3.1 Life cycle
Almost all F1 plants from the mountains bordering Bohemia, the Arlberg mountain and the offspring of the specimen REN#5 from the Engadin developed inflorescences already in the second year. In contrast, the offspring of the other specimens from the Engadin, except for two individuals, formed only leaf rosettes (Fig. 1; tab. 3, second column). For unknown reasons the growth conditions were no more optimal in the author’s garden, despite climatic parameters rather favourable to the species (foothills of the Bavarian Alps, 587 m sea level). The plants showed only poor growth, did not flower in the third and developed only a single inflorescence in the fourth year (tab. 3).
3.2 Vegetative features
If only the specimens collected in the field are considered, the length-width ratio of the basal leaf blades allows to divide the studied populations into three groups (tab. 1). The plants from the Czech Republic (Krkonoše mountains, Ještěd mountain, Bohemian Forest) have broad blades (L/W-B ca. 2.5) and may therefore be assigned, in accordance with the opinion being held in the Czech literature (e. g. Kubát 1990), to subsp. sourekii. The plants from the Bavarian Forest and the Engadin with L/W-B ca. 3.5 correspond to the nominate form (Castroviejo et al. 1990), and the Arlberg population with L/W-B > 4 to the (taxonomical yet not described) Southeast Scandinavian group in the sense of Holm & Korpelainen (1999).
As tab. 2 shows, these features are superimposed by the developmental stage of the plants. In the F1 generation, the parental differences appear only in the second year, while the vegetative rosettes of the first year, as well as the poorly growing plants of the fourth year, are characterized by broader leaves. This finding provides a possible explanation for the leave shape of P specimen RAT#1d, which deviates from that of the other Arlberg plants by its much smaller L/W-B (tab. 2). The specimen consists of a leaf rosette formed during the current vegetation period, which is connected to the dead fruiting stalk (fig. 2). Obviously, such a secondary innovation shoot tends to get broader leaves in the same way as a first year’s vegetative individual.
Tab. 1 Morphological features of basal leave laminas, valves, and tubercles; populational averages comprising the specimens collected in the field
Population
|
L/W-B
|
Valve length [mm]
|
Valve width [mm]
|
L/W-V
|
Tubercle index
|
Tubercle length [mm]
|
Tubercle width [mm]
|
Krkonoše mountains
(RKr#xx)
|
2.3
|
4.5
|
5.2
|
0.88
|
4
|
0.7
|
0.4
|
Bohemian Forest
(RSp#xx)
|
2.3
|
5.8
|
6.2
|
0.94
|
2
|
0.6
|
0.4
|
Bavarian Forest
(RAr#xx)
|
3.5
|
5.1
|
5.8
|
0.87
|
1
|
0.6
|
0.3
|
Ještěd mountain
(RJ#xx)
|
2.7
|
5.0
|
4.8
|
1.05
|
0
|
-
|
-
|
Upper Engadin
(REN#xx)
|
3.6
|
6.4
|
6.6
|
0.97
|
0 (REN#6)
|
-
|
-
|
4 (other)
|
1.0
|
0.6
|
St. Anton am Arlberg
(RAT#xx)
|
4.2
|
4.7
|
5.2
|
0.91
|
3 (RAT#4)
|
0.8
|
0.3
|
0 (other)
|
-
|
-
|
Tab. 2 Basal leave laminas of the cultivated F1 plants and the corresponding P specimens
Population
P specimen (number of F1 plants)
|
L/W-B (P)
|
L/W-B (F1) 12. 8. 2019
|
L/W-B (F1) 22. 5. 2020
|
L/W-B (F1) 11. 5. 2021
|
L/W-B (F1) 12. 5. 2022
|
Krkonoše mountains
RKr#1 (4)
|
2.8
|
1.8
|
2.2
|
-
|
-
|
Bavarian Forest
RAr#1 (7)
|
3.5
|
2.6
|
3.9
|
-
|
-
|
Bavarian Forest
RAr#2a (5)
|
1.7
|
2.4
|
3.2
|
-
|
-
|
Ještěd mountain
RJ#1 (7)
|
1.9
|
2.4
|
3.8
|
-
|
-
|
Upper Engadin
REN#2b (7)
|
3.3
|
2.5
|
3.5
|
3.5
|
2.8
|
Upper Engadin
REN#4b (6)
|
3.2
|
2.5
|
3.2
|
3.4
|
2.7
|
Upper Engadin
REN#5 (6)
|
3.8
|
3.8
|
4.8
|
-
|
-
|
Upper Engadin
REN#8 (7)
|
4.0
|
2.5
|
3.1
|
3.4
|
3.0
|
St. Anton am Arlberg
RAT#1a (7)
|
4.1
|
3.3
|
4.9
|
-
|
-
|
St. Anton am Arlberg
RAT#1d (7)
|
2.7
|
2.9
|
4.4
|
-
|
-
|
St. Anton am Arlberg
RAT#5 (7)
|
4.5
|
2.6
|
3.8
|
-
|
-
|
3.3 Generative features
In the Alps, the specimens from the Engadin are distinguished by their large valves which – except in the single specimen REN#6 – always bear tubercles. In contrast, the valves of the Arlberg plants are significantly smaller and, again except for a single specimen (RAT#4), always lack tubercles (tab 1 and 3, fig. 3). These differences persist - more or less - in the F1 generation (tab. 3), hence obviously are genetically fixed. Taking into account the above-mentioned leaf traits it therefore can be concluded that the population of the Arlberg mountain, which exists at least since the early 1990ies (Willner 1994), originated by a separate introduction instead, as supposed earlier (Sonnberger 2018), by migration from the Engadin down the upper Inn valley. This can be seen also from the aspect of the stands above St. Anton. The plants concentrate at 1850 m asl around the cable way building complex “upper terminus Gampenbahn / lower terminus Kapallbahn”, from which they descend ca. 100 m downhill along the Gampenbahn cableway line. Here we are obviously dealing with the scheme described by Rechinger (1990), i.e., an isolated introduction followed by subsequent expansion.
The Valves of the plants from Ještěd mountain differ from those of all other examined populations by invariably lacking tubercles and a larger length-width ratio. As can be seen from tab. 3, the first trait is inherited unalteredly (tubercle index = 0 in P as well as F1), while the latter is varying between the generations (L/W-V (P) = 0.95; L/W-V (F1) = 1.02; fig. 4). On the other hand, the plants from Krkonoše mountains and the Bavarian Forest differ in L/W-B and tubercle index, again as well in the P as in the F1 generation (tab. 2 und 3). It can therefore be assumed that altogether three genetically discrete populations occur in the mountains bordering Bohemia, fig.5.
Tab. 3 Generative features of the cultivated F1 plants and the corresponding P specimens
Population
P specimen
|
Fructifying plants 1. 8. 2020
|
Valve length [mm]
|
Valve width [mm]
|
L/W-V
|
Tubercle index
|
Tubercle length [mm]
|
Tubercle width [mm]
|
|
|
P
|
F1
|
P
|
F1
|
P
|
F1
|
P
|
F1
|
P
|
F1
|
P
|
F1
|
Krkonoše mountains
RKr#1
|
4 of 4
|
4.7
|
4.5
|
5.4
|
4.9
|
0.88
|
0.91
|
4
|
4
|
0.7
|
0.9
|
0.3
|
0.3
|
Bavarian Forest
RAr#1
|
7 of 7
|
5.6
|
4.7
|
6.2
|
5.2
|
0.90
|
0.90
|
2
|
2
|
0.6
|
0.5
|
0.2
|
0.2
|
Bavarian Forest
RAr#2a
|
5 of 5
|
4.5
|
4.9
|
5.4
|
5.2
|
0.84
|
0.94
|
0
|
1
|
-
|
0.7
|
-
|
0.2
|
Ještěd mountain
RJ#1
|
7 of 7
|
4.3
|
5.1
|
4.6
|
5.0
|
0.95
|
1.02
|
0
|
0
|
-
|
-
|
-
|
-
|
Upper Engadin
REN#2b
|
1 of 7
|
6.3
|
6.0
|
6.9
|
6.1
|
0.92
|
0.98
|
4
|
3
|
0.8
|
0.7
|
0.5
|
0.4
|
25.7.2022
(1 plant)
|
5.2
|
5.3
|
0.99
|
4
|
1.1
|
0.7
|
Upper Engadin
REN#4b
|
1 of 6
|
6.6
|
6.2
|
6.8
|
6.6
|
0.97
|
0.93
|
4
|
4
|
1.1
|
1.1
|
0.6
|
0.7
|
Upper Engadin
REN#5
|
6 of 6
|
5.7
|
5.8
|
6.1
|
6.1
|
0.93
|
0.97
|
4
|
4
|
1.7
|
1.5
|
0.9
|
0.8
|
Upper Engadin
REN#8
|
0 of 7
|
6.7
|
-
|
7.2
|
-
|
0.93
|
-
|
4
|
-
|
1.2
|
-
|
0.7
|
-
|
St. Anton am Arlberg
RAT#1a
|
7 of 7
|
4.6
|
4.9
|
5.1
|
5.5
|
0.91
|
0.89
|
0
|
1
|
-
|
0.7
|
-
|
0.3
|
St. Anton am Arlberg
RAT#1d
|
7 of 7
|
4.2
|
4.8
|
4.6
|
5.3
|
0.91
|
0.90
|
0
|
0
|
-
|
-
|
-
|
-
|
St. Anton am Arlberg
RAT#5
|
6 of 7
|
4.6
|
4.7
|
5.1
|
5.3
|
0.90
|
0.89
|
0
|
1
|
-
|
0.5
|
-
|
0.3
|
3.4 Synopsis of the morphological findings
Combining the data obtained from the original collections and the F1 cultures, the studied populations may be distinguished from each other by the following mean parameter ranges:
Population
|
Length-width ratio of the basal leaf blades on current years flowering shoots
|
Length of the valves [mm]
|
Length-width ratio of the valves
|
Proportion of flowers with one mature valve bearing a tubercle
|
Krkonoše mountains
|
2 - 3
|
4 - 5
|
0.85 – 0.95
|
>50%
|
Bavarian Forest
|
3 - 4
|
4.5 – 5.5
|
0.85 – 0.95
|
<50%
|
Ještěd mountain
|
3 - 4
|
4.5 – 5.5
|
0.95 – 1.05
|
0% (without exception)
|
Upper Engadin
|
3 - 4
|
6 - 7
|
0.90 – 1.00
|
100% (except for single individuals)
|
St. Anton am Arlberg
|
>4
|
4 - 5
|
0.85 – 0.95
|
0% (except for single individuals)
|
The values are sufficiently distinct to demonstrate that geographical separation is associated with morphological difference, which allows the conclusion that the individual populations originated by different introduction events. Unfortunately, as no ripe seeds were available, it was not possible to include the Bohemian Forest population (see tab. 1) into the cultivation experiments. In the Czech literature the plants occurring there, as well as those naturalized in the Krkonoše mountains, are assigned to a separate subsp. sourekii Kubát, which differs from the nominal taxon by broader leaves (Kubát 1990). Although this trait could be confirmed here for the collections from the Krkonoše mountains, its taxonomical relevance should be assessed against the variability of the species, and the dependence of just this character from development stage and growth conditions (see 3.2). Considering the general polymorphism of R. longifolius, a categorisation based on a single character does not seem appropriate anyway. The rank of a subspecies clearly overemphasizes the taxonomical status of subsp. sourekii as defined hitherto.