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THE TYSON COLLECTION OF MARINE ALGAE 
an Alga which is probably Pachymenia carnosa, J. Ag. In later times we have 
collections made by Harvey containing a large proportion of the total number 
of species recorded from the Cape; by Pappe on whose specimens Kiitzing 
founded many of his Cape species. A large collection of Algae was made in 
1889- 1890 by Mr L. Boodle and presented to the British Museum;... An un- 
named collection of Corallineae from the Cape still remains in the British 
Museum Herbarium collected by Bowerbank, Mr Boodle and others; there 
are also unnamed specimens of Chaetomorpha and Cladophora.” From these 
various sources Miss Barton compiled the list already mentioned. Other 
articles have appeared from time to time since the publication of the original 
list, adding further details of genera, or further records of Algae as additions 
to the original list. These are noted in the present list as far as possible. 
The Tyson collection includes a considerable variety of forms in which the 
preponderance of red seaweeds is at once noticeable. The same impression is 
made on even a cursory examination of the flora of the coast, at least round 
about the Cape Peninsula, which is the only region which we have ourselves 
observed. 
It is well known that the temperature of the waters on the east and west 
sides of the coast of S. Africa is very different. According to Miss Barton, 
“ On the East there is a strong warm current flowing southward from the 
Indian Ocean, bringing with it the tropical and subtropical forms (i.e. of 
Algae) to Natal and even to Cape Agulhas; while another branch of the same 
current flows direct from Mauritius, where the Algae are... very similar to those 
at the Cape, though the two places are in such different latitudes. On the west 
coast. ..there is a cold current which comes up from the south,... and this has 
naturally a marked effect on the Algae all up this coast. Indeed,... the genus 
Laminaria is recorded from Walfisch Bay, within the tropics, the only place 
in the world, so far as I know, where this is known to occur.” A similar 
difference is found between the waters on the two sides of the Cape Peninsula 
with which we are here more especially concerned, and is reflected to some 
extent in the distributions recorded in the following lists. Other factors, 
however, must also play their part in determining the distributions of the 
different forms, and one of these is probably the formation of the foreshore, 
which has rocks mainly of sandstone on the eastern side (especially in False 
Bay) and often of granite on the colder western side. The sandstone offers a 
rougher surface and is more easily eroded by the waves making many deep 
pools and clefts in which the smaller forms can find shelter. The granite, how- 
ever, affords but little assistance to the hapterons of marine plants, and in 
many places are bare of covering, in others only partly covered with Porphyra 
which may be found even in exposed places, impossible for any other Algae. 
The slate which adjoins the granite at Sea Point appears to be also a better 
substratum for Algae than is the granite. The Algae of the west coast are, 
