Article

A collection is thc starting-point for various types ofstudies buI il is also, and mainly, a remarkable didactic instr':lment. Thc knowledge or level of information (representativeness) contained in every sample is thc lIrst essenti al stcp in thc process or the spreading or information or a collection. Thc scope in this work is lo present an informatic package thal enables lO evaluate thc representativeness ofthe specimens and therefore ofthe whole col1eetion. A first practical approach has been conducted on a collection (forty eight samples) of geniculate Corallinaceae, known as "Nova Collectio Corallinales - TSB". The programme herewith pre· sented reports ali the expectcd characters, both determining (D) and descriptive (d), for the different species of calcareous algae (Lithophylloideae and Corallinoideae) present in the collection. The characters are arranged in sub·scctions on the thallus, branching, branches, intergenicula and conceptacles. To calculate the represenlativeness ofthe different samples, it is necessary to compare the number of expected (e) and observed (o) characters verifying, in the observed specimeo, the presence (with a tick) or expected characters far that particular species. Assuming that in th e "ideai specimen" the ratio Do/Dc and do/de equals I, ratio calculated both al the sub-section level and at the leve l of spec ics, is expressed by dispersion graphs that enable to detennioe immediately which sample is the most representative (x= 1; y=1), therefore more suitable for a didacticmuseum usage. The degree of represenlativeness of samples has been defined: al sub-section level, at level of species, at levc! of sub-family, at colleclion level. The programme allows, in its complete version, to introduce new research crileria, varying both the "targe! species" and thc level of accuracy aimed at during the scrcening of samples. Such an approach may also be applied lo olher scienlific areas; it leads lo a deep underslanding of the present co llection and lo fully exploit its potcntialities, both as an historical archive and as a source of data for subseq uent researches.