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Fig. 205 Leaf. (a) Simple leaves. (b) Compound leaves.click for a larger image
Fig. 205 Leaf . (a) Simple leaves. (b) Compound leaves.

leaf

the principal photosynthetic organ of vascular plants, which typically consists of a flattened lamina joined to the stem by a stalk or petiole, at which junction an axillary bud can be found. There are numerous types of leaves.
  1. dorsiventral leaves are held horizontally with the upper half of the lamina containing the majority of photosynthetic cells (see MESOPHYLL for diagram). Typically, the lower epidermis contains the majority of STOMATA through which gas exchange and transpiration take place. Leaf veins are usually arranged in a ‘net’ venation with principal veins called midribs. The lamina can be indented to form a ‘compound’ leaf or remain as a simple structure. See Fig. 205 . Dorsiventral leaves are typical of DICOTYLEDONS.
  2. isobilateral leaves grow erectly, with a sword-like shape and are typical of MONOCOTYLEDONS. Both epidermal surfaces contain stomata with palisade mesophyll tissue packed underneath. Isobilateral leaves have a parallel venation and are not divided into compound structures. See also KRANZ ANATOMY.
  3. centric leaves are more or less cylindrical with a central region containing the vascular bundles surrounded by mesophyll tissue. Examples are the needles of pine trees, and onion leaves.

Some leaves have special modifications. For example, water storage leaves are found in many plants living in dry conditions (e.g. cacti). In other plants the leaves are modified into tendrils for climbing (e.g. pea) while in some the leaves have become spines, e.g. gorse.

Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005

Patient discussion about leaf

Q. What happens if you leave appendicitis alone? I have symptoms of appendicitis, but I don't want to go to the hospital. What should I do? and what could happen?

A. If you have symptoms of appendicitis you should see a doctor immediately, because the major complication of an untreated appendix is rupture and infection of the entire abdomen, that can lead to generalized sepsis.

Q. Any ideas about why she leaves some food in her plate. Thank you for your visit. My daughter is 8 years old and she is a poor eater. She never wants to eat dinner even if it's her favorite dish. And then she picks it and an hour later she says that she feels hungry. She never completes her plate, always leaving a bit, no matter what we feed her. Should she be forced to eat dinner and if she doesn't, have only the dinner to eat later? Any ideas about why she leaves some food in her plate?

A. She trusts her mom. The most common reason to be like this is she knows that she will get something to eat later from her dear mom. While she shouldn't be forced to eat, she should learn that her main meal in the evening will be served at the dinner time.
Some other things that you might do to help deal with your picky eater include:
• Make sure that she isn't eating a big snack after school or filling up on juice, soda, or even milk before dinner.
• Offer her smaller portions so that there isn't as much left over on her plate.
• Don’t offer bribes or rewards for eating.
• Never talk about dieting, calories, and such, especially if she or other family members have problems with being overweight. Instead, talk about eating healthy.
• Consider not offering her anything else to eat if she misses dinner or just offer a small, healthy snack.

Mainly a visit to your Pediatrician to monitor her growth, development and eating habits would also be a good idea. Hug her now!

Q. What makes me worried that it’s really painful but might not be able to leave all of a sudden. Doctor diagnosed my son with peanut allergy after some tests. His body generates rashes and these eruptions are painful for him. I thought it big to be eczema as I heard about it, but now it is diagnosed and I am not able to decide how to avoid him of not giving peanuts and to keep him away as he likes them. Once near to me I can try to avoid to some extent, but once away to school or in playing with friends he does eat them regularly. What makes me worried that it’s really painful but might not be able to leave all of a sudden.

A. My friend’s brother does have the experience of peanut allergy. These peanuts are nutritious, but its allergy is awful. He has a clear understanding of this and avoids eating them. I too have found that he followed strict guidelines for not eating them when it was diagnosed for him. The best thing is to create some other or new foodstuff taste for him which might help him be consumed an alternative for nuts for some times and then provide with peanuts for him to regain his remembrances for the culprit he consumes. It needs to be done under your care for long time till he develops the inhibitions for nuts. You must also remember to memorize some medicine names and symptoms, so, if consumed unknowingly can explain what it is to anyone responsible nearby.

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References in periodicals archive ?
(http://www.pokemon-sunmoon.com/en-us/pokemon/brionne/) Brionne is still a Water-type monster. Its move called Leafage actually involves striking the opponent using leaves.
You always experience it when you see the surface of your sweater, of your skin, of the table in the front of you, of the lawn behind the window, when you see the leafage of a tree, sand at the beach etc.
According to the studies, leafage and brushes may serve as a barrier against airflow.
Specific areas examined are applications of laser welding in the welding of hot-rolled sheet, fatigue properties of Grade B steel casted by the resin sand process, and non-destructive testing of wire rope using magnetic flux leafage. Other topics water flow heat transfer in metal foams, applications of computer science in materials science, finite element analysis of temperature field in traction motors, and computational simulation of failures in brittle materials.
LEAFAGE If I could urge you - to take a lingering look In at your local library - to borrow a book From Brave New World - To Kill a Mockingbird This is the power of a simple written word Charles Dickens to William Shakespeare Martin Chuzzlewit to tragic King Lear George Orwell with A Clergyman's Daughter Coming up for air - but not underwater You can find books of copious classic literature A very forceful impact - of this you can be sure Comedy, tragedy and lots of drama Far more powerful than Mr Obama You'll find a sense of humour in the library staff Who are helpful no end whilst enjoying a laugh Again I urge you - to pick up this hint The power and the glory is here in print Jock Brownlee, Loxley Close, Wood End, Coventry.
Yet listening to the voice of poetry instead of the God of despair, we might feel free to ask, as poet Elizabeth Willis does in her book Meteoric Flowers, "What is your tribe and your eminent leafage, your robed rhetorical temperature?
System of plantings: cropped and natural, high and low, round and strait forms, soft and sharp leaves, plants with different leafage, branches and trunks and their groups are composed.
In transition zones, thornforests and deciduous forests intermix, although deciduous forests can be distinguished by its greater height (unbroken canopy is 10-20 m above ground), larger leafage (macrophyllous and mesophyllous taxa dominate contrasting with the microphyllous shrubs and trees that dominate thornforests), the reduced dominance of thorny and succulent plants, and by strong penetration of species, genera, and families showing a tropical distribution, including epiphytic orchids and bromeliads.
Staring at the wind-swayed leafage in the crowns of the riverside hardwoods, he didn't know exactly how he would say it, but he would call Siefert and report his discovery.
"Conrad at Twilight" (1923) is a satirical portrait of a Southern poet wallowing in his "mouldy garden," his "feet dipping in leafage and muck," who pointedly ignores the speaker's--perhaps ironic--exhortations to be manly enough to "smite an anvil, draw a sword / (See William James and Henry Ford) / And point you to a mightier goal!" (Ransom 1923, 27).
NPL has developed a methodology for crop identification and selection focusing on cauliflower crops, one of the hardest crops to measure due to the large amount of leafage that covers the vegetable.