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
