Holloway. — Studies in the Neir Zealand Species of Lycopodium. 89 



which shows that the main tissue of the leaf at the point of attachment is 

 undisturbed. The bud from the first is vividly green, and is usually crowded 

 with minute starch-grains. Its central cells appear brownish and opaque, 

 owing to their dense protoplasmic contents. The first protophyll arises 

 simply by the continued growth of the buds (figs. 15 and 18, and Plate IX, 

 fig. 1). A second protophyll and then a third arises from the first-formed 

 bulbous portion alongside the first (fig. 19). By this time the young plant 

 has become well attached to the underlying humus by means of its rhizoids, 

 and the parent leaf is beginning to rot away. In one instance a plantlet 

 which had originated adventitiously from the cortex of an old detached 

 root, to which it was still attached, had developed a very young bud near 

 the apex of its single protophyll. Both protophyll and bud were packed 

 with starch-grains, and a single rhizoid had developed about half-way up 

 the protophyll from one of its epidermal cells. Plate IX, fig. 2, shows a 

 well-grown bulbil developed upon a second adventitiously produced plantlet. 

 A second example of a rhizoid being formed on an old leaf which bore a 

 young adventitious plant was also observed, the leaf in this case beiny 

 detached. 



The parent leaf is generally greenish in its upper portion but colourless 

 below, and is always obviously broken off at the lower extremity. The 

 leaves shown in figs. 19 and 20 had each developed two swollen areas in 

 their lower portions. These bulbous places on the leaves were of much 

 the same appearance as the first-formed swollen portion of the developing 

 bud, the central cells being brownish and opaque owing to their abundant 

 protoplasmic contents. A group of rhizoids was present on each of these 

 swollen areas. In many cases it was noticed that the rhizoids arising from 

 the developing buds, and also the cells of the lower portion of their proto- 

 phylls, and especially the cells of the basal bulbous regions, were crowded 

 with starch-grains. Some of the parent leaves also, including the two in 

 which swollen areas had formed, showed the presence of starch in their 

 lower portions. A single instance of a branched leaf was found (Plate IX, 

 fig. 3). Two branches had arisen upon the parent leaf, but on neither 

 of these were rhizoids present, nor were their bases swollen. They had 

 evidently developed somewhat differently from a bulbil. 



Fungal hyphae do not seem to be present in the cells either of the parent 

 leaf or parent root of the plantlets. The transverse section of the base of 

 an adventitiously produced bulbil of L. cernuum, shown in fig. 4, is closely 

 similar to sections of plantlets of L. ramulosum which had developed from 

 detached roots and from leaves. The central cells of the lower bulbous 

 portion of the plantlet contains abundant protoplasm and also numerous 

 minute starch-grains. As the plantlet develops, these cells become narrow 

 and elongated, and seem to function both as a storage and as a conducting 

 tissue. A distinct epidermal layer of small-sized cells is differentiated from 

 which rhizoids arise, whilst the cells in the zone which lies between the 

 epidermal layer and the centrally placed cells gradually assume in the 

 developing plantlet a large size, and are then for the most part empty. It 

 is clear that the core of slightly elongated parenchymatous cells in the 

 young plantlets is not to be regarded as the primordium of the permanent 

 stem vascular cylinder. That, of course, arises, as in the case of the sexu- 

 ally produced plants of L. cernuum, L. laterale, and L. ramulosum, in the 

 first place by the extension of the protophyll-strands down into the tissues 

 of the plant, and their aggregation there, and secondly by the development 

 of a plerome from the meristematic tissue at the stem-apex. 



