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The asexual or parthenogenetic phase, about 10 mm across, [1] develops on acorn cups of English oak Q. robur and sessile oak Q. petraea. The galls, formed of flattened projections, often enclose the immature acorn. [1] The galls first appear pink in colour and as they mature they turn red, then green and finally brown during their development.
A plant which completes its life cycle (i.e. germinates, reproduces, and dies) within two years or growing seasons. Biennial plants usually form a basal rosette of leaves in the first year and then flower and fruit in the second year. bifid Forked; cut in two for about half its length. Compare trifid. bifoliate
Galls (upper left and right) formed on acorns on the branch of a pedunculate (or English) oak tree by the parthenogenetic generation Andricus quercuscalicis.. The large 2 cm gall growth appears as a mass of green to yellowish-green, ridged, and at first sticky plant tissue on the bud of the oak, that breaks out as the gall between the cup and the acorn.
Plant embryonic development, also plant embryogenesis, is a process that occurs after the fertilization of an ovule to produce a fully developed plant embryo. This is a pertinent stage in the plant life cycle that is followed by dormancy and germination . [ 1 ]
Abscission (from Latin ab- 'away' and scindere 'to cut') is the shedding of various parts of an organism, such as a plant dropping a leaf, fruit, flower, or seed. In zoology , abscission is the intentional shedding of a body part, such as the shedding of a claw , husk, or the autotomy of a tail to evade a predator.
The margins are usually entire or toothed, and are rounded at the base. The texture of the leaves is leathery and stiff. The veins are parallel, and are sunken on the upperside and raised underneath. Leaves may begin to shed in late winter, or when new leaves emerge in spring. [7] Fruit: oblong acorn that is 1 ⁄ 2 to 1 in long. Acorns have ...
In vascular plants, the diploid sporophyte has evolved as the dominant and visible phase of the life cycle. In seed plants and some other groups of vascular plants the gametophyte phases are strongly reduced in size and contained within the pollen and ovules. The female gametophyte is entirely contained within the sporophyte's tissues, while ...
A mature female big-cone pine (Pinus coulteri) cone, the heaviest pine cone A young female cone on a Norway spruce (Picea abies) Immature male cones of Swiss pine (Pinus cembra) A conifer cone, or in formal botanical usage a strobilus, pl.: strobili, is a seed-bearing organ on gymnosperm plants, especially in conifers and cycads.