The stems of most mosses are made up of a succession of similar parts, 

 the annual growths, and are separable or transversely breakable at certain 

 points, more especially at the points where one season's growth ends and 

 the next begins. When a part is detached and is carried to a favorable spot, 

 it commences its growth by producing rhizoids, which serve the double pur- 

 pose of fastening it to a substratum and of assisting in its nourishment. 

 The part may now continue its growth and develop into a plant, or it may 

 produce protonemata with vegetative buds directly, or by the intervention 

 of rhizoids. Branches, when detached from their stems, usually reproduce 

 the plant in the same manner as stems. They are, however, in some species, 

 as Campylopus flexuosiis, provided with special means for vegetative repro- 

 duction. At a certain point, usually near ite distal end, the branch is so 

 weakened by a cleavage in its walls (Trennschicht), that the terminal por- 

 tion is readily shed. When detached, these end branches (Endknospen) 

 grow into plants in the manner already detailed. In structure and devel- 

 opment they are closely related to bulbils. When a leaf of a moss plant is 

 detached from its stem (which often happens as the result of mechanical 

 action or of a process of fatty degeneration of its insertion cells, as in 

 Dicranum scoparium) and finds a favorable lodgment, it reproduces the 

 parent plant as stated when reference was made t.o Heald's experiments, 

 more rarely by vegetative buds directly from its surface. In some species, as 

 Dicranum viride and Anomodon trisiis, the leaves are transversely breaka- 

 ble by a line of weakened cell cohesion, the detached or broken parts repro- 

 ducing the plant as is done by the whole leaf. 



The adventitious formations which serve to propagate asexually the 

 moss plants are of two kinds, bulbils, sometimes called gammae, and brood 

 bodies, sometimes called propagula. In their simplest form, bulbils are lit- 

 tle buds without apparent central axes, and usually appear on the stem, as 

 in Webera annotina, but may be located on any part of the moss plant. 

 When shed, sometimes even before, they produce rhizoids and grow directly 

 into the vegetative plant. In their higher development, with rudimentary 

 stems and leaves, they appear in bud-like aggregations on the end of stems, 

 as in Leskea iier.vosa, sometimes on branches as well. In their highest 

 development, their character as shoots becomes apparent, with stems and 

 leaves, as in Dicranum flagellare, growing into plants, however, in pre- 

 cisely the same manner as is done by the simplest forms. 



Brood bodies are polymorphous and variously located. In their sim- 

 plest form they are deciduous rhizo-protonemata which appear in clusters on 

 stems, often on midveins, as in Plagiothecium Roeseamim. They are, how- 

 ever, usually more complex in structure, and are sometimes borne on spe- 

 cialized stems and branches, the pseudopodia, as in A u lacomniltm palustre : 

 or in a cup-shaped involucre, as in Georgia pellucida; or on rhizoids (Brut- 

 knollen), as in some of the Barbulae; or on the excurrent costa, as in Ulota 

 phyllantha; or on the paraphyses. as in Pottia riparia; or on the upper 

 surface of leaves, as in Tor tula papulosa; or on both surfaces, as in Ortho- 

 trichum Lyellii: or in fasciculate clusters on the midrib at the base of the 

 leaves, as in Grimmia torquata. In whatever form or position they appear, 

 their function is the same, the reproduction of the parent plant, which they 

 accomplish by producing protonemata. 



