BRYOPHYTE DIVISION, MOSSWORTS 531 
plicated expedients were adopted by plants akin, and the outcome 
is seen in such liverworts as Marchantia where small capsules are 
made to hang from the branches of vertical thallus-lobes, or in 
mosses like Sphagnum where a similar though erect capsule is borne 
on an even more elaborately developed vertical branch of the nurse- 
plant, which may live for many years. The most complicated ways 
of securing elevation are found in the mosses typified by Funaria, 
where both the nurse-plant and the spore-plant develop vertically 
as far as they can—the latter, as it were, standing upon the shoulders 
of the former—and by photosynthesis making food for the spores. 
But the utmost height attained by these methods is only a few 
inches; the foundation is weak. Growth which has to be accom- 
plished during a short season of moisture or by improving brief 
periods of wet weather, must naturally for the most part be limited 
to rather soft tissue and small organs. Mosses often grow crowded 
together like Sphagnum and thereby give mutual support and 
store a supply of water fer use in common; but although axes of 
considerable height may be buiit in this way, the offspring is not 
much benefited, for the crowded tops of the axes form virtually a 
new surface above which is the only height effective for scattering 
the spores. It is plain that effectiveness is not always favored by 
complexity. 
The view suggested above that mossworts have evolved directly 
from alge akin to Coleochete, although regarded as probable by 
many botanists, receives no support from the study of fossil plants; 
and is by no means the only view consistent with what is known of 
the plants of to-day. Thus, it is quite possible that our mossworts 
may be the more or less simplified descendants of larger plants 
widely different from any we know, which themselves were de- 
scended from seaweeds very unlike Colechete and of which we have 
now no trace. Not afew facts point to this conclusion; but the truth 
is we are much at a loss as to what to believe regarding the origin 
of mossworts, and the question seems likely to remain long a puzzle. 
Meanwhile, the hypothesis of direct’ algal origin may help us to 
imagine something of the nature of the problems which had to be 
faced by the earliest land-plants, whatever these plants may have 
been; and may suggest, at least by analogy, something of the means 
that may have proved most effective. 
When we remember that Bryophytes have had to depend almost 
entirely upon superficial moisture it is not a little remarkable how 
much they have been able to accomplish for the welfare of their 
offspring. In spite of serious difficulties attending the use on land 
of reproductive arrangements adapted to aquatic life, these little 
plants very commonly achieve the benefits of cross-fertilization, 
and of a considerable period of nursing for their young. All this is 
made possible by the formation of archegonia which not only pro- 
tect the protoplast of the egg, but by further development shield 
the young spore-plant all through its time of special tenderness. 
