Premise of the study:Constructing complete, accurate plant DNA barcode reference libraries can be logistically challenging for large-scale floras. Here we demonstrate the promise and challenges of using herbarium collections for building a DNA barcode reference library for the vascular plant flora of Canada.Methods:Our study examined 20,816 specimens representing 5076 of 5190 vascular plant species in Canada (98%). For 98% of the specimens, at least one of the DNA barcode regions was recovered from the plastid loci rbcL and matK and from the nuclear ITS2 region. We used beta regression to quantify the effects of age, type of preservation, and taxonomic affiliation (family) on DNA sequence recovery.Results:Specimen age and method of preservation had significant effects on sequence recovery for all markers, but influenced some families more (e.g., Boraginaceae) than others (e.g., Asteraceae).Discussion:Our DNA barcode library represents an unparalleled resource for metagenomic and ecological genetic research working on temperate and arctic biomes. An observed decline in sequence recovery with specimen age may be associated with poor primer matches, intragenomic variation (for ITS2), or inhibitory secondary compounds in some taxa.
Plant identification in response to poison control inquiries poses problems for medical staff and botanists alike. Lack of a specimen for verification combined with a limited description by an untrained lay person hinders confident identification of the plant. In view of these problems a computer identification system has been developed for use in answering poison control calls. A database has been compiled for 103 common houseplants described in lay terms, with respect to 56 features each possessing a number of possible states. The database is used with the MS-DOS polyclave program ONLIN6. Identifications are made by entering data for available features, so as to eliminate taxa until a single taxon remains. This system has been used in 112 mock calls in which the resulting identification could be checked. These trials resulted in correct identifications 65% of the time. Errors were attributed primarily to problems related to translation of character states into lay terminology. Revision of the database is planned that will eliminate these problems. Use of the system by hospital personnel is recommended only after graphics screens have been added to the database, and where staff have been specially trained in botanical terminology and in use of the ONLIN6 program.
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