Acer acuminatum Wall. ex D.Don (India (Himachal Pradesh, Uttar Pradesh), Jammu & Kashmir (Kashmir) as per Catalogue of Life)

/wp-content/uploads/2020/10/Acer%20species%20I%20IMG_4068.jpg
/wp-content/uploads/2020/10/Acer%20species%20I%20IMG_4066.jpg
/wp-content/uploads/2020/10/Acer%20species%20I3%20IMG_4066.jpg
/wp-content/uploads/2020/10/Acer%20species%20I4%20IMG_4066.jpg
/wp-content/uploads/2020/10/Acer%20sp.%201%20-6-.JPG
/wp-content/uploads/2020/10/Acer%20sp.%201%20-7-.JPG
/wp-content/uploads/2020/10/Acer%20sp.%201%20-8-.JPG
/wp-content/uploads/2020/10/Acer%20sp.%201%20-1-.JPG
/wp-content/uploads/2020/10/Acer%20sp.%201%20-2-.JPG
/wp-content/uploads/2020/10/Acer%20sp.%201%20-3-.JPG
/wp-content/uploads/2020/10/Acer%20sp.%201%20-4-.JPG
/wp-content/uploads/2020/10/Acer%20sp.%201%20-5-.JPG

Acer caesium Wall. ex Brandis (E. Afghanistan to N. & E. Central China as per POWO; India (Uttar Pradesh, Himachal Pradesh, Tamil Nadu (c)), Jammu & Kashmir (Poonch, Kashmir), Pakistani Kashmir (Azad Kashmir), Bangladesh, Afghanistan (Kunar / Nuristan), Pakistan (Dir, Chitral, Swat, Hazara, Murree), Tibet as per Catalogue of Life)

 /wp-content/uploads/2020/10/Acer%20sp.%203.JPG
/wp-content/uploads/2020/10/Acer%20caesium%20Vof%20-2-.JPG
/wp-content/uploads/2020/10/Acer%20caesium%20-1-.JPG
/wp-content/uploads/2020/10/Acer%20caesium%20-2-.JPG
/wp-content/uploads/2020/10/Acer%20caesium%20-3-.JPG
 /wp-content/uploads/2020/10/Acer%20caesium.jpg
/wp-content/uploads/2020/10/IMG_1070.JPG
/wp-content/uploads/2020/10/IMG_1068.JPG
/wp-content/uploads/2020/10/AcerIMG_0404.JPG
/wp-content/uploads/2020/10/AcerIMG_0403.JPG

Acer cappadocicum var. indicum (Pax) Rehder (Pakistan (Swat, Chitral, Hazara, Murree), Jammu & Kashmir (Poonch, Kashmir), Bhutan, Sikkim, N-India (Assam, Himachal Pradesh, Uttar Pradesh, West Bengal, Arunachal Pradesh, Meghalaya, Manipur, Mizoram), Nepal, S-Tibet, China (NW-Yunnan) as per Catalogue of Life)
/wp-content/uploads/2020/10/Acer%20cappadocicum%20-1-.JPG/wp-content/uploads/2020/10/Acer%20cappadocicum%20-3-.JPG/wp-content/uploads/2020/10/Acer%20cappadocicum%20-4-.JPG/wp-content/uploads/2020/10/Acer%20cappadocicum%20-2-.JPG/wp-content/uploads/2020/10/Acer%20cappadocicum%20-5-.JPG/wp-content/uploads/2020/10/Acer%20cappadocicum%20-6-.JPG
/wp-content/uploads/2020/10/Acer%20sp.%202%20-2-.JPG
/wp-content/uploads/2020/10/Acer%20sp.%202%20-4-.JPG
/wp-content/uploads/2020/10/Acer%20sp.%202%20-6-.JPG
/wp-content/uploads/2020/10/Acer%20sp.%202%20-1-.JPG
/wp-content/uploads/2020/10/Acer%20sp.%202%20-3-.JPG
/wp-content/uploads/2020/10/Acer%20sp.%202%20-5-.JPG
/wp-content/uploads/2020/10/Acer%20sp.%202%20-7-.JPG

/wp-content/uploads/2020/10/Acer%20lobelii%20-3-.JPG/wp-content/uploads/2020/10/Acer%20lobelii%20-2-.JPG/wp-content/uploads/2020/10/Acer%20lobelii%20-1-.JPG/wp-content/uploads/2020/10/Acer%20lobelli%20-2-.JPG/wp-content/uploads/2020/10/Acer%20lobelli%20-1-.JPG/wp-content/uploads/2020/10/Acer%20lobelli%20-3-.JPG


Acer caudatum Wall. (Himalaya to N. & E. Central China and N. Myanmar: Assam, China North-Central, China South-Central, China Southeast, East Himalaya, Inner Mongolia, Myanmar, Nepal, Tibet, West Himalaya as per POWO)

  


Acer negundo L. (Introduced in India)
(Native to: Alabama, Arizona, Guatemala, Illinois, Kentucky, Mexico Central, Mexico Gulf, Mexico Northeast, Mexico Northwest, Mexico Southeast, Mexico Southwest, Missouri, New York, Tennessee, Vermont; Introduced into: Albania, Algeria, Altay, Argentina Northeast, Austria, Belarus, Belgium, Bolivia, Bulgaria, Buryatiya, Central European Rus, China North-Central, China South-Central, China Southeast, Czechoslovakia, EastEuropean Russia, France, Germany, Greece, Hungary, Iraq, Italy, Kazakhstan, Khabarovsk, Korea, Morocco, New Zealand South, Primorye, Sakhalin, Spain, Sweden, Tadzhikistan, Turkey, Turkey-in-Europe, Turkmenistan, Ukraine, Uzbekistan, Vietnam, West Himalaya, West Siberia, Yukon as per POWO)

/wp-content/uploads/2020/10/Acer-negundo-Kashmir-b.jpg

/wp-content/uploads/2020/10/Acer-negundo-Kashmir-a.jpg

/wp-content/uploads/2020/10/P1390222.JPG
/wp-content/uploads/2020/10/P1390223.JPG
/wp-content/uploads/2020/10/P1390226.JPG
/wp-content/uploads/2020/10/P1280469.JPG
/wp-content/uploads/2020/10/P1280474.JPG
/wp-content/uploads/2020/10/P1280470.JPG

 

/wp-content/uploads/2020/10/P1280471.JPG
/wp-content/uploads/2020/10/P1280473.JPG
 /wp-content/uploads/2020/10/P1290791.JPG/wp-content/uploads/2020/10/P1290790-7.JPG/wp-content/uploads/2020/10/P1290792.JPG/wp-content/uploads/2020/10/P1290789.JPG

Acer oblongum Wall. ex DC. (Himalaya to Central & S. China and Indo-China as per POWO; India (Darjeeling, Assam, Himachal Pradesh, Uttar Pradesh, Arunachal Pradesh, Meghalaya, Manipur, Nagaland), Bhutan, Sikkim, Jammu & Kashmir (Poonch, Kashmir), Pakistan (Rawalpindi), Pakistani Kashmir (Mirpur), Nepal, China (Fujian, S-Gansu, Guizhou, W-Hubei, S-Shanxi, Sichuan), Taiwan, S-Tibet, Myanmar [Burma] (Chin, Mandalay, Sagaing, Shan), Vietnam as per Catalogue of Life)
/wp-content/uploads/2020/10/Acer%20fruit.jpg/wp-content/uploads/2020/10/Acer%20inflorescence.jpg/wp-content/uploads/2020/10/Acer%20flower.jpg/wp-content/uploads/2020/10/Acer%20fruit%201.jpg/wp-content/uploads/2020/10/Acer%20leaves.jpg/wp-content/uploads/2020/10/Acer%20seeds.jpg

 

 

 /wp-content/uploads/2020/10/Acer%20-9-.jpg/wp-content/uploads/2020/10/Acer%20-2-.jpg/wp-content/uploads/2020/10/Acer%20-7-.jpg/wp-content/uploads/2020/10/Acer%20-8-.jpg
/wp-content/uploads/2020/10/Acer%20sp.%20-6-.JPG
/wp-content/uploads/2020/10/Acer%20sp.%20-1-.JPG
/wp-content/uploads/2020/10/Acer%20sp.%20-2-.JPG
/wp-content/uploads/2020/10/Acer%20sp.%20-3-.JPG
/wp-content/uploads/2020/10/Acer%20sp.%20-4-.JPG
/wp-content/uploads/2020/10/Acer%20sp.%20-5-.JPG
/wp-content/uploads/2020/10/_DSC0400.JPG/wp-content/uploads/2020/10/_DSC0479.JPG/wp-content/uploads/2020/10/_DSC0396-4.JPG/wp-content/uploads/2020/10/_DSC0391.JPG/wp-content/uploads/2020/10/_DSC0398.JPG

Acer palmatum Thunb. (Introduced in India)
(Japan, Taiwan, South Korea, China (Anhui, Fujian, Guizhou, ?Hebei, S-Henan, Hubei, Hunan, Jiangsu, Jiangxi, ?Liaoning, Shandong, ?Sichuan, Zhejiang), Germany (I), USA (I) (District of Columbia (I), Delaware (I), New York (I), Ohio (I), Pennsylvania (I)), Canada (I) (Ontario (I)), Slovakia (I), Croatia (I) as per Catalogue of Life)

 /wp-content/uploads/2020/10/Srinagar-IMG_2960.JPG/wp-content/uploads/2020/10/Srinagar-IMG_2959.JPG
/wp-content/uploads/2020/10/Acer-palmatum-Univ-campus-DSC06235-Kashmir-2.jpg
/wp-content/uploads/2020/10/Acer-palmatum-DSC04939-SFOBG-California-2.jpg
/wp-content/uploads/2020/10/Acer-palmatum-Univ-campus-DSC06236-Kashmir-3.jpg

/wp-content/uploads/2020/10/Acer-palmatum-Univ-campus-DSC06233-Kashmir-1.jpg

/wp-content/uploads/2020/10/Acer-palmatum-Univ-campus-DSC06233-Kashmir-1-9.jpg
/wp-content/uploads/2020/10/Acer%20japonicum1.jpg
/wp-content/uploads/2020/10/IMG_9197-ph.jpg
/wp-content/uploads/2020/10/IMG_9191-ph.jpg
/wp-content/uploads/2020/10/IMG_9193-ph.jpg
/wp-content/uploads/2020/10/IMG_9194-ph.jpg
/wp-content/uploads/2020/10/IMG_9189-ph.jpg

/wp-content/uploads/2020/10/Acer-palmatum-DSC04940-SFOBG-California-3.jpg/wp-content/uploads/2020/10/Acer-palmatum-DSC04941-SFOBG-California-1.jpg

/wp-content/uploads/2020/10/P1310261.JPG

/wp-content/uploads/2020/10/P1310260.JPG

/wp-content/uploads/2020/10/P1270655.JPG
/wp-content/uploads/2020/10/P1280040.JPG
/wp-content/uploads/2020/10/P1270657.JPG
/wp-content/uploads/2020/10/P1270656.JPG
/wp-content/uploads/2020/10/P1280591.JPG
/wp-content/uploads/2020/10/P1280555.JPG
/wp-content/uploads/2020/10/P1280554.JPG
/wp-content/uploads/2020/10/P1280553.JPG
/wp-content/uploads/2020/10/P1280607.JPG/wp-content/uploads/2020/10/P1280682.JPG/wp-content/uploads/2020/10/P1280667.JPG/wp-content/uploads/2020/10/P1280606.JPG/wp-content/uploads/2020/10/P1280566.JPG/wp-content/uploads/2020/10/P1280564.JPG/wp-content/uploads/2020/10/P1280604.JPG/wp-content/uploads/2020/10/P1280565.JPG/wp-content/uploads/2020/10/P1280567.JPG

Acer pectinatum Wall. ex Brandis (Himalaya to China (NW. Yunnan) and NE. Myanmar: Assam, China South-Central, East Himalaya, Myanmar, Nepal, Tibet, West Himalaya as per POWO)

 


Acer pseudoplatanus L. (Introduced in India) (Austria, Belgium, Czech Republic, Slovakia, Germany, Switzerland, Netherlands, Hungary, Poland, Romania, England (I), Denmark (I), Ireland (I), Sweden (I), Portugal, Spain, France, Corsica, Sicily, Italy, Slovenia, Croatia, Bosnia & Hercegovina, Montenegro, Serbia & Kosovo, Macedonia, Albania, Bulgaria, Greece, European Turkey, Belarus (I), Estonia (I), Lithuania (I), Latvia (I), C-European Russia, Ukraine, Northern Caucasus, Georgia [Caucasus], Kazakhstan (I), Uzbekistan (I), Australia (I) (Victoria (I), Tasmania (I)), New Zealand (I), Chatham Isl. (I), Azores (I) (Sao Miguel Isl. (I)), Madeira (I) (Madeira Isl. (I)), Canary Isl. (I) (Gran Canaria (I)), Algeria (I), USA (I) (Connecticut (I), District of Columbia (I), Delaware (I), Illinois (I), Kentucky (I), Massachusetts (I), Maryland (I), Maine (I), Michigan (I), North Carolina (I), New Jersey (I), New York (I), Pennsylvania (I), Rhode Island (I)), Canada (I) (British Columbia (I), New Brunswick (I), Nova Scotia (I), Ontario (I)) as per Catalogue of Life)
/wp-content/uploads/2020/10/Type36_Bratislava_IMG_9176.JPG/wp-content/uploads/2020/10/Type36_Bratislava_IMG_9178.JPG/wp-content/uploads/2020/10/Type36_Bratislava_IMG_9179.JPG/wp-content/uploads/2020/10/Type36_Bratislava_IMG_9175.JPG/wp-content/uploads/2020/10/Type36_Bratislava_IMG_9173.JPG/wp-content/uploads/2020/10/Type36_Bratislava_IMG_9177.JPG

Acer saccharum Marshall (Introduced in India) (USA (Alabama, Arkansas, Connecticut, Delaware, Georgia, Iowa, Illinois, Indiana, Kansas, Kentucky, Louisiana, Massachusetts, Maryland, Maine, Michigan, Minnesota, Missouri, Mississippi, North Carolina, North Dakota, New Hampshire, New Jersey, New York, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Dakota, Tennessee, Virginia, Vermont, Wisconsin, West Virginia), Canada (New Brunswick, Nova Scotia, Ontario, Prince Edward Isl., Quebec), European Russia (introduced), Korea (introduced) as per Catalogue of Life)

/wp-content/uploads/2020/10/P1190737.JPG

Acer sterculiaceum Wall. (Himalaya to China (NW. Yunnan) as per POWO; India (Darjeeling, Kumaon, Assam, Himachal Pradesh, Uttar Pradesh, West Bengal, Arunachal Pradesh, Manipur), Bhutan, Sikkim, Jammu & Kashmir, China (NW-Yunnan), S-Tibet, Myanmar [Burma] (Kachin) as per Catalogue of Life)
/wp-content/uploads/2020/10/Acer-cappadocicum-confirm-Chopta%20Mandal%20Road-IMG_2991-Uttarakhand-4.jpg
/wp-content/uploads/2020/10/Acer-cappadocicum-confirm-Chopta%20Mandal%20Road-IMG_2995-Uttarakhand-3.jpg
/wp-content/uploads/2020/10/Acer-cappadocicum-confirm-Chopta%20Mandal%20Road-IMG_2996-Uttarakhand-5.jpg
/wp-content/uploads/2020/10/Acer-cappadocicum-confirm-Chopta%20Mandal%20Road-IMG_2994-Uttarakhand-2.jpg
 /wp-content/uploads/2020/10/Acer%20sp%20-2-.JPG/wp-content/uploads/2020/10/Acer%20lobelii%20subsp.%20pictum%20ckt%20-2-.JPG/wp-content/uploads/2020/10/Acer%20lobelii%20subsp.%20pictum%20ckt%20-6-.JPG/wp-content/uploads/2020/10/Acer%20sp%20-1-.JPG
/wp-content/uploads/2020/10/Acer-sp-Chopta%20forest-IMG_2228-Uttarakhand-2.jpg
/wp-content/uploads/2020/10/Acer-sp-Chopta%20forest-IMG_2209-Uttarakhand-3.jpg
/wp-content/uploads/2020/10/Acer-sp-Chopta%20Mandal%20Road-IMG_2992-Uttarkhand-1.jpg

.

Keys in Flora of Pakistan


.

/wp-content/uploads/2020/10/Acer-2.JPG

Keys as per BSI Flora of India (Vol. 5) by M P Nayyar and Anukul Dutta


.

Keys in Flora of Nepal Online account (by Vidya Manandhar and Colin A. Pendry in 2018):

1a Leaves unlobed (sometimes slightly 3-lobed in A. stachyophyllum and A. thomsonii) …..2.
b Leaves 3- to 7(–9)-lobed …..6.
2a Leaves unlobed or slightly 3-lobed, inflorescence racemose ……3.
b Leaves always unlobed, inflorescence paniculate or racemose ……4.
3a Leaf margin serrate, inflorescence glabrous, flowers 4-merous ….8. A. stachyophyllum
b Leaf margin sub-entire or repand, inflorescence villous, flowers 5-merous …..11. A. thomsonii
4a Leaves ovate, inflorescence racemose ……5. A. sikkimense
b Leaves oblong ovate, inflorescence broadly paniculate……..5.
5a Leaf margin sub-entire, often serrulate near apex, inflorescence glabrous ….. 3. A. laevigatum
b Leaf margin entire, inflorescence pubescent ……4. A. oblongum
6a Leaves 7-lobed, inflorescence paniculate or corymbose, glabrous …….7.
b Leaves 3–5-lobed, inflorescence racemose, paniculate, or corymbose, glabrous or pubescent ……8.
7a Leaf margin entire, inflorescence corymbose ……..1. A. cappadocicum
b Leaf margin serrate or serrulate, inflorescence paniculate ……2. A. campbellii
8a Inflorescence broadly paniculate ……..9.
b Inflorescence racemose ………10.
9a Leaves mostly 3-lobed, margin double serrate, serration acute, flowers 4-merous …..7. A. acuminatum
b Leaves 5-lobed, margin serrate, serration obtuse, flowers 5-merous …….9. A. caesium
10a Leaf margin entire or repand, inflorescence villous …..11. A. thomsonii
b Leaf margin serrate, inflorescence glabrous, pubescent, or villous ……11.
11a Inflorescence pubescent or villous  ……..12.
b Inflorescence glabrous …….13.
12a Leaf margin double serrate, inflorescence paniculate raceme, pubescent, samara glabrous, wings diverging at a 40– 55 deg. angle ……. 10. A. caudatum
b Leaf margin distantly serrate, inflorescence simple raceme, villous, samara villous, wings diverging at a 10–25 deg. angle …… 12. A. sterculiaceum
13a Leaf margin setosely serrate, flowers 5-merous, samara wings diverging at a 80–90o angle ….6. A. pectinatum
b Leaf margin serrate or double serrate, flowers 4-merous, samara wings diverging at a 20–55 deg. angle ….8. A. stachyophyllum


.

Keys in Flora of Bhutan by AJC Grierson and D G Long, Vol.2 Part 1 (1993):
1. Leaves narrowly oblong-elliptic, always unlobed; base narrowly rounded … 2
+ Leaves ovate to suborbicular, often 3 — 7-lobed, sometimes unlobed; base truncate or broadly rounded or shallowly to deeply cordate .. .. 3
2. Leaves quite entire, usually glaucous and glabrous beneath; petiole 2 — 6cm 1. A. oblongum
+ Leaves often serrulate near apex, green and reticulate beneath and sometimes pubescent in vein axils; petiole 1 – l.5cm … .. 2. A. laevigatum
3. Leaves unlobed or all 3-lobed, with usually shallow lobes ….. .. 4
+ Leaves 3 — 7-lobed, usually deeply so, never unlobed (if 3-lobed then often with 2 additional very small lobes near base) …….. 9
4. Leaves unlobed (rarely with 2 very small lateral lobes in A. hookeri) ……. .. 5
+ Leaves with 2 distinct lateral lobes … .. 7             

5. Flowers in short, lax often +/- cymose racemes; leaves coarsely and unequally serrate, softly pubescent beneath or with conspicuous tufts of hair in vein axils beneath 5. A. stachyophyllum
+ Flowers in long slender spike-like racemes; leaves entire, senulate or more regularly serrate, glabrous beneath or with inconspicuous tufts of hair in vein axils … .. 6
6. Leaves sharply serrate; bud scales not persistent at flowering time 3. A. hookeri (syn. of
Acer sikkimense subsp. sikkimense)
+ Leaves entire or obscurely semilate; bud scales often persistent at flowering time …… 4. A. sikkimense
7. Leaves not strongly reticulate, margins doubly serrate …….. 6. A. taronense syn. of Acer pectinatum subsp. taronense (Hand.-Mazz.) E. Murray
+ Leaves +/- strongly reticulate, margins entire to serrulate ……….. .. 8
8. Leaves elliptic to obovate, 8 — 15 x 4 — 13cm, with a tuft of long pale hairs at petiole insertion on upper surface when young, margins serrulate; mericarps diverging at right angles 7. A. osmastonii (syn. of
Acer calcaratum Gagnep. as per POWO)
+ Leaves broadly ovate or suborbicular, 10 – 23 x 7 – 20cm, finely and shortly puberulous at base on upper surface when young, margins entire or obscurely serrate; mericarps ascending, sometimes almost parallel …. .. 8. A. thomsonii
9. Leaf margin quite entire .. .. 9. A. cappadocicum (Only Acer cappadocicum var. indicum (Pax) Rehder has distribution as per Catalogue of Life😉
+ Leaf margin serrate or serrulate, sometimes doubly so … .. 10
10. Leaf margin coarsely doubly serrate ….. .. 11. A. caudatum
+ Leaf margin finely serrulate or distantly but regularly serrate (rarely weakly doubly serrate in A. pectinatum) … .. 11
11. Mature leaves glabrous beneath, or with a few pale hairs in vein axils beneath, 5 – 7-lobed … .. 10. A. campbellii
+ Mature leaves usually pubescent beneath at least along veins, 3 – 5-lobed …. 12
I2. Branchlets slender; leaf margin closely serrate; pubescence reddish 12. A. pectinatum
+ Branchlets stout; leaf margin distantly serrate; pubescence whitish 13. A. sterculiaceum


.
Acer : 2 posts by 2 authors.

I have updated eFI (efloraofindia) page on Acer

Attempts have been made to incorporate most of the species available in India & nearby areas with details & keys directly or through links as far as possible. It’s quite possible that there may be some discrepancy in the accepted names & synonyms taken from other databases/ books.

Species discussed so far in efloraofindia are given at the bottom of the page in the form of links against Subpages. On clicking them one can see all the details.

Any comments are welcome.


.

Providing a piece of information on Acer in India. If useful it may be added on page on Acer

Two important documents of Acer species of India are:
1. Nayar,M.P. & Dutta, A. (1982). Fascicles of Flora of India, Fascicle 9, Aceraceae. BSI Howrah,P22.
2. Nayar,M.P. & Dutta, A. (2000). Aceraceae. In: Singh, N.P., Vohra, J.N., Hajra, P.K. and Singh, D.K. (eds.) Flora of India Vol-5. BSI Calcutta, pp. 392-410. 
As per the above information following species of Acer are known from India:
1. Acer acuminatum
2. Acer caesium (diagram in ref-1,2) [Status in Red Data Book of Indian Plants Vol-I (Nayar & Sastry, 1987)- Vulnerable]
3. Acer campbellii var. campbellii and A.campbellii var. serratifolium
4. Acer cappadocicum (diagram in ref-1,2)- Only Acer cappadocicum var. indicum (Pax) Rehder has distribution as per Catalogue of Life;
5. Acer caudatum
6. Acer hookeri var. hookeri (syn. of Acer sikkimense subsp. sikkimense) and A.hookeri var. majus. [Status in Red Data Book of Indian Plants Vol-I (Nayar & Sastry, 1987)- Endangered, diagram provided]
7. Acer laevigatum
8. Acer laurinum
9. Acer oblongum var. membranaceum. [Status in Red Data Book of Indian Plants Vol-I (Nayar & Sastry, 1987)- Endangered, diagram provided] A.oblongum var. microcarpum. [Status in Red Data Book of Indian Plants Vol-I (Nayar & Sastry, 1987)- Endangered,diagram provided] and A.oblongum var. oblongum (diagram in ref-1,2)
10. Acer x osmastonii [Status in Red Data Book of Indian Plants Vol-I (Nayar & Sastry, 1987)- Endangered, diagram provided]- syn. of Acer calcaratum Gagnep. as per POWO;
11. Acer pectinatum
12. Acer pentapomicum
13. Acer pinnatinervium
14. Acer sikkimense var. sikkimense and A.sikkimense var. serrulatum. [Status in Red Data Book of Indian Plants Vol-I (Nayar & Sastry, 1987)- Endangered, diagram provided]
15. Acer stachyophyllum
16. Acer sterculiaceum
17. Acer thomsonii (diagram in ref-1,2) 
In these two documents keys for identification of species, description of species, distribution, flowering and fruiting periods and chromosome numbers are provided. 
Ref- 1 has also given diagrams of samaras (fruits) of all species except (A.pinnatinervium). 
 
In addition to above species, following are also known in India:

18. Acer forrestii Diels
19. Acer pseudoplatanus L. (Cultivated)
20. Acer saccharum Marshall (Cultivated)
21. Acer x schwerinii Pax
22. Acer wardii W.W.Sm.

Reference
Karthikeyan, S., Sanjappa, M. and Moorthi, S. 2009. Flowering plants of India Dicotyledons volume 1 (Acanthaceae-Avicenniaceae). BSI, Kolkata. pp. 62-64.


.

Flora of Peninsular India with keys at species links, if any:
Acer caesium Wall. ex Brandis (Planted in Hill stations)

Acer laurinum Hassk. (A.P.- Vishakhapatnam district)
Acer negundo L. (Cultivated- Victoria Gardens, Maharashtra)
Acer oblongum Wall. ex DC. (Planted in Hill stations- Tamilnadu- Nilgiri district)
Acer pseudoplatanus L. (Planted in Hill stations)

.

Species with description & keys in Flora of Pakistan (Distribution):
Acer acuminatum Wall. ex D. Don (Kashmir to Nepal from 2200 to 3500 m altitude)
Acer caesium Wall. ex Brandis (Hindukush and Himalayas)
Acer campestre Linn. (Europe, NW. Africa, Caucasia, N. Iran and Pakistan)
Acer cappadocicum Gleditsch (N.E. Turkey, Caucasus, N. Iran, Himalayas to China and Japan)
Acer negundo Linn. (This North American species is cultivated in Bagh-i-Jinnah, Lahore and according to Parker, l.c., “It does well in the plains.”)
Acer oblongum Wall. ex DC. (Pakistan and India to South China- It grows in the lower Himalayan foothills from 600 to 2000 m elevation in moist forests, especially along streams)
Acer pentapomicum J.L. Stewart ex Brandis (Turkestan, Hindukush, Afghanistan, NW. Himalaya in India and Pakistan)
Acer turkestanicum Pax (N.E. Afghanistan, Turkestan, Pamir Alai, Tien Shan and Pakistan)

.

Species with distribution in annotated checklist of Flowering plants of Nepal (Distribution):

Acer acuminatum (2200-3200 m; Himalaya (Kashmir to Nepal))

Acer caesium (2200-3000 m; Himalaya (Kashmir to Nepal))

Acer campbellii (2100-3600 m; Himalaya (Nepal to NEFA), Burma)

Acer cappadocicum

Acer cappadocicum var. indicum (2100-3000 m; C. Asia, Himalaya (Kashmir to Bhutan), Assam)
Acer caudatum (3000-4000 m; Himalaya (Kumaun to Bhutan), S. Tibet, ?Burma)
Acer hookeri (2300 m; E. Himalaya (Nepal to NEFA)) syn. of Acer sikkimense Miq. 
Acer laevigatum (1200-1800 m; Himalaya (Garhwal to Sikkim), Assam, N. Burma, W. & C. China)
Acer oblongum (120-2400 m; Himalaya (Kashmir to Bhutan), Assam, Burma, Indo-China, W. & C. China)
Acer pectinatum (2700-3800 m; Himalaya (Nepal to Bhutan), S. Tibet, N. Burma)
Acer sikkimense (1800-2100 m; E. Himalaya (Nepal to Bhutan), Assam. S. Tibet, N. Burma, W. China)
Acer stachyophyllum (2700-3000 m; E. Himalaya (Nepal to Bhutan), S. Tibet)
Acer sterculiaceum (2200-3200 m; Himalaya (Kashmir to Bhutan), Assam)
Acer sterculiaceum var. tomentosum
Acer thomsonii (1300-1400 m; E. Himalaya (Nepal to Bhutan), Assam, N. Burma)

Acer acuminatum Wallich ex D. Don [N India, Kashmir, Nepal, Pakistan].
Acer caesium Wallich ex Brandis [N India, Nepal, Pakistan].
Acer calcaratum Gagnepain  [Myanmar, Thailand, Vietnam].
Acer campbellii J. D. Hooker & Thomson ex Hiern in J. D. Hooker [Bhutan, N India, Myanmar, Nepal, Vietnam].
Acer cappadocicum subsp. cappadocicum [Bhutan, N India (Assam, Sikkim), Kashmir, Nepal, Pakistan; SW Asia (Caucasus, Iran, Turkey), S Europe (S Italy)].
Acer caudatum Wallich [Bhutan, N India, Myanmar, Nepal].
Acer forrestii Diels (SW Sichuan, NW Yunnan)
Acer laevigatum Wallich  [Bhutan, N India, Myanmar, Nepal, Vietnam].
Acer laurinum Hasskarl [Cambodia, S India, Indonesia, Laos, Malaysia, Myanmar, Philippines, Thailand, Vietnam]
Acer negundo Linnaeus [Widely cultivated and naturalized in China [native to North America]]
Acer oblongum Wallich ex Candolle [Bhutan, N India, S Japan, Kashmir, Laos, Myanmar, Nepal, Pakistan, Thailand, Vietnam].
Acer palmatum Thunberg (Widely cultivated in gardens in China [native to Japan and S Korea])
Acer pectinatum Wallich ex G. Nicholson [Bhutan, NE India, NE Myanmar, Nepal].
Acer pinnatinervium Merrill [N India, Thailand].
Acer sikkimense Miquel [Bhutan, N India, N Myanmar, Nepal].
Acer stachyophyllum Hiern in J. D. Hooker [Bhutan, N India, Myanmar, Nepal].
Acer sterculiaceum Wallich [Bhutan, N India].
Acer thomsonii Miquel [Bhutan, N India, Myanmar, Nepal, Thailand].
Acer wardii W. W. Smith [NE India, NE Myanmar].
Binomial Habit Notes Ref. Distrib.
Acer
caesium
Wall. ex Brandis
Tree Western Ghats,
High Altitude, Cultivated, Native of Himalaya
Flora of Tamil
Nadu, VOL. I, 1983
Dindigul,
Nilgiri
Acer oblongum Wall. ex DC.  Tree Western
Ghats, High Altitude, Cultivated, Native of Indio China
Flora
of Tamil Nadu, VOL. I, 1983
Dindigul,
Nilgiri
Acer pseudoplatanus L. Tree Western
Ghats, High Altitude, Cultivated, Native of Eurasia
Flora
of Tamil Nadu, VOL. I, 1983
Dindigul

.
Species with description & pictures in Flowers of India as on 11.1.14:  

Botanical name Synonyms Family Common name
Acer acuminatum Acer caudatum Aceraceae Tapering Leaf Maple
Acer caesium Acer molle Aceraceae Bluish Grey Maple
Acer cappadocicum Acer divergens, Acer laetum Aceraceae Caucasian Maple
Acer negundo Aceraceae Three-Leaved Maple
Acer oblongum Aceraceae Himalayan Maple

. 

Forest Plants of Eastern India By Amal Bhusan Chaudhuri (1993- p. 183)- Brief details with Keys-
Acer osmastonii Gamble is a syn. of Acer calcaratum Gagnep.

Cold Deserts of India By S.S. Negi (2002)

1997 IUCN Red List of Threatened Plants edited by Kerry Scott Walter, Harriet J. Gillett
Acer caesium– V- Himachal, J & K, Uttar Pradesh
Acer molle Pax synonym of Acer caesium– I- Western Himalayas

.

Pl. go through Acer‎‎ (Sapindaceae) page with comparative images of species in efloraofindia. On clicking the link of species, one can check the complete details. Genus pages generally give details of most of the species found in India.
I request you to pl. go through & point out mistakes, if any. I hope this will aid in identifications in future. If anybody can send images of other species of this genus (for incorporation in the website), if any, or can identify unidentified images, it will be really nice.