Apbil 1, 1897.J 



KNOWLEDGE. 



91 



fication some resemblance to a mop or brush (Fig. V. 2). 

 Sometimes the gonidia are produced in receptacles 

 resembling perithecia ; these pycnidia in some cases can 

 hardly be distinguished from spermogonia, such as we find 

 in lichens and associated with the cluster-cups or the 

 rredines. Pycnospores germinate more freely, however, 

 than spermatia. Cucurbitaiia growing on laburnum bark 

 has four different kinds of pycnidia, but these organs some- 

 times appear on a mycelium to which they do not pro- 

 perly belong. On Erijsiphe pycnidia occur belonging to 

 Cicinnoholus, the slender mycelial threads of which traverse 

 the thicker ones of Knjsiphe. Nor are such cases un- 

 common where one fungus preys upon another which is 

 itself parasitic. Pedta rhytisma, as its name indicates, 

 selects the spots of the maple mould as its peculiar 

 habitat. The well-known lines of Swift apply to the 

 vegetable as well as to the animal kingdom : — 



" So, naturalists observe, a flea 

 Has smaller fleas that on him prey; 

 And these have smaller still to bite 'em. 

 And so proceed ad injinitum.''^ 



Another Ascomycete which attacks the leaves of maples 

 is Uncinula bicornis : its sporocarps are minute dark- 

 coloured spherical bodies, but Melasiiiin aceiinum is not a 

 distinct fungus — its supposed pycnidia are really the 

 spermogonia of Rhytisma. In this instance what is truly 

 a part of the plant itself was long mistaken for a parasite. 



The mechanism for the discharge and scattering of the 

 spores in many of these microfungi is very curious, and 



Fl&. V. — Gronidia. 1. GmssMoiild (Eri/sipJie r/rnminis). 

 2. Blue Mould [Eiiro/iiim aspergillus glaiicus). 



quite equal in interest to the contrivances by which the 

 dispersion of seeds is effected in flowering plants. In 

 Spharia the cell-membrane of the spore sac is highly 

 extensile ; each ascus as it ripens suddenly stretches itself 

 up half way through the opening of the perithecium, and 

 from its apex discharges the ascospores swiftly one by one 

 like so many arrows. Similar lively proceedings may be 

 observed in Ascoholus. The ripe gonidia of Pilobolus, 

 Copmiiis, and others are thrown off by the explosion of a 

 subjacent cell. The stalks of the spores in other instances 

 are twisted, and so hygroscopic that the slightest change 

 in the humidity of the air produces such rapid torsion that 

 the gonidia at their extremities are twirled away. Bliythuia, 

 in common with many PiKhce, exhibits the phenomenon 

 of puffing, which consists in the emission of a little cloud 

 of spores in consequence of many asci discharging their 

 contents simultaneously. The spores of some Spharke 

 have a gelatinous appendage ; those of Rhytisma an- 

 dromeda are coated with viscid matter, provisions enabling 

 them to adhere readily to their hosts. Rhytisma produces 

 its asci in spring ; there are many points in its life history 

 which still require investigation. 



Science Notes. 



By courtesy of the Eoyal Geographical Society, we are 

 enabled in the accompanying illustration to give an exact 

 reproduction of the gold medal which the Society struck 

 for Dr. Nansen. The medal was presented to Dr. Nansen 



by H.R.H. the Prince of Wales, at the great meeting in 

 the Albert Hall, on the 8th of February, 1897. On the 

 same occasion a silver replica of the medal was handed 

 to Lieut. Scott Hansen, and similar replicas were after- 

 wards sent to Captain Sverdrup, Lieut. .Johansen, and 



Dr. Blessing. The eight other members of the expedition 

 received bron7e replicas of the medal. Upon a riband in 

 the upper part of tlie medal is the word " Fram," the 

 Norwegian for "Forward," and used here as a motto. 

 The Fmancial Committee of the Norwegian Storthing has 



Reverse. 



unanimously adopted a proposal in favour of granting four 

 thousand kronor to each of Dr. Nansen's twelve com- 

 panions, and three thousand kronor yearly during a period 

 of five years to Captain Sverdrup, who will be at the head 

 of the next expedition in the Fram planned by Dr. Nansen 

 for 1898. No Parliamentary grant is demanded for the 

 expenses of this new expedition. Lecturers will be pleased 

 to hear that the lantern slides used by Dr. Nansen at his 

 lectures can now be obtained of Messrs. Newton & Co., 

 who made them for Dr. Nansen. The distinguished 

 explorer has been appointed Professor of Zoology at 

 Christiania University, and has also received honorary 

 degrees in this country. 



