Holotype fragment (botany)

Thu Jan 12 17:33:51 CST 2006

    Paul van Rijckevorsel <dipteryx at FREELER.NL> wrote:   * A "fragment of a holotype" only deserves status as any kind of type if it
is big enough to be a specimen (as defined in Art 8.2). A herbarium sheet
loses bits and pieces all the time (from molecules evaporating and up). If a
fragment is not big enough to be a specimen then it cannot be a isotype (Art
9.3). A more interesting point is whether the fragment remains part of the
"original material" (Art 9 Note 2).  Presumably this is all a matter of size and representativeness? A bit of a tree selected for a herbarium sheet is different from a moss packet containing maybe a thousand whole plants.

  As I understand it (I may be out of date here), an isotype is a 'duplicate' of a holotype (or isosyntype, of a syntype), e.g. as in mosses when an original type collection is split into several packets for distribution to various institutions to make material more accessible, and to guard against disasters such as fire or war.

  But of course biological ‘duplicates’ may prove to be nothing of the sort, as many moss collections, whilst appearing macroscopically uniform, consist of more than one species. Some moss protologues have evidently been based on a fragment growing amongst another similar species, causing initial confusion that some error might have been made.  Splitting a packet like this would presumably not produce syntypes. Indeed splitting any packet would mean that the actual dissected specimen upon which the protologue was based (assuming that the bits were not carefully replaced and indicated), might be in only one packet, or in none of them. And for dioicous species, some isotypes might contain only one sex -- but then so might an unsplit holotype -- does this matter?

Sean Edwards, Vine Cottage, The Street, Thursley, Surrey GU8 6QF, UK
sean.r.edwards at btinternet.com
tel: 01252-702-890 cell: 07768-706-295

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