42 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



Mr. Hales exhibited the seedlings at the meeting of the Scientific 

 Committee on April 28, 1908, and I have been asked to contribute a short 

 note on the exhibit. 



The subject being one which is better treated by means of illus- 

 trations than by descriptions, the accompanying figures, all of which 

 are natural size, have been prepared and render a long account 

 unnecessary. 



Fig. 11, l represents an early stage in germination. The seed coat has 

 broken, and the primary root has developed to a slight extent ; the tip of 

 the hypocotyl, with the two minute cotyledons, is still contained within 

 the prothallus. This condition does not last for long, the hypocotyledonary 

 axis is soon removed from the seed and grows upright (fig. 11, 2). 

 Attention may be drawn to the fact that the seed-leaves are still quite 

 small, and do not function as organs of absorption, this role being per- 

 formed by a highly specialised organ, the foot or sucker, which is buried 

 in the tissue of the seed which contains the reserve food-materials 



(fig. 11, 2). 



The third illustration represents an older seedling having the cotyledons 

 more developed. Before drawing this specimen the seed itself was 

 entirely removed in order to show the rod-like character of the foot. It 

 will be observed that the radicle is still very small, although lateral roots 

 have made their appearance, a character which recalls the features obtain- 

 ing in the seedlings of a large number of Monocotyledons. The primary 

 root of Gnetum, however, does not remain stunted for long ; it elongates 

 and forms a prominent root of the same nature as that found in the 

 majority of Gymnosperms (fig. 11, 4). As development proceeds the 

 cotyledons increase considerably in size, and perform an assimilatory 

 function (fig. 11, 5). It will be observed that the seed-leaves of the 

 plant represented in the fifth illustration are unequal in size ; this is 

 a feature which is not at all uncommon in the seedlings of Gnetum 

 Gnemon. 



Fig. 11, 6, represents the upper part of an older seedling, and shows the 

 first pair of foliage leaves which are arranged on the axis at right angles 

 to the plane of insertion of the cotyledons. Further, it will be noticed 

 that the seed-leaves, partly indicated at the base of this drawing, have 

 grown considerably (cf. fig. 11, 5). 



Summarising the chief features of interest- 



1. The foot is a prominent structure containing vascular tissue and 

 developed to a greater extent in Gnetum than in either Welivitschia or 

 Ephedra. 



2. The primary root is at first very slow in its development, being 

 D( ithing more than a peg-like structure. Later, it grows rapidly and forms 

 a well-marked tap root. 



3. The cotyledons at first are very small indeed ; after some time they 

 expand considerably and resemble the foliage leaves. They are often 

 unequal in size. 



Much information concerning the structure of the seedlings of Gnetum 

 may be found in a paper by Professor F. 0. Bower, entitled " The 

 Germination and Embryogeny of Gnetum Gnemon," in the " Quarterly 

 Journal of Microscopical Science," vol. xxii. 1882. 



