186 Scientific Proceedings, Royal Dublin Society. 



body in a more or less horizontal direction. After a horizontal growth of 50- 

 300 cm. the end turns downwards and buries itself in the ground. The buried 

 lower tip now develops as a root, while the part just above the level of the soil 

 greatly increases in diameter. Soon a longitudinal split in this enlarged region 

 allows the developing plumule to emerge. These relations are very well seen in 

 fig. 1, PI. VII, which is a photograph of a fruit of Lodoicea germinating in Kew. 

 We are indebted to Dr. A. W. Hill, f.r.s., for this interesting picture. 



The whole growth of the embryo until it forms connexion with the soil is 

 evidently made at the expense of the material stored in the seed and transmitted 

 through the cylindrical body to the growing parts. Even for a long time 

 after the root has entered the soil much nutriment is conveyed to the embryo 

 from the seed. Farmer (.5) records a case in which connexion was maintained 

 between the seed and the young plant for five years. 



Morphologists seem agreed that the organ connecting the young plant and 

 the seed is the cotyledon (14). The basal part of this leaf forms a complete 

 circular attachment at the first node of the embryo, and is excavated into a 

 conical cavity overarching the plumule. Above this cavity the walls converge 

 and form a solid cylindrical petiole, which is continued into the seed. Within 

 the seed its distal end expands into a bilobed, rounded mass — the haustorium. 

 The surface of the haustorium is corrugated and thrown into manj' folds and 

 ridges_; secondary folds imposed upon these make the surfaces of the larger 

 corrugations densely papillose. This papillose surface is in close contact with 

 the store material tilling the seed, and exposes a very large area to the latter, 

 both for the excretion of dissolving enzymes and for absorption. 



By the kindness of Dr. A. W. Hill, we were able to make a histological 

 examination of a germinating seed. The seed was one of four which germinated 

 during 1922 at the Royal Gardens, Kew ; and, having shown signs of retarded 

 growth, was most kindly placed at our disposal. 



The embryo was then protruding from the shell about 30 cm. It had a 

 twisted and seared appearance. When the seed was opened, the haustorium 

 was found to be about 10 cm. in diameter. It was of an irregularly rounded 

 form, deeply grooved and papillose. It was creamy white, and contrasted with 

 the bluish white of the endosperm. A narrow neck connected the haustorium 

 with the petiole, apparently deeply constricted by the shell of the fruit. The 

 distal part of the petiole with which this neck was connected was flattened by 

 the pressure of the two lobes of the frait. Once clear of these lobes, the petiole 

 became approximately circular in section. 



The outer surface of the petiole was marked with irregular longitudinal 

 grooves and ridges. It was brown in colour, with irregular white 

 blotches. Its transverse section was limited by 4-6 layers of parenchymatous 

 cells, the contents of which had disappeared, and the walls alone of which 

 persisted. These cells in transverse section are about 002 X 002 mm. They 

 are about 007 mm. in length. Within them there follow 4-6 layers of 

 sclerenchymatous cells, about 001-002 mm. in diameter and 006-008 mm. in 

 length. Their thickened walls almost completely obliterate their lumen. 

 From the sclerenchymatous layer inwards the mass of the petiole is composed 

 of thin-walled parenchyma built of cells, which in the outer regions are 

 comparatively small, viz., 001-0 03 X 006-008 mm., while in the inner regions 

 the dimensions are 005 X 010 mm. or more. Scattered among these cells were 

 many tannin-sacs, and throughout the tissue were inter-cellular spaces. There 

 was no starch in any of these cells. 



Embedded in this fundamental tissue were the vascular bundles to the 

 number of 800-1,200 in one cross-section. They exhibited the usual structure 

 of the vascular bundles of xerophj'tic monocotyledons. One of them is repre- 



