401 
A rum maculatum from the Seed. 
vegetatively produced plant is as long as the distance from 
the upper part of the tuber to the surface of the ground, and 
as the tuber of the mature plant is situated from 10-16 cms. 
deep, the difference in length between this and the seedling 
petiole is very material. 
In a favourable habitat the majority of the new plants are 
produced vegetatively, for the Arum is a plant in which the 
individual becomes very well established, and is to a great 
extent independent of reproducing itself by seeds. 
It will now be necessary to give a more detailed account 
of the germination of the seed. 
The work in this part of the subject has been necessarily 
slow and laborious, as the material had to be collected at 
intervals of a month or less for four seasons. 
The seed first swells considerably, then the cotyledon 
emerges from the seed-coats, carrying with it the plumule 
and radicle (see Fig. 1). Even at this stage, reached in 
January, the hypocotyl below the plumule is enlarged to 
form the tuber, and is packed with food-material. 
The stem-bud, which is situated on the tuber and within 
the hollow cylindrical cotyledon, consists of two leaves, one 
quite rudimentary, and a growing point. 
In the next stage, represented in Fig. 3, April, 1896, both 
radicle and cotyledon have elongated, and the tuber has 
doubled its diameter ; within the stem-bud a new leaf has 
appeared, and the bud now contains all the leaves, which will 
reach maturity during the third season. 
In Fig. 4, May, 1896, a rudiment of a fourth leaf, which 
will not be fully developed until the fourth season, appears. 
In Fig. 5, June, 1896, the radicle shrivels and soon entirely 
disappears. Shortly before this the cotyledon, carrying the 
seed-coats with it, has been detached from the tuber, leaving 
the stem-bud exposed. This process is brought about by 
the formation of periderm l . 
Up to the stage shown in Fig 4 the tuber is covered by 
1 Cf. Parkin, On some points in the Histology of Monocotyledons, Ann. of Bot. 
June, 1898. 
