PRESIDENTIAL ADDRESS. 327 



the powerful aid of Kew, cacao growing was started in a small way among 

 the negro peasantry, with eventually extraordinary results. After selecting 

 the locality for the experiments, seeds and plants were obtained through Kew, 

 and a trained man was placed in charge.'' The first exports in 1891 amounted 

 to a value of £4 only. So rapid was the development of the industry that ten 

 years later the exports reached a value of £43,000. By this time both the 

 people and the G-overnnient had begun to realise the possibilities of the situation, 

 and systematic steps were taken to organise under scientific control a staff of 

 travelling agricultural instructors to advise and assist the cultivators in dealing 

 with fungoid and insect pests and improving the quality of the produce. In 1911 

 the exports had increased nearly fourfold, and reached a total value of 

 £1,613,000, while in 1916 what may possibly be regarded as the maximum 

 exports were of the value of £3,847,720. 



It should be borne in mind that this Gold Coast cacao industry, now one 

 of the largest in the world, has been called into being and developed entirely by 

 the agency of unskilled negro labour, and on small plots from one to five or 

 ten acres in extent. The controlling factors were, first, the selection of suitable 

 land for cacao growing ; next, the selection and supply of seeds and plants of 

 varieties adapted to local conditions ; and, lastly, the tactful advice and assist- 

 ance of trained Europeans backed by the resources of science. 



Coming nearer home, Henry, well known from his association with Elwes in 

 the production of ' The Trees of Great Britain and Ireland,' by historical 

 research and experiment has established the fact that many fast-growing trees 

 in cultivation as the Lucombe Oak, Common Lime, Cricket-Bat Willow, Black 

 Italian Poplar. Huntingdon Elm, etc., are hybrids. It was of high scientific 

 ■ importance to discover the origin of these valuable trees. Further, by artificial 

 pollination Henry has succeeded in raising new hybrids which display the extra- 

 ordinary vigour characteristic of the first veneration cross. Perhaps the most 

 notable, so far, is a new hybrid Poplar [Pcrpuhts generosa), which makes the 

 strongest shoots of all Poplars. 



The astonishing vigour of hybrid trees is well illustrated in the case of the 

 Cricket-Bat Willow, a natural cross between Salix fragilis and S. alba. ' Thie 

 of tens attains in fourteen or fifteen years, from the planting of sets, fifty to 

 sixty feet in height, with three and a-half to four feet in girth — a size suitable 

 for cleaving into bats.' It is claimed in the case of many hybrid trees 

 'it is possible to produce much greater bulk of timber in a given time.' The 

 common belief that quickly grown timbers are of inferior quality is said no( 

 to hold good in respect of any quality in Ash, Oak, and Walnut. In fact, 

 according to Dawson, 'with Oak, Ash. and Walnut the quicker their growth the 

 better tbeir qiiality in every way. THey are more durable, more elastic, and 

 less difficult to work.* It is further claimed that by hybridising it may be 

 possible to produce disease-resisting varieties and varieties carrying with them 

 other desirable characteristics. 



Difficulties are met with in hybridising trees in this country owing to the 

 variable climate and the absence of pollen and desirable sorts. To obviate these 

 and provide adequately for the work it should be undertaken on organised lines, 

 as in wheat breedinsc. 



Henry has recently made an elaborate investigation into the history of the 

 London Plane [Platanux acerifolia).^ He has established the fact that this 

 tree, never seen anywhere in the wild state, is intermediate in character 

 between an American and a European species. He claims it has all the pecu- 

 liarities of a first cross. As nsnal in hybrids of the first sreneration, its seeds 

 when sown produce a mixed and varied crop of seedlings, in which are 

 variously combined the characters of the two parents. 



Henry's researches show that the London Plane probably originated in the 

 Oxford Botanic Garden about the year 1670, when both the occidental and oriental 

 Planes were established there. The finest and probablv the oldest London 

 Plane in Europe is growing in the Palace Garden at Ely. It was planted 

 by Bishop Gunning between 1674 and 1684. The vigour of the London Plane 



< Kew Bull 1891. 169: 189.5. 11. 



5 Ffrience and th' Natinv. 1.S8. 



^ Proc. Roy. Irish Acady. XXXV. B.2.10. 



c c 2 



