubt, 
some species are certainly unisexual. It is likewise to 
be doubted cime all — flowers are not uni- 
sexual. 
The structure. of the stem of Piper is certainly 
sd the fibro Maos and the fibrous, 
tia 
