Vascular Bundle In Plants. The vascular bundles play important roles in transportation of photoassimilate, and the number, size, and capacity of vascular bundles influence the transportation efficiency. Xylem and phloem are seen as patches and they alternate each other, and occupy the different radii on the axis separated by non conductive tissue.

They are a type of complex tissue. Vascular bundle consists of xylem and phloem. The arrangement and structure of these tissues differ in different categories of vascular plants like pteridophytes, gymnosperms, monocots and dicots.

Plants From The Cretaceous Period. Other cretaceous period plants included: During the late cretaceous l evels fall to ~1,000 ppm.

The most dramatic occurrence during the cretaceous was the first appearance of flowering plants, the angiosperms!! During the late cretaceous l evels fall to ~1,000 ppm. Oxygen levels begin at ~20.5% and increase to ~22.5% by the end of the period.

Types Of Seed Plants. The two major types of seed plants are the gymnosperms (seeds in cones) and angiosperms (seeds in ovaries of flowers). Some of the cereal plant seeds are bran, wheat, rice,.

The existing species can be broken down into a few groups, including bryophytes, ferns, fern allies, and seed plants. A seed is primarily of two types. There are two seed leaves inside the dicotyledon seed.