October 2 i, 1909J 



NA JURE 



499 



PERCY SLADEN MEMORIAL EXPEDITION 

 IN SOUTH-WEST AFRICA, 190S-9.' 



II. 



T X the latitude of Loancla (Sif S.), behind a dry, sparsely 



populated coastal belt ;ibout 150 miles wide, lies a 



moimtaiiious zone, for the most part densely forest-covered 



I. — A glade in the Bauhinia forest showing a Ejobab just before the beginning of leaf'Tall 



to an elevation of 4000 feet. Within this zone is the 

 historic locality of Golungo Alto, where VVelwitsch lived 

 for two years, and in which a large part of his rich 

 collection was obtained. Here he discovered Giietum 

 africanuiH in 1855. 



A few miles to the south-east of Queta, a station on 

 the railway within the forest zone and not far from its 

 eastern edge, is situated the Government 

 experimental plantation (Granja San 

 Luiz), under the energetic direction of 

 Mr. J. Gossweiler, to whom I am in- 

 debted for valuable advice and assistance 

 during my residence there from April 

 1-12. The forests are here very dense 

 and the undergrowth thick and very 

 varied in character, .^fter an unsuc- 

 cessful search of some days' duration, 

 Gnetum was eventually found on April 7 

 in a very dense and dark forest on the 

 coffee and rubber estate of Montobello 

 (2600 feet), some thirty miles to the west 

 of Granja San Luiz and ten miles south 

 west from the raihvay station of Oueta. 

 It was very abundant within a strictly 

 limited area and its occurrence is clearly 

 "sporadic," as described by Welwitsch. 

 It may be noted that the native name 

 *' N-coco " given by Welwitsch is now- 

 applied indifferently to various plants of 

 climbing habit: of Gnetum itself the 

 natives seem to have no special know- 

 ledge. 



Leaving Loanda on April 16, I arrived 

 on .April 21 at Mossamedes, where the 

 third section of the journey commenced. 

 Quite exceptional rains had recently 

 fallen here, as in so many other districts to the south, and 

 the gently rising plains behind the town resembled a waving 

 cornfield rather than a desert. They supported a thick, 

 uniform growth of a tall Aristida (? A. prodigiosa, Welw.), 

 among which there flourished a considerable number of 

 small annuals. In sandy places, especially in shallow, dry 

 1 The fir-l article appeared in Nature of October 14. 

 NO. 2086, VOL. 81] 



water-channels, dense crops of the erect plumose awns of 

 .\ristida seeds, forced beneath the surface by their hygro- 

 scopic movements, were commonly seen. So unusual a 

 supply of food had tempted into the vicinity of the town 

 springbok, gemsbok and other antelopes, while ostriches 

 had reappeared after an absence of many years. Very 

 large Welwitschia plants were found in abundance about 

 eight miles to the south of Mossamedes in the direction 

 of Cape Negro, the locality in which it 

 was discovered by Welwitsch. The 

 plants had coned freely, but almost 

 without exception the cones, severely 

 attacked by a fungus (probably a Clado- 

 sporium), were in a state of decomposi- 

 tion — no doubt another consequence of 

 the excessive atmospheric humidity 

 earlier in the season. A large number 

 of young seedlings were found. The 

 Damaraland localities previously referred 

 to, in which no Welwitschia seedlings 

 have been found within recent years, are 

 about forty miles from the sea. But 

 even in these southern latitudes normal 

 seed-reproduction seems to occur on the 

 coast. A recent letter from Dr. Hin- 

 trager, Acting Governor of German 

 South-West Africa, contains the interest- 

 ing statement that '* wenige Kilometer 

 nordostlich von Cape Cross ' die Wel- 

 witschia noch haufig und in fast alien 

 .Alterstadien, also auch in jungen 

 Pflanzen vorkommt." It is not improb- 

 able that a condition of its seed-germina- 

 tion in nature is a degree of atmospheric 

 humidity which is constantly realised 

 near the sea though now usually absent 

 from desert places inland. 



On April 27 I left Mossamedes with 

 the intention of crossing the Huilla 

 plateau and reaching the Cunene River. I was accom- 

 panied by Mr. H. G. Mackie, H.B.M. Consul in Angola, 

 to whose kind support the success of this part of the 

 journey was very largely due. The light railway, at 

 present working to the 107th kilometre, leaves Mossamedes 

 in a northerly direction and crosses the broad beds of the 

 periodical rivers Bero and Giroual, in which, near the sea. 



pposite Fort Ro^adas, looking t 



a few tropical and subtropical crops are cultivated. So 

 far inland as the present railhead, the rainfall is small and 

 inconstant and, in normal seasons, the country is prac- 

 tically waterless. At about 80 km., however, the typical 

 desert vegetation mingles with shrubs and a few dwarf 

 tiees, which are found in greater luxuriance on the lower 

 1 1 at. 21-9 S. 



