Vitaceae in New Jersey

I am not an expert; this is what I've learned so far:

In Vitaceae in New Jersey we have Parthenocissus (quinquefolia, inserta, tricuspidata), Ampelopsis (only glandulosa), and Vitis (aestivalis, labrusca, riparia, vulpina, and those planted in vineyards, which I ignore).

P. tricuspidata is the only one with some leaves three parted. If all leaves are whole, then it's got smaller leaves and leathery and it grows by tendrils tipped in disks. It's also only here where planted, I've seen it spread away from the planting but never show up where there has never a reason to plant it there. But remember if seeing a winter vine on a building with disks it is possibly this (and not necessarily P. quinquefoila)

P. quinquefolia and P. inserta are tough to separate and often can't be in NJ. If disk-tipped tendrils are present it is P. quinquefolia, but their absence does not make it P. inserta. P inserta generally has shinier leaves with longer petiolules, but that is not enough to rule out P. quinquefolia. If the flowers or fruit are present, P. inserta always has dichotomous branching and P. quinquefolia always has a strong central stem (if zig-zagging) to the inflorescence.

P. quinquefolia is far more likely to climb tree trunks than P. inserta. P. inserta generally cannot climb a flat wall at all. P. inserta is much more common in chain-link fences.

Ampelopsis and the Vitis species are tough. Old Ampelopsis vines do not shred. Shredding bark is always Vitis. V. riparia does not have big "knuckles" at the attachment points of the tendrils. The other three grapes do.

Be aware that very old Parthenocissus vines look like Toxicodendron vines (or Hedera vines) but with fewer, lighter, less branched rootlets (but still far more of them than I would expect, given a young vine to compare to).

A. glandulosa has downy/somewhat hairy leaf stems and the newest part of twigs. A. glandulosa is never white or red below. A. glandulosa does not have teeth that are concave on the edges, as V. riparia does. A glandulosa does have big knuckles at all joints, unlike V. riparia (but similar to the vastly less common V. vulpina).

The fruit is key for separating Ampelopsis from Vitis, Ampelopsis flowers and fruit are in umbels, they never have a central stem. Vitis blooms earlier, has flower clusters visible generally from the moment of leaf unfurling, and those clusters always have a central stem (if zig-zagging).

Grape leaves that are reddish or rusty-hairy below are always V. labrusca.

Grape leaves that are white below are V. aestivalis if you can see the texture of the leaf veins below, and V. labrusca if the white wooliness conceals the texture of the underside leaf veins. V. aestivalis is much more common in my experience.

If the grape is green below look at the teeth. V. riparia has concave edges to the leaf teeth, making them "sharper" looking. V. vulpina does not. V. riparia is vastly more common (or I'm mis-IDing a lot of V. vulpina, but I've heard V. riparia described as "abundant").

I have been told that Ampelopsis tendrils fork dichotomously (both halves the same length) and Vitis tendrils do not (one side longer, and more in a straight line with the tendril stem). I can't see it myself.

Ampelopsis will climb kudzu-like over everything and smother it; Vitis does not (it tends to dangle below, and use trees far more than shrubs).

Lähettänyt srall srall, 22. marraskuuta 2020 14:19

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Thanks for posting. There are helpful hints from someone who knows the plants well.

Do you find Vitis labrusca to be somewhat brown tinted below? And Vitis aestivalis white tinted?

Leaf teeth longer than wide, the sides concave, the apices sharp......Vitis riparia
Leaf teeth wider than long, the sides convex, the apices obtuse......Vitis vulpina

Vitis riparia is way more common in NYC also. https://www.inaturalist.org/observations?place_id=674&taxon_ids=119936,126645

Lähettänyt danielatha 10 päivää sitten (Lippu)
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Thanks, @danielatha. V. riparia is by far the most common grape I see. V. aestivalis would be next. Yes, usually V. labrusca is reddish but I've also seen it pretty white, though densly wooly. V. vulpina seems to give me the most trouble, or rather, telling somewhat less sharply-pointed V. riparia from V. vulpina does.

Lähettänyt srall 10 päivää sitten (Lippu)

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