112 PRINCIPLES OF BOTANY, ETC. 
2. Articulated, (articulatum), when the transverse 
partitions appear distinctly on the outside, and are 
easily divided into joints, as in Hedysarum. 
3. Intercepted with isthmuses, (ésthmis interceptum), — 
when_the transverse partitions are easily seen, and 
also easily separate, but the cells are much smaller 
than the articulations, as in Hippocrepis. 
GT 
The case, (theca), is the fruit of the frondose 
Musci. It is a dry fruit that opens in the middle 
with a lid, and is furnished with particular parts. 
A. The Calyptre, (calyptra), 1s a tender skin 
that like a cup loosely covers the top of the 
theca. (S)-79). 0 Altiis, 
1. Intire, (integra), that wholly covers the top of 
the theca, as in Grimmia extinctoria. 
2. Halt, (dimidiata), that only half covers the top 
of the theca, as in most Musci, fig. 138. : 
3. Hairy, (wilfosa), that 1s composed of hairs, as 
in Polytrichum, fig. 136. | 
4, Dentated, (dentata), when the rim is set with 
teeth, as in Grimmia denéata. 
B. The Lid, (operculum), is a round body that 
closes the opening of the theca, and when the 
seed is ripe falls off. It is, 
1, Convex, (convexum), that has a raised or arch- 
ed surface. | 
2. Conical, (conicum), that is wide below,’ but 
runs above into a round point. 
3. Acute, (acutum), that is wide below, but above 
erows gradually into an acute point, fig. 138. 
4, AcuU-., 
