Morphological variability in Melampyrum ( Orobanchaceae )

1. Morphological variability in Melampyrum (Orobanchaceae) Milan Štech Faculty of Biological Sciences University of South Bohemia Czech Republic

2. GenusMelampyrum • almost 40 species in northern hemisphere • large morphological variation especially at infraspecific level • the indistinct species limits in some groups • “seasonal variation” – the most conspicuous phenomenon at the intraspecific level • important fetotypic plasticity, influence of host plant

3. Interspecific level Melampyrum nemorosum group

4. M. nemorosum group • nearly one half of the genus´s species • species delimitation is based predominantly on the calyx indumentum, calyx teeth length, bract shape and bract colour, corolla length and corolla shape • but • characters indicated for individual species do not correspond to reality sometimes • both infra- and interpopulation variation in these taxa are large • populations with intermediate characters occur often

5. Example M. subalpinum / M. bohemicum • many nomenclatorical and taxonomical mistakes • originally described as M. nemorosum var. subalpinum by Juratzka from the northeastern border of the Alps. • Kerner included in your species M. subalpinum (Juratzka) Kerner plants from Romania, which he himself described as M. bihariense later • Beck distinguished two types of M. subalpinum • M. subalpinum s. str. with wide leaves • M. angustissimum with narrow leaves • Kerner described M. bohemicum from the Czech Republic, but his diagnostic characters distinguish M. bohemicum from M. subalpinum s. str. and not from M. angustissimum

6. Diagnostic characters according to the Flora Europaea

7. Study • 26 morphological characters were studied in 15 populations of M. bohemicum, M. angustissimum, M. subalpinum s. str., and M. nemorosum. • Differences in indicated diagnostic charactersbetween M. bohemicum and M. angustissimum were not confirmed. M. bohemicum comprises a part of larger variation of populations of M. angustisimum. • M. subalpinum s. str. differs from both types and resembles M. nemorosum in some characters

8. Hybridization hypothesis • intermediate position of M. subalpinum s. str. between M. angustissimum and M. nemorosum • large variation range in several characters among individual populations of M. subalpinum s. str. • distribution area of M. subalpinum s. str. possibility of old introgressive hybridization between M. nemorosum and M. angustissimum

9. 0 = without capsule 1 = regular capsule 2 = aborted capsule Hybridization hypothesis • intermediate position of M. subalpinum s. str. between M. angustissimum and M. nemorosum • large variation range in several characters among individual populations of M. subalpinum s. str. • distribution area of M. subalpinum s. str. possibility of old introgressive hybridization between M. nemorosum and M. angustissimum • hybridization experiments indicate a possibility of successful crossing between M. bohemicum and M. nemorosum despite apparent reproductive barriers

10. Melampyrum sylvaticum group

11. M. saxosum M. herbichii M. sylvaticum M. sylvaticum group • problem • three taxa at the specific level are usually distinguished • two taxa consider to be endemic in the Eastern and Southern Carpathians but occurrence records originate from other regions too • study • 17 morphological characters were studied in 25 populations of M. sylvaticum in Central Europe • RAPD markers were studied in 10 populations as a support of morphological study

12. Discriminant Analysis– Canonical scores of individual plants on the discriminant axis. Results • M. herbichii seems not to be restricted in the Eastern and Southern Carpathians • Populations of M. sylvaticum agg. from the Western Carpathians and Sudeten Mts. seem to be closer to M. herbichii based on the RAPD markers, but they are polymorphic and often similar to the M. sylvaticum s. str.from the morphological point of view • But problem is more comlex and needs further study

13. Infraspecific level

14. Seasonal variation • traditionally evaluated as the most important taxonomic character at this level • different populations of one species flower in different periods of the year • in addition to the flowering period so-called “seasonal characters ” vary in different populations of one species

15. Example M. pratense • probably the most variable species of genus • many infraspecific taxa were described based on seasonal characters mainly • study • 11 morphological characters were studied in 90 populations in Central Europe • changes in seasonal characters over the flowering period in particular populations and influence of enviromental factors were studied too

16. Positions of individual plants in the ordination space of PCA of population samples. Two population examples are marked. Results • variation of “seasonal characters”is often limited by enviromental factors, which determined vegetation period length • Studied population form a very homogeneous reticulate pattern. Delimitation of intraspecific taxa based on the seasonal characters is impossible and would be artificial. • Populations of Melampyrum pratense break up into diverse “regional types” over all the distribution area. These types are characterised by a specific combination of seasonal characters, but also by other characters (the most conspicuous one is the flower colour). • Taxonomic description of these “regional types” is not much important, but processes generating this variation are worth of further study.

17. Canonical discriminant analysis of plants of Melampyrum nemorosum. Frequency distribution of specimens along the canonical variable Example M. nemorosum • 11 “seasonal characters ” were studied in 44 populations • changes in seasonal characters over the flowering period in particular populations and influence of enviromental factors were studied too • Results • significant contrast were found in the seasonal variation pattern by comparison to M. pratense • two seasonal taxa can be distinguished based studied morphological characters – early, late • difference in habitat recquirements • Polytopic origin of early type is supposed

18. Chance for further study • study of the hybrifization hypothesis by molecular methods • revision of other confused taxa from the Melampyrum nemorosum group • origin of seasonal types by individual species • study of important “nonseasonal characters” at the infraspecific level (e. g. bract shape by M. pratense) • phylogeographical study of selected species • genus phylogeny • …