My brother sent me a Christmas card that had a leaf enlarged enough to have cells visible. Reminded me of
botany almost seventy years ago. Leaves have tiny openings
whose size can be changed during the day to facilitate uptake of CO2, and release of O2. I can't remember the
name of them. Can you?

Here's a site with some interesting pictures. Wish they had given a means of freezing them when desired.
http://micro.magnet.fsu.edu/primer/java/scienceopticsu/powersof10/

Dear WW: here's a link with some information you might enjoy
http://www.biologie.uni-hamburg.de/b-online/e04/04a.htm

Hey,WW: I finally found a picture of the structure I was looking for. All I could think of was "ostia". That's the mouth of a river. The word I couldn't remember was "stomata". Here's a URL about it:
http://www.microscopy-uk.org.uk/index.html?http://www.microscopy-uk.org.uk/schools/images/stomata.html

Something is goofed up here I keep erasing and entering it over, and error persists. Try copying and pasting it.

Copy just the line that starts with http:// and has stomata in it. I tried it and it works.

Oh, so sorry I didn't happen in until this morning, wwh. What a lovely present to read about leaf-related topics! Yes, stomata I'm very familiar with and love looking very closely at leaves with a magnifying glass to see as much as I can. Botanical gardens typically have posters with cell structures greatly magnified. Would love to know a mnemonic for the photosynthesis cycle!

I think one of the most interesting leaves in terms of depth of structure is that of the Magnolia grandiflora or the Southern magnolia. Its leaves are terrifically thick, very glossly on one side as though polished in a body shop, and then thickly hairy underneath as though covered with brown felt.

Again, thanks for the information and links!

Would love to know a mnemonic for the photosynthesis cycle!
what's the cycle? I'm sure someone would come up with something...

I remember memorizing the photosynthesis and Krebb cycles while in college. I knew one of them would be on the exam so I drew them over and over, to save paper I drew photo. on one side of the paper and Krebb on the back. I got an odd look from the proff during the exam because it was the Krebb cycle and I couldn't start drawing it until I had mimed reaching out and turning over the imaginary paper that it was mentally printed on.
Apparently I have a visual memory.

wwh:

Go back to the first site you listed. If you don't hit the 'auto' button, you can control the speed at which you look at the photographs simply by pressing 'increase' and 'decrease' as you wish.

The oak was one of the varietes of water oak, by the way. The leaf is rather small compared to some of the more well-known oaks species, such as the black and white oaks. The water oak also comes in a type that has a purely lanceolate leaf, very similar to the willow oak that a lot of people refer to incorrectly as the pin oak because the leaves could be said to look like pins. The pin oak, which doesn't have pin-shaped leaves at all, was so called because part of the wood was used in wooden pins, quite strong, in carpentry and fence building.

That water oak on your site is very exciting to spot because of the small leaves, their leathery texture, and the rather pretty leaf shape, somewhat like a duck's foot.

re:The pin oak, which doesn't have pin-shaped leaves at all, was so called because part of the wood

in NY (and other norther climates) Pin Oaks also have the habit of not dropping their russetted leaves till the spring.. (that is the characterist i was taught to identify them.. i never knew why they were called pin oaks-thanks WW.)white oak and black oaks were 'harder'--it had to do with the size of acorns as i recall.

i basicly only know 'NY' trees--and only barely at that-- but NY does have a rich variety--NYC is the norther 'limit' for many southern species, and the southern limit for many norther trees--so there are many varieties!

Samual Parsons -in the early days (1700's) owned a 'garden center/aborium' in Flushing (Queens county)--which was at that time not part of NYC- he specialized in 'exotics'--but 'hardy' trees. His trees live on... Weeping beeching-a normal 'rare variety of tree' is almost common in Queens-some grow 'wild' as street trees. Central Park is another home to great trees--Osago Orange trees (right at the 81st and CPW West enterance to the part there is a small 'grove' with a dozen or so tree.) --and some of the largest trees(of their species)in all of NY State, can be found growing in NYC(according to some federal agency--it was a front page story in NYTimes about 3 years ago!)

HUGE parts of NYC are nothing but concrete-- but NYC (and NYS ) has a long history of creating park land, and protecting it. (the only native, natural wet land left on Long island north shore is in NYC--all the other ones 'have been improved' into beaches and golf courses.)

and on the south shore, a large part of the great jamaica bay is now a federal park of (of several thousand acres!) --albeit, a large part of park is underwater at high tide--called 'Gateway National Park'--its part of many birds migrations routes-and a bird watcher paradice. the park contains about half of the island that make up the archepeligo that is NYC (about 350 islands, 30 to 40 of which are inhabited, (and a small chunk of the US Mainland--the bronx)

NYS has the largest percentage (and close to the largest acrage) in US preserved as park land--only 'federal park land is bigger--(no other state has as much state designated park land)

the NYS park land is protected by NYS constitution, and it requires a constitutional ammendment to 'free park land'--in 100 years, NYS has 'freed' less than 100 acres(and those acres have resulted in huge political battles!)--