Acer hyrcanum ---> Acer opalus

[campoverde]

Hallo,
auf einer Führung wurde ein Ahorn als Acer hyrcanum vorgestellt, ich habe aber jetzt Zweifel.
1. Roloff/Bärtels sagt: "Acer hyrcanum" bis 2m hoch, das ist doch ein Fehler, oder? Im www werden zT aber auch Größen bis 10 oder bis 16m angegeben. Baum bei Führung war mittelgroß.
2. Blatt: mir scheint das eher Acer opalus gewesen zu sein, auch Knospe sieht so aus. Hat vielleicht jemand ein Bild oder Beschreibung von Knospe von Acer hyrcanum? Dann würde ich dort noch einmal vorbeigehen.
Danke!

PS: Nach meinen Beobachtungen dieses sehr interessanten Forums, setze ich die große Hoffnung in eine englischsprachige Antwort.

[JDL]

It is not possible to tell what kind of Maple you are talking about, without an image of it.

The bud of Acer hyrcanum is much smaller (-5mm) than the one of Acer opalus, in general.

There are some subspecies, and the buds varying in colour and in hairiness, very difficult, since these are so small...

To give you an idea to distinguish Acer hyrcanum from other similar or related taxa see an extract of my key (see BELGIAN DENDROLOGY SOCIETY YEARBOOK2007):

66
a Lamina <9 (11) cm broad and long AND central lobe V-shaped, narrowed towards base. ... 67

b Lamina different (OR average broader or longer OR central lobe not V-shaped). ................. 68

67
a Mature lamina conspicuously ciliate at margin and abaxially densely hairy even on the smallest veinlets (SEE 69a). A. saccharum susbsp. grandidentatum

b Mature lamina not ciliate at margin, abaxially glabrous to variable but not densely hairy. .................... A. hyrcanum (Acer/Monspessulana)

- Shrub, leaf 3-lobed and 0,5-1,5 cm across. Leaf margin wavy and with sharp, fine +/- prickling teeth. ....... A. hyrcanum subsp. reginae-amaliae

- Tree or shrub, leaf 3- to 5-lobed, 3-10 cm across. Leaf margin flat, never so finely toothed.

o Leaf 3-lobed (at most with very small basal lobes, samara’s <1 cm)...... A. hyrcanum subsp. sphaerocarpum
o Leaf 5- lobed (samara’s 3-4 cm).

Leaf margin with lobulate to rounded teeth or +/- crenate.
- Lamina dull, thin. Central lobe with <4 rounded teeth. ..... A. hyrcanum subsp. keckianum
- Lamina smooth, thick. Central lobe with >5 rounded teeth. A. hyrcanum var. granatense

Leaf margin with blunt to +/- sharp teeth.

- Lamina abaxially blue-green. .............. A. hyrcanum subsp. intermedium
- Lamina abaxially green.

- Lobes pointed at apex and toothed. ..... A. hyrcanum subsp. tauricolum
- Lobes blunt at apex and bluntly toothed. .............. A. hyrcanum subsp. hyrcanum

excuse me but the layout is not what I would like to show

[campoverde]

Thank you, your info re size of the bud should be helpful. I will doublecheck.
Can you confirm that statement that A.h. is only up to 2m high is incorrect?

[JDL]

multibranched shrub (2m) to broadly domed tree up to 17 meter

[campoverde]

Hallo,
ich habe jetzt doch noch ein Blatt gefunden, das ich im Sommer gepresst habe und das gut zu Acer opalus passt.
Die Knospen würden auch gut passen und laut Jans Info nicht zu Acer h., somit denke ich, daß das Acer opalus ist und die Info bei der Führung nicht korrekt. Stimmt Ihr mir zu?

[JDL]

I should also go for Acer opalus

[campoverde]

The bud of Acer hyrcanum is much smaller (-5mm) than the one of Acer opalus, in general.

Hello Jan,
I would like to ask two additional questions
1. In case of Acer hyrcanum also terminal bud typically <=5mm? Terminal Buds in my pictures roughly 1cm.
2. According to R/B there is one more easy criterion:
A. hyrcanum "Milchsaft"
A. opalus "kein Milchsaft"
Can you confirm this criterion?
(And is it correct to say "lactiferous" for showing "Michsaft"?)

(Background of my questions: I had been very convinced of Acer opalus, but now I was questioned once again, therefore I doublecheck)
Thank you!

[JDL]

Campoverde,

The bud:
generally the bud is smaller (I talk about the end bud, always)

The sap:

lactiferous is a good word (when the sap is white)

hyaline is a word when the sap is transparent

as far as I know Acer hyrcanum does NOT show milky sap when the petiole is cut through. It does not belong to the section Platanoidea, but the section Acer.

other distinguishing character:

the terminal lobe is narrowing at its base for Acer hyrcanum

the terminal lobe is broadening at its base for Acer opalus LIKE YOUR IMAGE

grtjs

Jan

[campoverde]

Danke!