236 



Stow : Diatoms taken at Clee, Lincolnshire. 



situations, and also abundantly on moist decaying g-ritstone 

 rocks. There is also a slender laxly tufted form on damp sides 

 of brooks, very similar to (3) in habit. 



(3) . Webera annotina. Bulbils shorter and much thicker 

 than in (2), resembling in shape those of (1), but smaller, green, 

 several, np to about 6, to each leaf along- the greater part of the 

 stem. Plant slenderer, paler green in colour, in lax patches ; 

 leaves smaller, more distant, and more spreading- in comparison 

 with (1) and (2). It grows in moist situations on the sloping- 

 sides of old roads and ditches. 



(4) . Webera bulbifera. In habit and situation, and in the 

 position and number of the bulbils resembling- (3) ; the bulbils 

 themselves, however, being quite different. In shape they are 

 like a roundish egg attached by the narrower end, the upper half 

 being an empty hollow space, which is arched over by valves 

 (foliaceous points), with their edges in close contact. If the 

 bulbils be dried and then moistened again, the contained air 

 is not at once expelled, and the shape of the cavity is easily 

 seen. 



The bulbils are to be found during summer and autumn, and 

 perhaps at other seasons. Although they vary somewhat, their 

 distinctive characters seem well maintained. In all these forms 

 the leaves seem to be longly and narrowly decurrent, and 

 in (1) and usually in (2) they are larger and more erect, and 

 have more of the margin recurved than in (3) and (4). I do not 

 know how these forms are related to the varr. angustifolia and 

 tenuifolia of the ' Student's Handbook,' as I have no authentic 

 specimens for comparison. 



NOTE on LINCOLNSHIRE ALG/E. 



Diatoms taken at Clee, Lincolnshire. — Mr. A. Smith, of Grimsby, 



sent me the following- list of diatoms taken by him at Clee (Div. 4) 23rd 

 March 1902 : — 



Meridion circulare. Pleurosigma acuminatum. 



Synedra ulna. Pleurosigma atienuatuni. 



Synedra ulna var. vitrea. Mastogloia Smithii. 



Synedra acus. Rhabdonema arcuatum. 



Xitzschia linearis var. tenuis. Nitzschia sigmoidea. 



Xitzchia paradoxa. Rhoicosphenia curvula. 



Surirella ovalis var. angusta. Navicula didyma. 



Amphora angusta. Cymatopleura solea. 



Xavicula cryptocephala var. exilis. Diatoma elongatum. 



Fragilaria hyalina. Xavicula viridis. 

 Pleurosigma Spencerii. 



— S. C. Stow, Court Leys, Brandon, Grantham, 30th April 1902. 



