182 President's Address. 



If the determinaLion is easy at first sight in the absence of 

 fruit, the facility is greatly increased when it is present. 

 Though occasionally in some genera the leaves when ex- 

 posed to the sun, especially wliere abundant moisture is 

 present, acquire red, brown, or other tints, they are by no 

 means so subject to assume abnormal tints as the Junger- 

 manniese. The earliest condition of Mosses is that of a green 

 mass of jointed threads, much resembhng Algse, which in 

 fact has been confounded with them ; this state is usually 

 called the protonema. Buds originate on parts of the 

 proton ema, and form by their growth the ascending axis ; 

 at tbe same time, radicular fibres strike downwards from 

 the bud. Soon after the true plant is formed, the pro- 

 tonema withers and disappears, having fulfilled its function 

 of supplying the young plant with nutritious fluids. In 

 tbe Ephemerae, however, which are plants of very rapid 

 growth, the protonema is persistent during the life of the 

 plant, which appears to nestle in it. 



Mosses are generally composed of the following parts : — 

 The stem, which is sometimes upright with roots at the 

 base, or is creeping and rooting at intervals. The struc- 

 ture is a cellular tissue without vessels, but indications of a 

 spiral deposit are seen in the cells of a few species. In 

 some cases the stem grows to the length of several inches 

 or even feet, while in Buxhaumia it is so reduced as to be 

 obsolete. The methods of branching are easily reducible 

 to two kinds in British plants, viz., Acrocarpi, or terminal 

 fruiting Mosses, which usually produce branches in pairs 

 below the flowers ; and Fkuroca-qn, or lateral fruit bearers, 

 in which the fruit is produced on a very short branch. 

 The ramification of pleurocarpous Mosses is very varied, 

 being either irregular, pinnate, bipinnate, fasciculate, or 

 dendroid, besides other modes which scarcely admit of a 

 verbal description. In addition to these two kinds, there 

 is another variety of fruiting called Cladocarpi. This 

 latter is sparingly found in Britain, but in tropical and 

 southern countries abounds and verges so completely into 

 the Pleurocarpi that it is impossible to draw a line of 

 demarcation. In acrocarpous Mosses the branch formed 

 under the inflorescence is frequently much elongated during 

 the growth of the fruit, and therefore the fruit seems to be 



