Cciv PROCEEDINGS OF THE ROYAL HORTICULTURAL SOCIETY. 



this green fluid possesses another character of considerable optical interest : 

 it is fluorescent. "When viewed by reflected light it is green, as is the 

 case when daylight is transmitted, not only ordinary daylight, but even 

 direct sunlight. When, however, an artificial light is viewed through it, 

 the fluid appears red ; the electric light, gas light, or even the flame of a 

 wax vesta match has the same effect. A solution of chlorophyll in 

 alcohol is also fluorescent, but in the reverse way, being green by trans- 

 mitted, and reddish by reflected light. (1) Indigo-red dissolved in alcohol. 

 This specimen is prepared from woad after the manner described by 

 Prof. M. W. Beyerick, of Delft : 1 To an infusion of fresh woad leaves, 

 isatin and hydrochloric acid are added, and the mixture boiled.' It 

 assumes a dark, almost black colour, which is due to the deposition of 

 innumerable acicular crystals of indigo-red, which are readily observable 

 under the microscope. These crystals are insoluble in water, so that if 

 the fluid be filtered they remain on the filter as a black powder ; this may 

 be dissolved by alcohol. (2) A red colouring matter soluble in water and 

 in alcohol. Obtained by treating dry woad seed with hot water and hydro- 

 chloric acid. This specimen is an alcoholic solution. This colouring 

 matter is turned green by an alkali, thereby differing from indigo-red. 

 (3) An alcoholic solution of red colouring matter contained in the flower- 

 heads of Hypericum perforatum. This has been known for a very long time. 

 Linna?us speaks of the Scandinavians colouring the spirituous liquors by it. 

 It is turned bright green by an alkali. (4) The male catkins of the black 

 Poplar crushed with water and hydrochloric acid. (5) Petals of Geranium 

 sylvaticum crushed with alum and water. (6) Petals of Centaur ea 

 Cyan us crushed with alum and water. This is said by the older botanists 

 to yield a ' blue ink ' ; but the mixture thus obtained can hardly be called 

 blue, but rather a dirty chocolate. It has, however, a red fluorescence 

 by transmitted light." These two last (5 and 6) are probably the so-called 

 erythrophyll. 



Cladium Mariscus. — Specimens were received from Dr. Plowright, 

 who writes : — " These distorted leaves were found upon plants growing on 

 Ashwicken Fen during the past season. Many plants were similarly 

 affected." They had evidently received some check during growth. 



Helenium autumnale virescent, dc. — Mr. Worsdell showed specimens 

 of this not uncommon malformation, together with an interesting account 

 of the. matter. (See page 943.) 



Crimson Oak Leaves. — Rev. W. Wilks showed leaves of the common 

 Oak which came from one single tree in a large wood, of a bright crimson 

 colour on both sides, especially on the lower side. It was remarkable 

 that no other trees bore such leaves in the neighbourhood. 



Scientific Committee, December 9, 1902. 

 Dr. M. T. Masters, F.R.S., in the chair, and ten members present. 



Carnation Leaves Booting. — Mr. Douglas observed, with regard to a 

 remark of Mr. Massee's — that roots are sometimes produced on the leaves 

 when the main roots were affected — that in the case of those he had 



