Anatomy Of Flowering Plants

Vessels are absent in some angiosperm. In the given options, in Drimys vessels are absent. This is a homoxylous angiosperm. Other angiospermic plants which lack vessels are Brimys, Bubbia, Belliolum, Pseudowintera, Exopermum, Zygogynum, Trochodendron, Tetracentron.

Collenchyma is a specialized supporting simple permanent tissue of living cells possessing characteristically unevenly distributed thickenings of cellulose, pectin and hemicelluloses on their walls. Schleiden (1839) discovered and coined the term collenchyma. Lamellar collenchyma is characterized by deposition of heavy thickenings in the tangential than in the radial cell walls, eg, stems of Sambuscus and Raphanus.

A. Procambium is a plant tissue derived from the apical meristem which forms the vascular bundles i.e, the xylem and the phloem.
B. Intercalary meristems are residual apical meristems present at the nodes and internodes which increases the length of the plant.
C. Phellogen is also known as cork cambium which is a lateral meristem which increases the girth of the plant.
D. Apical meristem is situated at the root and shoots tip which helps in the primary growth of a planet by increasing the length of the plant.
The lateral meristem which occurs on the lateral side of the longitudinal axis stem is parallel to the longitudinal axis and are responsible for increasing the girth of a plant (secondary growth).

In dicotyledonous stem the sequences of tissues from inside to outside in its transverse section is pith, wood parenchyma, protoxylem, metaxylem, cambium, phloem, pericycle (sclerenchyma), endodermis, parenchyma (cortex), collenchyma (hypodermis), epidermis cuticle and multicellular epidermal or shoot hair.

In dicot plants, the secondary growth occurs due to the activity of the cambium. It cuts phloem on outer side and xylem on inner side of stem. It increases the heartwood area of stem which shows the presence of annual rings.