26 ON NAIAS GKAMINEA DEL.,.VAK. DELILBI MAGNUS. 



but there is one mill on the banks of the canal (Houldsworth's) 

 which consumes Egyptian cotton largely, and from it, if not from 

 others, the fruits of the Naias may have been transported to the canal. 

 Last autumn, Mr. J. Cosmo Melvill and myself carefully examined 

 the large condensing tank in the yard of this mill, but we could 

 not find a trace of the plant ; the water was of a high temperature 

 and little vegetation was found in it, but its depth was beyond our 

 means of properly. exploring it. 



Alire Eaffenau Delile * gives an account of the culture of rice 

 in Egypt, and shows that the water used for the young plants is 

 drawn fron the Nile by fixed machines during the principal part of 

 the year; but in times of inundation, during the rising of the river, 

 the water is naturally distributed, its particular course being 

 regulated by the embankments which protect the fields. He states 

 that the plant grows in the canals of the rice-fields at Kosetta and 

 in the Delta, but he considered it only a variety of Naias fragilis, 

 which grows in the same waters. 



The irrigation of modern Egyptian cotton plantations will be 

 effected by much the same means, the Nile, with its artificial 

 ramifications, being the chief water supply of the country. Fruits 

 of the Naias may reach Egypt from Abyssinia, or from the great 

 lakes of Equatorial Africa ; the Nile water supplied to the growing 

 cotton-plant will be accompanied by these fruits, some of which 

 would be left dry upon the surface after the water had percolated 

 through the upper soil, but they would not germinate there. 

 Either by the agency of the wind, or through accidental contact 

 with the soil, they become mixed with the cotton exported to 

 England. When the bales of cotton reach the Lancashire mills, 

 the fruits of the Naias would be removed in the blowing-room, or 

 by the carding-engines. The refuse is turned out of the mill into 

 the yard, whence the wind and other agencies transport the fruits 

 into the tepid water of the canal ; here they meet with a suitable 

 nidus for germination and growth, and the result is the appearance 

 of an alien in our flora. 



If these surmises have any substratum of truth, the Naias may 

 occur in any mill-pond connected with works where Egyptian 

 cotton is used, and where the water is raised to a permanently high 

 temperature by the condensation of steam from the boiler. As 

 Egyptian cotton is largely used in Bolton, the mill-ponds and 

 canals of that neighbourhood may be expected to contain Naias 

 graminea and other Egyptain aquatic plants, as Naias muricata 

 Del., Chara Braunii Gmel., &c. 



The Egyptian origin of the plant is to some extent confirmed 

 by the form of Chara Braunii which grows at Eeddish being very 

 near the form of that species which occurs in Northern Africa. 

 Whether there is anything showing an affinity to the Egyptian 

 plant in the peculiar form of Zannichellia which grows in the same 

 canal, I have not the means of determining ; but both it and the 



* ' Memoire sur les plantes qui oroissent spontanement en Egypte,' vol. ii. 

 pp. 16, 17. 



