Макарова, О. А. Фенологический атлас растений / Н. В. Поликарпова, О. А. Макарова ; М-во природ. ресурсов и экологии Рос. Федерации, Федер. гос. бюджет. учреждение «Гос. природ. заповедник «Пасвик» ; [худож.: Хохлов В. А. ; пер.: Кислова О. С.]. - Рязань : Голос губернии, 2016.

5. FLOWERING ONSET International phase code BBCH 60 (Growing stage.., 2001; Meier et al., 2009) Phase description The day of flowering onset is when fully open corollas are found on 10% of plants in the transect. When monitoring inflorescences (rowan, rosebay willowherb, Labrador tea, yarrow), flowering onset is recorded on the day when the first blooming flowers (with petals open) appear within inflorescences. Some plants begin flowering before leaves have emerged (goat willow, alder), others simultaneously with leaf unfolding (birch, some willows), third ones after leaf-out (chickweed-wintergreen, dwarf cornel, wood cranesbill, rowan). In wind-pollinated plants (birch, aspen, spruce, pine) flowering is deemed to have begun when branches shed pollen when shaken by wind or hand. In insect-pollinated plants, flowering onset is the phase when anthers emerge. In most species a sign of flowering is emergence of stamens from male inflorescences (usually on the sunny side) and dehiscence of anthers. An indirect sign of flowering onset is the arrival of insects at inflorescences. In some years, especially when a prolonged period of hot and dry weather is followed by abundant rainfall, the flower buds set in the current year may awaken ahead of time (in late summer and autumn) and a second bloom happens. Secondary flowering is a poorly studied phenomenon. Further info Fenolog. rgo.ru: Flowering onset in insect-pollinated woody plants that produce flowers with well-developed and brightly colored perianth (rowan, bird cherry, hawthorn) is to be recorded on the day when the first flowers with corolla completely open appear in the crown on the first 2-3 specimens. For wind-pollinated plants, including all conifers and many deciduous trees and shrubs (birch, alder, aspen, etc.), flowering onset is timed to anthesis: in the plants that begin to flower shaking of branches bearing male inflorescences, gusts of wind or tapping anthers with a 2 1 2 ......................................................................................................A phenological at.as of plants