GIN4843/20 Mesocyparis beringiana (Golovneva) McIver et Aulenback  

Notes

Figured in Moiseeva (2012), Plate 4, Fig. 11.

 

Locality

Amaam Lagoon Locality 1.

 

Description

From Moiseeva (2012) (p. 55)

"Available in collection the terminal generative and vegetative shoots with opposite branchlets of the second and third orders arranged in one plane. The primary shoot axes are as long as 2–5 cm and longer. As many as 6 to 11 off-shoots of the next order, which depart from axis at the angles of 30° to 40° with intervening intervals of 0.3 to 0.5 cm, are sometimes oppositely branching. Basal parts of primary shoots are usually covered with several pairs of small scale like-leaves.

The leaf arrangement is decussate. Facial leaves of the first order shoots are 3 to 5 mm long, narrow, tightly abutted on the shoot axis. Their acute apex overlaps the base of the lateral leaves. The latter are opposite, 5 to 6 mm long, falcate, with acute apex and
decurrent base. Facial leaves of secondary shoots are located in alae of lateral leaves, which are wider (up to 1 mm at the base) but shorter (2–4 mm long) than on the first order shoots, slightly falcated along the off shoot axis, with subulate apex. Facial carinate leaves of rhomboid shape with median keel are 2–3 long and 1.5–2.0 mm wide; their acuminated apex overlaps the divergence node of higher lateral leaves. Shoots of the
third order also originate in alae of lateral leaves on the second order shoots and are of similar morphology. In general they are shorter (up to 0.5–0.6 cm long), having only two three nodes.

Generative shoots preserved fragmentarily are up to 2.5–3.0 cm long. In their middle part there are several nodes with opposite sessile seed cones (one two pairs per a node). Intervals between the nodes as wide as 4–5 mm in the lower part of shoots decrease in their higher parts. In the basal part below cones, there are several pairs of connivent scale-like leaves similar to those of the vegetative shoots. In morphology of their upper parts, vegetative and generative shoots are similar, although smaller leaves of the latter are poorly preserved.

Small rounded to ovate cones are 2–4 mm in diameter. Two cone scale pairs are in pairwise opposite arrangement. In the upper pair, scales are more developed and thicker. On the dorsal surface of each scale closer to its apex there are umbo. Scales of the lower pair preserved fragmentarily are comparable in size or smaller than scales of the upper pair."

Remarks

From Moiseeva (2012) (p. 55)

"Holotype: BIN RAS, no. 967/199, seed cones and vegetative shoots; Koryak Upland, Velikaya River basin, Gornaya River; Rarytkin Formation, Maastrichtian–Danian (Golovneva, 1988, pl. II, fig. 8)."