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Types of identification methods

Types of identification methods. Diagnostic (dichotomous) keys: Bracketed or numerical keys Indented keys Multi-access keys or polyclaves Comparison methods Electronic keys. Dichotomising key. Dichotomous key - bracketed. 1. Leaves mealy beneath; flowers lilac or purple………….…...2

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Types of identification methods

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  1. Types of identification methods • Diagnostic (dichotomous) keys: • Bracketed or numerical keys • Indented keys • Multi-access keys or polyclaves • Comparison methods • Electronic keys

  2. Dichotomising key

  3. Dichotomous key - bracketed 1. Leaves mealy beneath; flowers lilac or purple………….…...2 + Leaves not mealy beneath; flowers yellow………………......3 2. Leaves crenulate; flowers lilac, heterostylous; corolla lobes distant; calyx teeth ± acute; capsule cylindrical, much exceeding calyx….....................................................................1. farinosa + Leaves not crenulate; flowers blue-purple, not; corolla lobes contiguous; calyx teeth obtuse; capsule ovoid, slightly exceeding calyx…………… ……………………….…..2. scotica 3. Scape distinct; pedicels finely pubescent; limbe of corolla concave, rarely exceeding 20mm diam…………………..……4 + Scape 0 or nearly so; pedicels with shaggy hairs; limb of corolla flat, usually more than 30mm……………………….…..5. vulgaris 4. Calyx uniformerly pale green; corolla with folds in the throat; fruit ovoid, enclosed in the calyx……………………………….3. veris + Calyx with midribs conspicuously darker green than the remainder; corolla without folds in the throat; fruit oblong- ovoid, exceeding calyx……………………………………….…..4. elatior leads couplet

  4. Dichotomous key – indented(new numbers) 1. Leaves mealy beneath; flowers lilac or purple 2. Leaves crenulate; flowers lilac, heterostylous; corolla lobes distant; calyx teeth ± acute; capsule cylindrical, much exceeding calyx…...........................................................................1. farinosa 2. Leaves not crenulate; flowers blue-purple, not; corolla lobes contiguous; calyx teeth obtuse; capsule ovoid, slightly exceeding calyx………………..……………………………..2. scotica 1. Leaves not mealy beneath; flowers yellow 3. Scape distinct; pedicels finely pubescent; limbe of corolla concave, rarely exceeding 20mm diam. 4. Calyx uniformerly pale green; corolla with folds in the throat; fruit ovoid, enclosed in the calyx……………………………….3. veris 4. Calyx with midribs conspicuously darker green than the remainder; corolla without folds in the throat; fruit oblong- ovoid, exceeding calyx……………………………………….…..4. elatior 3. Scape 0 or nearly so; pedicels with shaggy hairs; limb of corolla flat, usually more than 30mm………………………..…..5. vulgaris leads couplet couplet

  5. Dichotomous key – indented(repeated numbers) 1. Leaves mealy beneath; flowers lilac or purple 2. Leaves crenulate; flowers lilac, heterostylous; corolla lobes distant; calyx teeth ± acute; capsule cylindrical, much exceeding calyx…...........................................................................1. farinosa 2. Leaves not crenulate; flowers blue-purple, not; corolla lobes contiguous; calyx teeth obtuse; capsule ovoid, slightly exceeding calyx………………..……………………………..2. scotica 1. Leaves not mealy beneath; flowers yellow 2. Scape distinct; pedicels finely pubescent; limbe of corolla concave, rarely exceeding 20mm diam. 3. Calyx uniformerly pale green; corolla with folds in the throat; fruit ovoid, enclosed in the calyx……………………………….3. veris 3. Calyx with midribs conspicuously darker green than the remainder; corolla without folds in the throat; fruit oblong- ovoid, exceeding calyx……………………………………….…..4. elatior 2. Scape 0 or nearly so; pedicels with shaggy hairs; limb of corolla flat, usually more than 30mm………………………..…..5. vulgaris leads couplet couplet

  6. Dichotomous key – indented(letters, symbols, etc.) A. Leaves mealy beneath; flowers lilac or purple B. Leaves crenulate; flowers lilac, heterostylous; corolla lobes distant; calyx teeth ± acute; capsule cylindrical, much exceeding calyx…...........................................................................1. farinosa BB. Leaves not crenulate; flowers blue-purple, not; corolla lobes contiguous; calyx teeth obtuse; capsule ovoid, slightly exceeding calyx………………..……………………………..2. scotica AA. Leaves not mealy beneath; flowers yellow C. Scape distinct; pedicels finely pubescent; limbe of corolla concave, rarely exceeding 20mm diam. D. Calyx uniformerly pale green; corolla with folds in the throat; fruit ovoid, enclosed in the calyx……………………………….3. veris DD. Calyx with midribs conspicuously darker green than the remainder; corolla without folds in the throat; fruit oblong- ovoid, exceeding calyx……………………………………….…..4. elatior CC. Scape 0 or nearly so; pedicels with shaggy hairs; limb of corolla flat, usually more than 30mm………………………..…..5. vulgaris leads couplet couplet

  7. Dichotomous key – indented(continuous text) A. Leaves mealy beneath; flowers lilac or purple - B. Leaves crenulate; flowers lilac, heterostylous; corolla lobes distant; calyx teeth ± acute; capsule cylindrical, much exceeding calyx 1. farinosa - BB. Leaves not crenulate; flowers blue-purple, not; corolla lobes contiguous; calyx teeth obtuse; capsule ovoid, slightly exceeding calyx 2. scotica - AA.Leaves not mealy beneath; flowers yellow - C. Scape distinct; pedicels finely pubescent; limb of corolla concave, rarely exceeding 20mm diam. - D. Calyx uniformerly pale green; corolla with folds in the throat;fruit ovoid, enclosed in the calyx 3. veris - DD. Calyxwith midribs conspicuously darker green than theremainder; corolla without folds in the throat; fruit oblong-ovoid, exceeding calyx 4. elatior - CC. Scape 0 or nearly so; pedicels with shaggy hairs; limb of corolla flat, usually more than 30mm 5. vulgaris couplet

  8. Indented versus bracketed keys Indented (+) • Groups taxa Indented (-) • Leads may be far apart • Less economical on space • Less intuitive? Bracketed (+) • Leads next to each other • More economical on space • More intuitive? Bracketed (-) • Doesn’t group taxa

  9. Definitions • Character – a fundamental item of descriptive information Characters can be: • Qualitative – eg colour, hairs etc • Quantitative discontinuous – eg petals number • Quantitative continuous – eg leaf length • State/value - the data recorded for a character • Data matrix – a table of character information

  10. Contructing a dichotomous key • Try to split taxa into even groups • Avoid “chipping” • Characters should be easily seen • Characters should be reliable and constant • Contrasting characters must contrast – not overlapping • If possible use several contrasting characters in each couplet – ideally vegetative, flowering and fruiting • Each lead of the same couplet should begin with the same word • Should be dichotomising (forking); triplets avoided? • Avoid - Leaves large leaves small • Avoid “not as above” – restrict to major differences

  11. Data matrix

  12. Contructing a key • Try to split key evenly • Avoid “chipping” • Characters should be easily seen • Characters should be reliable and constant • Contrasting characters must contrast – not overlapping • If possible use several contrasting characters in each couplet – ideally vegetative, flowering and fruiting • Each lead of the same couplet should begin with the same word • Should be dichotomising (forking); triplets avoided? • Avoid - Leaves large leaves small • Avoid “not as above” – restrict to major differences

  13. Flora of Bhutan

  14. Contructing a key • Try to split key evenly • Avoid “chipping” • Characters should be easily seen • Characters should be reliable and constant • Contrasting characters must contrast – not overlapping • If possible use several contrasting characters in each couplet – ideally vegatative, flowering and fruiting • Each lead of the same couplet should begin with the same word • Should be dichotomising (forking); triplets avoided? • Avoid - Leaves large leaves small • Avoid “not as above” – restrict to major differences • If necessary key out more than once

  15. Multi-access keys

  16. Data matrix

  17. Character Character stateCharacter state code • Leaf surface • Mealy A • Non mealy B • Flower colour • Lilac A • Purple B • Yellow C • Leaf margin • Crenulate A • Entire B • Scape • Present A • Absent B • Calyx colour • Green A • Green/white B • White C Unknown plant Leaves not mealy B Flowers yellow C Leaf margin ? Scape distinct A Calyx geen A

  18. P. farinosa A A A B B P. scotica A A B B C P. veris B C B A A P. elatior B C B A B P. vulgaris B C B B C Unknown plant B C ? A A

  19. Comparison methods • Check in herbarium • Go through literature (Floras/Monographs) • descriptions • illustrations • maps • Other eg. AIDGAP willow key

  20. Illustrated Keyseg Ethnoflora of Soqotra

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