April 1, 1897.] 



KNOWLEDGE. 



89 



England is surely no reason why its antiquarian remains 

 should be transported to London." We heartily sympathise 

 with this view of decentralization in archaeology, providing 

 there is some system of recording at the central institution 

 the treasures thus locally cared for. 



For the purpose of defraying the cost of the survey, and 

 also forming a fund sufficient to protect the monuments. 

 Dr. Murray proposes to ear-mark the funds arising from the 

 estates of intestates reverting to the Crown. We do not 

 care for ear-marked funds, and should prefer to leave the 

 ways and means to the Chancellor of the Exchequer. One 

 question remains. Where is the enterprising Member of 

 Parhament who will make this question of an archaeological 

 survey his own '? 



The address is accompanied by three most valuable 

 appendices ; («) Questions addressed to its correspondents 

 by the Comite Historique des Arts et Monumens ; {b) the 

 law as to injury to ancient monuments in England, France, 

 and Germany ; (c) an admirable summary of the law as to 

 treasure trove. 



THE MAPLE MOULD. 



By Rev. Alex. S. Wilson, M.A., B.Sc. 



ON the leaves of the plane tree or sycamore our 

 readers must frequently have observed numerous 

 black spots, each about half an inch in diameter. 

 In some parts of the country hardly a leaf of this 

 tree can be seen in autumn which is not dis- 

 figured by their presence. While still fresh and green on 

 the tree, the foliage appears as though it had been 

 bespattered with ink, and even on the brown withered 

 leaves after they have fallen the dark spots are highly 

 conspicuous. These blotches are caused by a parasitic 

 fungus, Ehytisvta acerinum, the maple mould, one of the 

 Ascomycetcs, an order of somewhat higher organization 

 than the I'lrdincg described in Knowledge for November, 

 189G. Other species of FJiytisma grow on wiUows, on 

 Andromeda, one of the heaths ; and on the nettle. 

 Saccardo, in his " Sylloge Fungorum," describes no less 

 than sixty-three species, from various parts of the world, 

 parasitic on rhododendrons, magnolias, cacti, pines, and 



Fig. I. — The Maple llould (7f /ii//!sma acerinum). 



other plants. The generic name, from a Greek word 

 meaning to dye or stain, is singularly appropriate, for 

 leaves attacked by the fungus are stained in a very striking 

 manner indeed {see Fig. I.). 



By scraping a discoloured portion of a leaf and mounting 

 on a microscopic slide we readily discover among the 

 debris little fau-like tufts of elongated tubular cells, which 

 are seen to be of two kinds ; some are simply blunt hairs 

 or paraphyses, others are linear or club-shaped sacs — the 

 asci — each of which contains eight small rounded bodies, 

 the ascospores {see Fig. II, 1). 



1. lihijtisnia. 



Sphreria. 



A short search among grass during the winter months 

 is sure to result in the discovery of numerous specimens 

 with their leaves looking as if minute drops of tar had 

 been sprinkled upon them. These black shining spots are 

 not uncommon on the cock's-foot grass {Bactylis ylomerata), 

 and are caused by species of Sphmria, a genus closely 

 allied to Uhytisma. Its asci are larger, and may be easily 

 extracted by moistening an affected portion of the grass- 

 blade and teasing it out on a glass slide. Each ascus, 

 as in Ehytisma, contains eight ascospores (Fig. II. 2.) 



The Ascomycctes arc a very extensive order, including 

 several of the larfjer fungi, such as the truffle, the morel, and 

 the numerous Pi'^i:ce, some of which possess an elegant cup- 

 like shape, others being brilliantly adorned in orange and 

 scarlet. Many grow on rotting wood ; the little scarlet 

 cushions of Nectria dnnabarina, so common on old sticks in 

 every garden , must be familiar to many of our readers. ther 

 Ascomycetes live among moss, on dead leaves, or on the 

 ground, deriving their nourishment from the decayingorganic 

 matter in the soil. Some occur as moulds on fruit, bread, 

 jelly, and the like ; a few are developed in the bodies of 

 living caterpillars ; while a considerable number are 

 parasitic on growing plants, and give rise to mildew and 

 blight. The vine disease, which for some years wrought 

 such havoc in the vineyards of France and Spain, is caused 

 by Erysiphe Tuckeri : the hop blight by Podospharia 

 ctistaynei : the rose mildew by P. pannosa : another, Claviceps 

 purpurea produces ergot on rye and other grains, rendering 

 them unfit for food, and even poisonous. The lichens, 

 those grey and orange incrustations so common on rocks 

 and trees, should also be mentioned, since a hchen is 

 simply an ascomycetous fungns which lives parasitically 

 upon a number of unicellular algas. Yeast is placed by 

 some in this order, and De Bary is of opinion that the 

 I'redines sxQ a group of degraded Ascomycetcs. 



The spore sac or aseus is a structure characteristic of 

 the whole series, and gives its name to the order. The 

 subdivisions are distinguished by the nature of the sporo- 

 earp or body which bears the asci. The Discomycetes 

 produce their asci on the surface of a flat or cup-shaped disc : 

 the Pyrenomycetes develop theirs in the interior of flask- 

 shaped receptacles or perithecia ; while Erysiphe and Tuber 

 are cleistocarpous, having their asci in closed sporocarps. 



The wall of the sporocarp in many species consists of 

 dense hardened cells, occasionally highly coloured, but 

 more frequently brown or black. A vertical section 

 through a grass blade with Spluerin on it shows a row of 

 rounded perithecia sunk in the substance of the host, each 

 invested with its black rind (Fig. III. a). When mature 

 the asci protrude through an opening at the top of the 

 perithecium and eject their ascospores. The perithecia of 



