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6 



YORKSHTRE NATURALISTS UNION 



It is impossible to find a permanently moist situation in 

 which algx are absent. They are found on damp earth, rocks, 

 walls, palings, shaded tree-trunks, in spouts, rain-tubs, etc. ; 

 they arc met with again in all kinds of running water, from the 

 tumbling cataract and rat)id torrent to the slow, majestic river; 

 but it is in t)erfecdy ciuiet waters that they are most prolific, 

 whether it be in the tiny moor-]}Ool or the expansive lake. 

 Some even find shelter in symbiotic relationship with other 

 plants; for instance, a species of AnakcHa lives with the aciuatic 

 l.yeopod Azol/a, and another lives with the Hepatic Blasia, to 

 say nothing of those associated with fungi to form the com- 

 pound dual organism known as a lichen, or those symbiotically 

 connected with such animals as Hydra virldis and certain species 



of AjiKiba. 



Many of the larger freshwater alga^ are noticeable as green,- 



slimy masses floating on the surface of or attached to the sides 

 of ponds, ditches, rivers, etc. Small tufts of these are best col- 

 lected in tubes or small bottles. Constantly dripping rocks yield 

 quite characteristic species, and even shady, moist rocks have 

 an alga-fiora of their own. On veitical, moist rocks (especially 

 limestone) it is not uncommon to fmd coriaceous patches, or 

 ■gekitinous masses, of a red, brown, green, bluish-green or 

 blackish colour, and an examit-iation of such masses is always 



interesting, 



There are a vast number of beautiful alg;e which are very 

 minute, and the places in which they abound are not usually 



obvious to the casual observer. They generally occur about tl 

 stems and leaves of submerged plants, such as Ulriculana 

 minor, Myriophyllum, NympJum, Nuphar, Potamogelon, Scirpus 

 Jluitans, Isoch's, etc. Many of the Muscinea^, such as Sphagnum 

 contortum, S. phimosum, Amhiystegium scorploides, A.fakatnm, 

 A. exannuldtun}, A. ghviann, Fontuialis a/ilipyrelica, Jungcr- 

 mauuia w/Iafa, Nardia emarginaia, etc., are often richly clothed 

 with small species. ^I'he best way to cohect from plants of this 

 kind is to remove them (or portions of them) from the water with 



Trans. Y.N.U., 1896 (pub. Aug. 1900). Bot. Series, Vol. 5. 





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