of the shoot divides, anchors itself firmly by means of the comb- 

 leaf, takes root and grows into a new plant." 



A. Kerner, in his Natiu^al History of Plants, ii., 807 

 (English ed. 1895) says : — 'Towards the close of the winter the 

 end of the stem above the leaves is seen to become peculiarly 

 modified. Its internodes become much contracted, and at the 

 lowest node is developed a scale-leaf with 4 lobes, which sur- 

 rounds the leaves developed from the upper nodes, like a cup. 

 Buds arise in the axils of one or two of these leaves, while the 

 leaves themselves die and decay. The parenchyma of the 

 4-lobed, cup-shaped scale-leaf also decays, and only its stiff 

 veins remain, so that instead of the cup there are now^ only 

 comb-like scales. After this alteration has taken place, the 

 tissue of the stem below the pectinate scales breaks across, and 

 the whole shoot-apex, separated from the lower part of the 

 stem, which has long been in a leafless condition, is carried 

 away by the currents of the water," 



The views expressed by these eminent authorities will 

 require considerable modification when it is realized that the 

 new plant springs, not from any reduced leaf or scale-leaf, but 

 from the female flower itself. 



At the beginning of this year Mr. H. H. D. Griffith called 

 my attention to this plant, which grows beyond low-water mark 

 at Henley Beach, and is often cast up on the shore. He suc- 

 ceeded in finding several male flowers and also the female 

 flower in such various stages of growth as enabled us to trace 

 its gradual development up to the "comb." The flowers are 

 dioecious, and both male and female grow at the end of rather 

 short branches, sheltered by the broad sheaths of the two upper- 

 most leaves. The males have no other protection, and consist 

 of two 4-celled anthers on a common peduncle. Each anther 

 opens from below in 3 valves and emits the threadlike pollen- 

 cells, which float about in the water until they find the slender 

 stigmas of the female flower. This consists of twin carpels on 

 a common peduncle, one carpel often abortive. Like the males, 

 they are at first sheltered in the leaf-sheath, but they have also 

 in most cases a row of membranous bracteoles, often united in 

 the shape of a cup which completely encloses the flower. As 

 soon as fertilization has taken place the long stigmas break off, 

 and without any period of rest the embryo begins to grow and 

 the fruit to form. Four small truncate lobes, which have 

 appeared about the middle of the carpel, increase rapidly in 

 size and spread outwards, assuming the appearance of a 

 perianth. Fleshy on the outside, they soon develop a horny 

 inner framework, whose short, tubular part forms the inner- 

 most layer of the pericarp and protects the growing embryo. 

 Nourished by the albumen stored about its base, the embryo 

 b2 



