272 
Recently I had occasion to investigate the fruit characters of 
this Opulaster and find that the carpels do rupture along well-de- 
fined sutures, although it takes place tardily. The fruit of the 
species is usually 2-carpellary, very rarely 3-carpellary. Each carpel 
is from 1—3-ovuled, developing as many or fewer seeds; the usual 
number is I or 2. At maturity’the carpel is nearly triangular, 
much flattened, not at all inflated, and when well developed 
it measures about 4.5 mm. in length, and 3.5 mm. in width across 
the broadest portion. The seeds are oblong, somewhat com- 
pressed, nearly 2 mm. long and 1.3 mm. wide, grayish in color, 
with a firm polished testa and extremely bitter taste. The two 
carpels seen together bear a great deal of resemblance to the 
silicle of a Lepidium as Prof. Greene notes. 
The carpels are connate except at the divergent apices. They 
usually separate along a lateral line at maturity. Occasionally 
this line of demarcation does not form and they remain united. 
The pedicels commonly fall away from the axis of inflorescence 
in autumn or early winter by the development of a constriction at 
their bases, carrying the unopened fruit with them. The dehis- 
cence of the carpels does not usually occur until after they reach the 
ground, but if the pedicels are not detached from the axis of the 
corymb in the fall, which sometimes happens, the carpels will 
rupture in the spring while retaining their original position and 
enfolded by the persistent calyx. 
The dehiscence of the carpels takes place along two sutures, a 
ventral and a dorsal. In the majority of the cases that have come 
under my observation the inner or ventral suture opens first, the 
fissure beginning near the apex or at the point of juncture of the 
carpels, and is complete from base to summit. The outer or dorsal 
suture opens immediately after the rupture of the inner, but the 
line of dehiscence extends across the top of the carpel only. 
Owing to this circumstance the carpel is never two-valved in de- 
hisence, apparently a new character in our North American 
Opulasters, and therefore, clearly, to be considered as follicular. 
When the carpels are so firmly united that no lateral separation 
between them takes place the inner suture opens through both 
simultaneously. Joun B. LEIBERG. 
Hope, IDAHO, March gth, 1895. 
