What is Circinate vernation in Cycas?
What is Circinate vernation in Cycas?
Circinate vernation is the manner in which a fern frond emerges. As the fern frond is formed, it is tightly curled so that the tender growing tip of the frond (and each subdivision of the frond) is protected within a coil.
Is Circinate venation found in Cycas?
This type of vernation is also seen in Cycas, the only genus that is recognized in the family Cycadaceae where the leaves grow directly from the trunk. Circinate vernation is found in these new leaflets.
What is Circinate vernation give example?
Solution : Young leaves of Pinus remain coiled like a spring and open slowly from the base upwards as they mature. This is called circinate vernation.
What is function of Circinate vernation?
Circinate vernation is a term used to describe the development of the fern fiddlehead into a frond. Because plants grow apically, it is important to protect the apical meristems in growing organs (as we have seen in both axillary and terminal buds with the evolution of bud scales).
Where Circinate vernation is found?
fern leaves
When the leaf is rolled from the apex towards the base like the tail of a dog, is called circinate vernation. It is found in fern leaves.
What is Circinate vernation Class 11?
Circinate venation refers to the emergence of new leaves in ferns by unrolling from a tight coil. The coiled frond that emerges initially is termed a fiddlehead or crozier. This coiled structure protects the tender tips of the leaves.
What plants use Circinate vernation?
application to ferns In most ferns, vernation is circinate; that is, the leaf unrolls from the tip, with the appearance of a fiddlehead, rather than expanding from a folded condition.
What is Circinate leaf?
circinate (not comparable) (botany) Used of leaves or similar parts that are coiled on themselves from the apex toward their base. (medicine) Round or ring-shaped, particularly with distinct margins forming some sort of motive; annular.
What plants Circinate vernation?
The circinate vernation is the characteristic feature of ferns. It refers to
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How do you pronounce Circinate vernation?
- Phonetic spelling of circinate vernation. cir-ci-nate ver-na-tion. circinate vernation. cir-cin-ate ver-na-tion.
- Meanings for circinate vernation.
- Translations of circinate vernation. Spanish : cercenados vernation. Arabic : دائرية vernation.
What does Blennorrhagica mean?
: a disease that is characterized by a scaly rash especially on the palms and soles and is associated especially with Reiter’s syndrome. — called also keratoderma blennorrhagicum.
Where do we see Koebner phenomenon?
Koebner phenomenon can develop in any anatomic site, including in classic areas of psoriatic involvement and in regions that are usually spared, such as the face.
Who discovered Reiter’s syndrome?
Reiter’s syndrome, now known as inflammatory arthritis, was named after Hans Conrad Julius Reiter, a doctor who did his experiments at Buchenwald, a concentration camp where his experiments killed over 250 people.
Is Reiter’s syndrome genetic?
The cause of reactive arthritis is still unknown, but research suggests the disease is caused, in part, by a genetic predisposition: Approximately 75% of those with the condition have a positive blood test for the genetic marker HLA-B27.
What is the Koebner effect?
The Koebner phenomenon describes the formation of skin lesions on parts of the body where a person doesn’t typically experience lesions. This is also known as an isomorphic response. It’s long been associated with skin conditions such as psoriasis and vitiligo.
What are the uses of Cycas circinalis?
The juice obtained from young leaves of Cycas circinalis is used in skin diseases, vomiting of blood and stomach disorders. 4. The decoction of young red seeds of C. circinalis is used as a purgative and emetic.
What does Cycas revoluta ovules look like?
The ovules are green when young but at maturity they are fleshy and bright orange or red-coloured structures. The upper, conical sterile part of the megasporophyll is pinnately divided in Cycas revoluta (Fig. 8.40), C. pectinata (Fig. 8.41 B) and C. siamensis (Fig. 8.41 A).
Is Cycas revoluta an evergreen?
It is an evergreen plant. In India Cycas is represented by six species— C. revoluta, C. pectinata, C. siamensis, C. beddomei, C. rumphiand C. circinalis. Cycas revoluta is the most commonly cultivated species of Indian gardens.
What is the difference between Charcot-Marie-Tooth (C) revoluta and C circinalis?
In C. revoluta and C. beddomei the wings are curved downward or revoluted at the margins but in C. circinalis, C. rumphii, C. pectinata and C. siamensis the margins are flat. Epidermis is the outermost layer consisting of thick-walled cells. It is surrounded by a thick layer of cuticle.
