BOTANY 



in the same county. In 1892 Mr. Druce found it in abundance near 

 Godstowe, Oxfordshire, but it does not seem to have occurred in that 

 station since. In 1896 Mr. Bullock- Webster collected it in some clay- 

 pits near Ely, and the following year on the Norfolk side of the river 

 Little Ouse near St. John's, Little Ouse. It has been recorded from no 

 other county in the British Isles. 



N.Jiexilis, Agardh, seems pretty well established in Fowl Mere, near 

 Thetford, and has also been found on the Norfolk side of the Little Ouse. 

 A curious Nitella which occurs in the Counterwash Drain at Welney, 

 west Norfolk, as well as higher up this drain in Cambridgeshire, 

 Messrs. Groves, after much consideration and investigation, assign to 

 N. jiexilis var. nidifica, Wallm., though it differs considerably from the 

 type (yiJe Fasc. ii. 59). 



N. opaca, Agardh, is a common plant distributed through no less 

 than seventy-three vice-counties of the British Isles, but it does not seem 

 to have been collected from many localities in Norfolk. 



There is still much to be done before the county distribution of 

 these interesting plants can be at all accurately estimated. The Order 

 is one which is much neglected by botanists. Possibly the difficulty 

 of collecting and preserving Charas in a measure accounts for this. They 

 never appear above the water, nor will they bear any lengthened exposure 

 to the air. It is necessary to transfer them from the water to an air- 

 tight vasculum with all speed. Many of the species, too, are exceedingly 

 brittle and delicate, and require very tender handling, indeed in the case 

 of the Tolypellas it is almost necessary to transfer the plants straight from 

 the water to the pressing-case if really good specimens are to be secured. 

 In deep waters it is necessary to use a drag, but preference should be 

 given to a long-handled hoe where possible. A hoe makes it practicable 

 to secure the plant by the root, and the root is generally the toughest 

 part of a Charad for handling purposes. A drag is apt to break and tear 

 the specimen. For plants within reach the hand is by far the best collector. 

 Most of the species require to be floated out under water, and to be 

 transferred to their paper in this condition, they are then placed between 

 ample sheets of drying paper, and under as strong a pressure as can be 

 obtained. After three or four changes of drying paper, and three or four 

 days' pressure, they are ready for the herbarium. 



Nitella capitata is the earliest of the Charads to show itself It may 

 be found in good condition towards the end of April. Tolypella intricata 

 and T. glomerata are a week or two later, whilst T. prolifera may be ex- 

 pected in its prime in the middle of June. Nitella Jiexilis and N. opaca 

 are at their best about the same time. N. translucens and N. tenuissima 

 are somewhat later, whilst N. mucronata is a summer plant. 



The Charas are less variable in their season. They are almost all in 

 a fruiting condition towards the end of June, and may be collected thence 

 onwards during July and August. 



The variations and forms of the Characeae are innumerable, affected 

 as they are by the water in which they grow, its quality and character, 



61 



