Is this tree leaf evolution?

It seems that you're trying to propse this leaf as comming from some transitional species. Right? Look up "Photobucket" or "ImageShack" for hosting sites that you can link too.I'd like to see the pictures of what you think the leaves should look like.We don't really ever get into plant evolution here.Have you read up on Aceraceae and how they relate to Sapindaceae?You should also read up on Acer negundo because according to that page it seems to be in the Sapindaceae family as opposed to the aceraceae one. But then, according to the page an acer:

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Acer (maple) is a genus of trees or shrubs. They are variously classified in a family of their own, the Aceraceae, or (together with the Hippocastanaceae) included in the family Sapindaceae. Modern classifications, including the Angiosperm Phylogeny Group classification, favour inclusion in Sapindaceae.

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So who really knows?

Welcome to EvC.So... what is the problem with the leaves that makes you think of evolution?

I think that some of the leaves don't look like maple leaves....Like this one: Did they all come from the same tree?and this one: ...looks like it came from some kind of freak.So, looking it up on wiki I see:

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Unlike most other maples (which usually have simple, palmately lobed leaves), Acer negundo has pinnately compound leaves that usually have three to seven leaflets. Simple leaves are also occasionally present; technically, these are single-leaflet compound leaves. Although some other maples (such as A. griseum, Acer mandshuricum and the closely-related A. cissifolium) have trifoliate leaves, only A. negundo regularly displays more than three leaflets.

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So yeah... might just be a normal tree. For something to not be evolving it is said that it is in stasis.Technically, all species are in a constant flux, check out genetic drift, so they are always in a transitional stage. You seem to think that stasis is the default but its not.Check out this that I found too: Neat, huh?

Right on! Like I said upthread, we rarely talk about the evolution of plants.I cannot seem to find much info on maple evolution....I did find this though:

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Evolution:
An angiosperm, the earliest known Acer (A. amboyense) was found in eastern North America from the fossil remains of the late Cretaceous period about 67 MYA. All maple fossils have been located exclusively in the Northern Hemisphere and the trees seem most abundant during the Miocene (Oterdoom 1994).

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The closest fossil relative to A. macrophyllum appears to be A. merriamii Knowlton (or A. oregonianum Knowlton) from the Late Miocene around 5 MYA (Macginitie 1969; Oliver 1934). Macginitie (1969) notes the potential for a taxonomic problem with assigning the name of a fossil species to a living species, for although they may be morphologically similar it is difficult to determine if the species are genetically identical.

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The flowering and sexual mating of Acer have ranged from wind-pollinated to insect-pollinated and monoecy to dioecy. A. macrophyllum is an insect-pollinated dicot in which female flowers occur before male flowers (Oterdoom 1994).

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The form of the leaves in the Acer genus has changed over time. From the Late Oligocene to the Early Pliocene (from around 23 to 5 MYA, including the Miocene) the leaf form evolved from the originally more common 3-lobed maples to 5-lobed maples, as evidenced in the paleobotanical studies of the broadening of the A. tricuspidatum leaf base (Oterdoom 1994).

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A. macrophyllum belongs to the deciduous maple Aceraceae family, which has 200 species distributed among 2 genera (van Gelderen et al. 1994). Acer species is believed to have originated in central and western China although no fossils have been located in this area (Oterdoom 1994).

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Cladistic analysis has concluded that the Aceraceae family was formed by earlier members of the Sapindaceae like Bohlenia, which was characterized by loss of a stipule and a locule, as well as a change to opposite from alternate leaves. The Dipteronia line of the Aceraceae seems to be more closely related to the Sapindaceae ancestor Bohlenia, except for a change in the secondary venation of its pinnately compound leaves. The A. arcticum line resulted in an actinodromous maple leaf after the fusion of a minimum of three leaflets (Stewart & Rothwell 1993; van Gelderen et al. 1994).

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Found HERENo problem, I'm happy that I could. Welcome to EvC.

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Science has failed our world.
Science has failed our Mother Earth.
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