Detailed Descriptions

HABIT AND TRUNK:

Large tall deciduous tree reaching heights of 105ft (50m) or more on maturity, with a wide domed crown. The bark is smoothish, beech-like, grey to grey-green with lighter slightly roughened patches here and there.

Acer velutinum: trunk of a 50 years old specimen at Kew Gardens (photo: Hugh Angus)

 

 

Winter shoot with characteristic brown buds (photo: Hugh Angus).

Branches are rather stout, dark grey to grey-brown. The stout current shoots are green to mid-brown, glabrous and semi-glossy with small scattered light orange-brown longitudinal lenticels. The shoots become reddish-brown in  the  autumn, changing to light-brown to grey-brown in the second and subsequent years. The leaf scars

SHOOTS AND BUDS:

are a lighter grey-brown, almost V-shaped, more than twice as wide as deep with a fringe of hairs on the upper side at the bud bases, the pairs of scales

not quite encircling the shoot,

 

 

but are connected by a horizontal ridge on each side. The shoot bases are encircled by a conspicuous 5mm wide girdle of numerous bud-scale rings.

The medium-sized oval dark brown winter buds - 10- 15mm long and 5-7mm wide - have lighter brown pointed tips and numerous overlapping bud scales. There are 5-6 pairs of broad oval outer scales with short grey-brown hairs on the outer surface, towards the pointed tips. The 4-5 pairs of inner scales are narrower, light yellow-green and with short silky white hairs on the outer surface.

LEAVES:

The large sycamore-like palmate, 5-lobed leaves are slightly undulated, usually as broad or broader than long - up to 15cm long and 17cm wide, occasionally larger - with slightly heart-shaped to truncate bases. The lobes are ovate to obovate with short acuminate tips, and with the lower sides of the central lobe parallel or angled slightly inwards. The pair of basal lobes are distinct but much smaller. The junction between adjacent lobes (sinus) is acutely angled to right-angled and extends up to one-third of the way to the leaf-base. The margins are irregularly double-toothed, with large coarse teeth, often with rounded to bluntish tips. Venation consists of 5 palmate light green main veins, with irregular lateral veins arising from them and becoming reticulate.

The upper surface is roughish textured, mid-to-dark matt green, with sparse scattered fi ne white or sandy hairs along the veins and in tufts in the main vein-axils near the base. The lower surface is a lighter green to grey-green, sometimes blue-green, with short fi ne light hairs scattered over the leaf surface and concentrated along the veins, especially in the vein-axils. The undersurface can vary from almost hairless to densely covered in velvety down. The conspicuous bright green petioles are strong, round, becoming glabrous, and vary in length, often as long as or longer than the leaves. The petiole bases are kinked and swollen.

 

 

Leaves of Acer velutinum: ▲ ▲ the whole leaf;

▲ the bottom side of a glabrous variant (photos: Hugh Angus); ▼ the bottom side of a tomentose variant (photo: Piotr Banaszczak).

 

 

▲ Flowering branches of A. velutinum (photo: Piotr Banaszczak).

▼ Branch with young fruits of A. velutinum

(photo: Hugh Angus).

The small yellow-green to yellow-white fl owers appear in dense upright to outward-pointing umbel-like clusters, on short hairy peduncles. Each infl orescence of 25-50 fl owers is 8-12cm long and up to 10cm wide, and occurs on a terminal shoot soon after the leaves at the end of May. There is a pair of very small hairy leafy bracteoles at the base of each slender fl ower stalk (pedicel), where it joins the stout hairy central stalk (peduncle). The small male and female fl owers have 5 sepals and petals and 8 stamens, and occur together on the same infl orescence. The sepals are ovate and the petals oblong-ovate, slightly narrower, with both sparsely hairy on the inner surface. The male fl owers have stamens with the long glabrous fi laments holding the anthers well clear of the perianth, and their bases inserted just inside the rim of the receptacle (extrastaminate). The ovary is absent. In female fl owers, the central ovary is downy, and the stamens have very short fi laments so that the anthers stay partly hidden inside the perianth.

FRUITS:

FLOWERS:

The large fruits occur in clusters of 2-10 pairs of samaras connected to a stout central hairy stalk, with long pedicels and the fruits pointing outwards and upwards, never downwards. Each samara (nutlet plus wing) is 4-5cm long, with the pair of wings diverging at angles of 30-100 degrees. The fat round nutlet is 6-7mm in diameter, 4-5mm thick, and covered in short grey- white hairs, especially at the junction with the stalk. The broad papery wings are strongly keeled and veined, with grey-white hairs along the keels (thicker outer edges) from the nutlets, and with broad rounded tips. Each wing is 12-17mm wide at the broadest point in the outer third and reducing sharply to 3-4mm wide at the narrow 'throat' - the junction with the nutlet.

 

 

10 The Maple Society Newsletter ● Autumn/Fall 2021 ● Vol. 31/3

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