Leaf veins are important for id in closer species

Now that we have plenty of photographs in efi site, I find that leaf veins play an important role in id not only for general posts, but also for species which otherwise may look similar and confusing.
I generally try to check this aspect when I am not getting sure of the id otherwise.

Also once we narrow down to a genus, it is quite possible to get species id even with only leaves, by matching the leaf veins.

Not just leaf veins but leaf shape, apex, leaf stomata, they all play important role in identification of a plant species. How the tertiary veins end in a vein islet is are also important. But now a days people are in too much of hurry :). People talk about genes without even knowing their plants properly. Some big scientists advocate that we should start giving code names to the plants based on the difference in their DNA because there are not enough scientists in the world to identify plants.

Yes, …

That is true …, French institute Pondicherry used document that data, They will put a white paper over the leaf and do a pencil tracing to record actual vein pattern.

Here is one of my first articles I had worked on 2001 but published in 2003. Not an extraordinary article but gives an idea about how flair morphology can be used in plant identification.

I had just given my masters exam and was sitting idle for 2 months, so please don’t judge me with this article.

Yes indeed …!

So p foetida has the most stomata. I wonder why?
good use of Idle time … I would say ideal (pun intended) ha ha 

I am thinking about your question, which I didn’t think during that IDLE time 18 years ago for obvious reasons….

Why will a plant need more stomata?
The basic answer should be to breathe more. 
Why this plant has to breathe more?
So that it can take more CO2.
Why a plant need to take more CO2?
So that it can release more water.
Why does this plant have to release more water?
Because the plant has glands all over the body which needs to be active and that can happen only by regular supply of water. Plant is herbaceous and hence during blooming time in summer it needs more water intake.
Was just thinking sitting at my office desk, in not so IDLE time…. 🙂
Dont mind please…

here are some very detailed papers on some families by botanists for current plants.
such as this one:
Leaf venation patterns in the genus Saxifraga
but most that I found very useful as a start was from Paleobiology department at the Smithsonian institution
Title   Manual of Leaf Architecture
its a manual  ISBN   0-9677554-0-9
one can easily download it
I thought I had saved the URL but cant find it in this pdf file
its very useful
I like these as a starting point
and for leaf venation nomenclature
see next note…. continued

Leaf venation continued.
for nomenclature of leaf veins I find the Arctic Paleo group called Arctic Plant fossils page the most useful
and there is a fantastic page for tooth types of leaves
I find this very useful
I found the URL for the Smithsonian Manual
https://personal.ems.psu.edu/~pdw3/1999_MLA.pdf

another one I like is this one.
shows importance of good analysis of leaves.
they look different in diff species
A revision of Spondias L. (Anacardiaceae) in the Neotropics
its a paper from NY BOTANICAL GARDEN RESEARCHERS that I admire a lot 

Even trichomes (often incorrectly written as hair) can be of diagnostic value.
Attaching here a recent paper based on the work of one of my M.Sc. student.
I also endorse the statement by Dr Pankaj that number of morphological taxonomists is reducing which is a serious problem world over. However, efloraofindia is an attempt towards encouraging young minds towards morphological taxonomy, I believe.  
Attachments (1)-  Saxifraga trichomes.pdf- 1 mb.

Thanks. what a coincidence. one of the papers I like is also Saxifraga study.
my question: why is saxifrage studied? is it just coincidence or is it a model of some sort of in Taxonomy and Morphological studies in Botany. My question may sound ignorant because I am not a botanist  by academic studies or by trade

If we closely read FPM Gamble, he describes venation for almost all species; even venation in floral leaves is diverse if we observe closely; and as Rawat ji had pointed out indumentum is one more important character in identification; the sad thing is many of the students are not giving importance to morphology; it is a basic necessity for taxonomy, I wonder without  morphological knowledge how could they study taxonomy, in this digital camera age they prefer to compare the images to learn taxonomy, they thought it is a dead subject. 

Sir, as said by…, leaf veins play vital role in id as in case of Ficus religiosa, Ficus arnotianna, Ficus rhumpii

My two bits ! 

Commonly a plant or tree has by numbers leaf on top flowers second and fruits third ! 
Leaves leave behind a visual impression on sub-conscious, an over-all image which we store but do not care to describe ! 
Even from far, shape, size, gloss, hairs, undulation in wind, thickness, petiole, petiole insertion, color, venation, surface, tip…….
and 
close inspection will reveal intricate venation, types of hairs, glands on lamina, petiole, rachis, hairs on veins …….so many characters ! 
What is important is, we store many of these information subconsciously, based on it we tell one species apart from other ……we notice 
differences without exactly knowing what is different ! 
To me this is an important process !
Right lobe first, left lobe later !!! 

There is a much simpler was to look at this.

Lets say there are two cars, same brand, same model, same colour.
The number is different – easiest way.
When number is same? oh, the seat colour is different.
When seat colour is same? One seat is leather and one seat is false leather.
When both seats are leather?  …….
So basically saying, sometimes, it becomes harder to make out the differences. So we go for details on minor scale. both seats are same but one is shiny leather and other is suede.
For example, we cant make out the difference easily between Tinospora cordifolia and T. sinensis, we say one has hairy petiole other has not.
It may not work for all other species, like Spiranthes sinensis comes in both hairy and glabrous form. So we look for other options like dna, may be stomata, may be structure of these hairs. Sometimes it is helpful, sometimes it is not so we keep exploring more and more options.

a very good way to look at.
also most diagnostic algorithms// are inverted trees work exactly as you described.
thanks for explaining it in regular English