THE FLORAL DEVELOPMENT AND EMBRYOGENY OF 
ERIOCAULON SEPTANGULARE 
R. WILSON SMITH 
(WITH PLATES XIX AND XX) 
Flowers 
The inflorescence of Eriocaulon septangulare is a compact head of 
Staminate and pistillate flowers. The two kinds of flowers are 
sometimes intermingled, but the most common arrangement is in 
groups of 10-30, all the members of each group exhibiting nearly 
the same stage of development. During the season there are usually 
about three successive groups of each kind of flower. 
Longitudinal sections of the flower show that the parts appear 
in acropetal succession. ‘The two sepals, and likewise the two petals, 
arise from the floral axis at somewhat different levels. This is 
probably to be interpreted, not as the survival of a primitive spiral 
arrangement, but as a result of the intercalary growth which is a 
marked feature especially of the inner flowers (fig. 5). Rudimentary 
carpels surrounding the tips of the floral axis occupy the center of 
the staminate flower (jig. 1), but do not progress beyond the stage 
Shown in the figure; they can still be recognized readily in the old 
flowers. In the pistillate flowers the stamens are represented by 
rudimentary outgrowths put out above the petals and having their 
€xtremities of withered and blackened cells (fig. 2). Each flower is 
subtended by a bract and bears large conspicuous nectaries upon 
the petals. Transverse sections are shown in jigs. 3 and 4. Fig. 36 
and corresponding sections of the pistillate flowers show that the 
Stamens belong to one cycle, and hence the flowers are tetracyclic. 
The manuals describe this and other species of Eriocaulon as 
having the parts of the flowers in twos and threes, but in and about 
Lake J oseph, Ontario, where this material was collected, I have 
been able to find only the former type of flowers. Do these constitute 
@ local race, or will other localities furnish similar examples of the 
Constancy of dimerous symmetry ? 
281] [Botanical Gazette, vol. 49 
