Question

haplostele is present in ___​

Answer 1

Answer:

psilotum stem

Explanation:

Answer 2

ANSWER :-

Examples of species or cases where haplosteles are present are as follows- 

• Selaginella kraussiana,
• Rhynia, Horneophyton,
• Cooksonia, etc.

Extra Information-

• Protostele is referred to as the most primitive type of stele and all of the other kind of steles have been derived from it. -

1. In the case of this kind of stele, the pith is completely absent. 
2. This primitive type of stele is found in Lygodium, Psilotum, Selaginella, etc.

• Protostele consists of four further different types within itself. The types are as follows-

1. Haplostele- Here, solid round central core of xylem is surrounded by phloemand pericycle.
2. Actinostele- Here, central xylem is star shaped with radiating arms and phloem is present in separate patches. Examples of species or cases where actinosteles are found are as follows- Asteroxylon, Lycopodium serratum, Psilotum, etc.
3. Plectostele- Here, xylem is present in the form of separate plates and phloem is present between these xylem plates. Example of species or cases where plectosteles are found are as follows- Lycopodium clavatum and Lycopodium volubile.
4. Mixed Protostele- Here, xylem is present in the form of discrete units embedded in phloem. Example of species or case where mixed protostele is found is as follows- Lycopodium cernuum.