[ 252 ] 



1l3alf^an^*toour at tbe fiDicroecope 



Mitb /llbv, Unttcn Mest, jf,X»S., jf»1R./in),S„ etc 



Sphseria (PI. XVIII., Figs, i — 7). — The specimen before us is 

 a portion of leaf, having on it one of the SphcericE. The genus is 

 a member of the Ascomycetous fungi, and contains a vast number 

 of species. For complete identification, it would be needful to 

 dissect a portion, when the form and size of the asci (little trans- 

 parent sacs containing the spores), and of the spores themselves, 

 might enable the species to be named. In Greville's " Cryptoga- 

 mic Flora of Scotland " are many beautifully engraved and 

 coloured figures of Sphcei-ice^ by consulting which it is not unlikely 

 that much assistance towards identification might be obtained. 

 It is unfortunate that the specimen is mounted with an opaque 

 background, because we are unable to see both surfaces of the 

 leaf; that exposed to view appears to be the upper, but I am not 

 acquainted with any leaf the structure of which entirely agrees 

 with this. The leaf appears to be thick with a polished surface. 

 By a fortunate accident we discover that it is from a plant having 

 Sphaeraphides, and so another clue is obtained which may mate- 

 rially faciUtate identification. The diagrams on PL XVIII. illus- 

 trate the interesting structural relationship between the SphcErice 

 (Ascomycetous) and yEcidia (Coniomycetous) Fungi. 



Hairs of Onosma tauricum (PL XVIIL, Figs. 8 — 10). — The 

 plant yielding this belongs to the natural order Boraginacece. It 

 comes from the Caucasus, and is occasionally cultivated in this 

 country. The long, sabre-like hairs, with six smaller arranged 

 star-wise around them on an expanded base, form a pleasing 

 object. The specimen should have been mounted so that the 

 other surface of the leaf could have been seen as well. I judge 

 that the under-surface is presented to the eye, but do not dis- 

 tinctly make out the stomata, which are relatively very small in 

 plants of this order. A point of special structural interest 

 attaches to hairs like these, rough with outward projections. 

 *' What are these projections ? " " How are they produced ? '^ In 

 the " Histological Catalogue of the Royal College of Surgeons," 

 Vol. I, p. 3, we are informed that it is by a "deposit of new matter 

 on the external surface of the membrane." And that in the col- 

 lection at the College (Ppn., A. 13) is " a preparation of the por- 

 tion of a hair from the fornix of the corolla of Aiichusa italica, 

 exhibiting a deposit of tubercles of new matter on its external 

 surface. Each tubercle contains two or more cavities, and a 



