Stem has the function of transporting nutrients and water and supporting leaves, flowers and fruits in a certain space. Some stems also have the functions of photosynthesis, nutrition storage and reproduction.
When the stem grows, the terminal bud grows slowly, or withers earlier, or is a flower bud. The axillary bud below the terminal bud develops rapidly to replace the terminal bud, and so on, becoming the trunk.
Extended data:
morphological character
Saussurea involucrata is a perennial herb of Saussurea, with a height of 15-35cm. The rhizome is thick and the neck is surrounded by most brown leaves. Stems stout, base 2-3 cm in diameter, glabrous.
Dense leaves, sessile basal leaves and stem leaves, oval or ovoid leaves, length 14 cm, width 2-3.5 cm. The tip is blunt or sharp, the base is downward, the edge has sharp teeth, and both sides are hairless; The uppermost leaf bract is leaflike, membranous, pale yellow, broadly ovoid, 5.5-7 cm long and 2-7 cm wide, surrounding the raceme, with sharp teeth at the edge.
There are 10-20 heads, clustered into spherical racemes at the top of the stem, with no pedicels or short pedicels. The involucre is hemispherical with a diameter of 65438 0 cm; The involucral bracts have 3-4 layers, with purple-brown edges, sharp apex, sparsely villous outer layer, oblong outer layer, length 1. 1cm, width 5mm, middle layer and inner layer lanceolate, length 1.5- 1.8cm and width 2 mm.. The floret is purple, with a length of 1.6 cm, a tube length of 7 mm and a eaves length of 9 mm.
Achene oblong, 3 mm long. The crown hair is dirty white and has two layers, the outer layer is small and rough, 3 mm long, and the inner layer is long and feathery, with a length of 1.5 cm. The flowering and fruiting period is from July to September.
References:
Baidu encyclopedia-snow lotus