Spontaneous Hybridization between Pinus mugo and Pinus sylvestris at the Lithuanian Seaside: A Morphological Survey

Table 2

Key-traits separating P. mugo spp. uncinata and P. sylvestris. An intermediate value of a trait was scored as 0.5. The weights were used in calculating of weighted score sum (WSS).

Trait (abbreviation)	WSS weight adult	WSS weight young	Typical P. mugo subsp. uncinata	Typical P. sylvestris
			Score = 0	Score = 1
(1) Bark of the upper stem and main branches (BARK)	0.2	0.1	Fissured (small hard shells); grayish black	Peeling off in thin reddish brown flakes; dark brawn
(2) Needle colour (NEEDLE)	0.3	0.4	Fresh green	Blue green (glaucous)
(3) Cone apophysis (APOPH)	0.1	—	Hooked; blackish brown to brown; shiny	Flat; straw; dull;
(4) UMBO	0.05	—	Bordered by black or gray zone	Not bordered
(5) Symmetric cones (CONSYM)	0.05	—	No	Yes
(6) Tip of stem unit scale on the shoot bends backwards (TIPSU)	0.05	0.2	Yes	No
(6) Shoots of the previous year (SHOOT)	0.2	0.2	Grayish black; dark gray	Straw brawn
(7) Needle density on shoot (NDENSE)	0.05	0.1	High	Low
Needle anatomy (not used in WSS)
Index of stomata rows (ROWINDEX)	—	—	High	Low
Number of stomata (STOMEAN) (mean of the estimates in two rows)	—	—	Low	High