The Sudd. 303 The third or last class of sudd is composed entirely of plants which swim upon the surface of the water. These form the cementing medium which binds the first two classes together.

The following are the principal components of this class : — Pistia, a small cabbage-like plant with bright green leaves. AzoUa, resembling moss in texture. Vtricdaria, Aldrovandia and Ceratophyllum, all resembling feathery floating streamers. The first variety has a series of small bulbs, like floats, attached to each streamer. The last is common in the canals and drains of Lower Egypt.

Otellia, a plant with big leaves and a white flower like a lily.* It is found everywhere in this class of sudd, and is met with at Damietta, where it is called by the Arabs " Lughmet el Kadi," or the " Kadi's pudding."

In and among the above the blue-flowered creeper (Commellaria) is found. Regarding the detail of the formation, the first point of interest is that all the most important sudd plants propagate j)etail themselves by means of tubular rhizomes which run along the surface of the water giving out shoots from point to /lyj Broun ) point. These shoots, after developing, give out other runners which cross the others and weave themselves into them, a further consolidation being given by twiners which bind them all together.

The most important sudd plants are, without doubt, Papyrus, " Um suf " (Panicum pyramidale), and " Bus " (■,f y„jj {Phragmites communis). plants.

" Um suf " is probably the greatest source of blocks in the river courses, as it seems to thrive in deeper water than either the " Papyrus " or " Bus." But all these give out long rhizomes. Those of the "Bus," which is a very tall reed, extend sometimes quite 20 yards from the parent plants. These rhizomes either break away when the new shoots have developed and go to form new colonies elsewhere, or they are driven by the side of the others and gradually encroach on the river.

Among the climbers which bind the new growth (as well as the old) together, the principal are three kinds of Ipomwa, one vine and a leguminous twiner Vigna Nilotica. One of the Ipomwas (I. Reptans) deserves special mention, as it is not only a twiner, but possesses also tubular rhizomes, which enable it to float along the rhizomes of Papyrus, " Bus," or " Um suf," and to knit them together as soon as they give out shoots. Among other plants which have also hollow stems are Jussicea diffusa, which is also supplied with bunches of spine-shaped floats, and Pdy-(jonum tomentosum.

When all these floating masses are being tied together by the twiners the river brings down other plants as a packing to fill the interstices. The most common is Pistia Stratiotes, but there is also a constant supply of Ceratophyllum., Utricularia, Vallisneria and other plants of the same family ; also Trapa bispinosa (the water-nut), Potomogetuw , Azolla, etc. Little nooks are thus enclosed by rimners from the Bus reed, the interior spaces of which are crammed with smaller plants.

It appears wonderful that with all this enormous mass of vegetation growing in these vast swamps in which no I traces of human habitations can be seen, the natural decay of the plants does not gradually raise the level of the soil and force the water to keep to well-defined channels which, with the greater volume of water which they would contain Iwould soon force for themselves a less winding course than they now follow.

It appears that one of the chief causes of continuation of the old order of things is fire. Sparsely inhabited gti„„ ,,( las the swamps are, they are swept through from end to end by fierce fires which carry everything before them and fires.

sill nearly all the trees which attempt to gain a footing. Here and there a few Kakamut, Dom, Deleib, Dabka or Talh Ihave managed to spring up, but they are so scattered that they do not count. The papyrus and reeds, instead of lying a natural death and forming soil by decay, are burnt down, and what of the ashes is not blown away by the nnd is carried away by the next flood. Were it not for these fires it is probable that trees of the species mentioned ibove would spring out more abundantly, and it would not be a difficult matter to define the banks of the channel by plantations of these or other river-side trees, such as are to be found in Ceylon, for example, lining the river, e.g., erminalis glabra, Vitex Leucoxylon, Valeria acuminata.

In 1863, 1864, and 1868, heavy sudds blocked the Bahr El Jebel, and in the first mentioned year they extend Recent the north of Lake No. {"{st-fy " In 1870, Sir Samuel Baker found the Bahr El Jebel closed with sudd at its mouth in Lake No. He attempted ' '"'"' ascend the Bahr El Zeraf but failed to reach the Upper Nile, and was obhged to return. cutting.

In 1871 he ascended the Bahr El Zeraf, and eventually forced his way into the main river near Shambe, literally (Vaiious.) lifting his boats and steamer over the intervening swamps and shallows.

In 1872 both the Bahr El Jebel and Bahr El Zeraf were closed, and in 1874 Ismail Pasha Ayub cleared away fche sudd in the former river.

In 1878 Emin Pasha found it impossible to ascend the Bahr El Jebel from the south. In 1879 and 1880 Marno (an Austrian) cleared the Bahr El Jebel of obstruction, completing his work in April, 1880.

* Query Boottia Scabra or Nymphctea Lotus'! — .A.B.