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and 7 secondary veins that alternate between forking near the vein tip before reaching the blade margin, and curving upwards near the tip to join the next secondary vein up. The forking secondary veins brace the sinuses between the teeth on the blade margins. Overall, the teeth of the leaflets are large and simple, though the largest of the teeth have two smaller subsidiary teeth. The terminal leaflets on the type specimens are incomplete, so length and width of them is not known. They have a symmetrical leaflet base that is acute in shape, the blade being an inverted v shape. The leaves have tertiary veins that form either a mix of acute angle-right angle structuring or right angle-right angle structuring with the veins spaced 0.7โ1.3 cm (0.28โ0.51 in) apart. The quaternary veins form a network of areoles that are irregular polygons. As with other species of
554:
angle of 30ยฐ. There is a thick vein running along the apical side of the nutlet and 7 loosely grouped veins running up the outer edge of the wing. The wing is 1.2 cm (0.47 in) long and 0.7 cm (0.28 in) wide with the outer edge broadly curving, and with undulating veins that diverge from each other at angles between 5ยฐ and 10ยฐ. The veins curve slightly between leaving the proximal vascular group and reaching the inner wing margin, forking along the way.
117:
544:
veined and ranging between 1.5 and 4.8 cm (0.59 and 1.89 in) in length. The leaflet blades rest against the primary vein of the leaf, lacking petiolules, and have an asymmetric base flaring out on the basal side while remaining narrow on the apical side. Each lateral leaflet has between 5
553:
with a basal nutlet and apical wing. The nutlets are lanceolate in outline with a narrow rounded apex, and a convex basal side. The nutlet is 1.0 cm (0.39 in) long by 0.4 cm (0.16 in) wide, with a 0.4 cm (0.16 in) scar where the fruit attached to a second fruit at an
325:
aged, outcrop of the Beaver Creek flora in
Central western Montana. Although it is located north of the Ruby Flora, which outcrops in southwest Montana, the similarities in overall floral composition between the Beaver Creek, Ruby, and other Montana floras are interpreted by Wolfe and Tanai to
405:
496:, being notably curved along the upper margin of the wing, but the undulating wing venation is not seen in either section, rather is most often seen in
651:
712:
702:
591:
717:
697:
468:. The modification of the leaves into three leaflets due to deep lobation that reaches the primary vein is seen in both sections.
362:
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in the size of the areoles, the shape of the margin teeth, and the morphology of the leaflet bases. The fruits of
722:
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differs from extant members of those sections in that the leaflets do not attach to the primary vein with a
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holotype specimen, number UCMP 9311 A & B, along with paratype leaf and paratype fruit were part of the
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619:
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but are sessile with the leaflet base abutting the primary vein. the species is more similar to extant
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Journal of the
Faculty of Science, Hokkaido University. Series 4, Geology and Mineralogy
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is represented by a fossil specimens that were recovered from a late Eocene, possibly
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358:
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253:
63:
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has leaf and fruit morphologies that Wolfe and Tanai considered similar to both
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in nature. The age of the Ruby flora is considered to range from approximately
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38:
32:
322:
190:
83:
48:
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where the type locality for the species is. At the time of description the
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504:. Wolfe and Tanai noted they were uncertain of the section placement for
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78:
73:
58:
53:
43:
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351:, meaning a probable similar age for the Beaver Creek assemblage.
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are divided into three leaflets, with the lateral leaflets
369:. They determined that fossils belonged to an undescribed
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Journal of the
Faculty of Science, Hokkaido University
626:
596:(maples) in the Cenozoic of Western North America"
412:, the Beaver Creek assemblage had five additional
406:University of California Museum of Paleontology
363:United States Geological Survey, Denver office
592:"Systematics, Phylogeny, and Distribution of
524:lived in North America during the Eocene and
8:
298:. It is tentatively placed into the living
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577:
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528:was a possible candidate for that species.
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20:
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508:, but had inferred an ancestor of both
294:sediments exposed in the US state of
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606:(1): 23, 74, 75, 240, & plate 4.
354:The fossils were first studied by
326:indicate that the assemblages are
14:
373:species and published their 1987
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590:Wolfe, J.A.; Tanai, T. (1987).
713:Extinct flora of North America
1:
703:Fossil taxa described in 1987
408:collections. In addition to
290:. The species is known from
718:Flora of the Rocky Mountains
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314:History and classification
279:described from a group of
240:
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112:Scientific classification
110:
23:
698:Plants described in 1987
16:Extinct species of maple
398:Lincoln County, Montana
365:and Toshimasa Tanai of
349: million years ago
342: million years ago
335: million years ago
396:is in recognition of
419:Acer castorrivularis
488:are also closer to
367:Hokkaido University
226:A. lincolnense
256:& Tanai, 1987
680:
679:
665:Open Tree of Life
620:Taxon identifiers
549:the fruits are a
416:species in 1987;
337:to approximately
261:
260:
730:
723:Flora of Montana
673:
672:
660:
659:
647:
646:
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628:Acer lincolnense
615:
608:
607:
587:
425:Acer florissanti
375:type description
350:
343:
336:
319:Acer lincolnense
265:Acer lincolnense
249:
247:Acer lincolnense
245:
120:
119:
105:
35:
29:Temporal range:
25:Acer lincolnense
21:
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437:Acer salmonense
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344:or as young as
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538:A. lincolnense
536:The leaves of
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526:A. lincolnense
506:A. lincolnense
486:A. lincolnense
470:A. lincolnense
450:A. lincolnense
410:A. lincolnense
402:A. lincolnense
389:of the chosen
379:A. lincolnense
356:paleobotanists
315:
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275:in the family
268:is an extinct
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708:Eocene plants
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479:
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467:
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443:Acer tiffneyi
439:
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391:specific name
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359:Jack A. Wolfe
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235:Binomial name
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142:Tracheophytes
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431:Acer milleri
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148:
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24:
18:
532:Description
394:lincolnense
277:Sapindaceae
201:Sapindaceae
155:Angiosperms
33:Late Eocene
687:Categories
558:References
522:Cissifolia
494:Cissifolia
482:Cissifolia
466:Cissifolia
323:Chadronian
307:Cissifolia
191:Sapindales
643:Q29561154
542:pinnately
387:etymology
219:Species:
125:Kingdom:
637:Wikidata
514:Indivisa
502:Indivisa
500:section
464:section
456:section
197:Family:
168:Eudicots
670:7642082
657:9019916
474:petiole
458:Negundo
385:. The
381:in the
361:of the
303:section
296:Montana
273:species
244:†
223:†
207:Genus:
187:Order:
129:Plantae
100:↓
551:samara
520:sect.
512:sect.
492:sect.
480:sect.
440:, and
328:coeval
292:Eocene
288:fruits
284:leaves
281:fossil
181:Rosids
693:Maple
270:maple
254:Wolfe
175:Clade
162:Clade
149:Clade
136:Clade
652:GBIF
594:Acer
547:Acer
516:and
498:Acer
462:Acer
460:and
454:Acer
414:Acer
377:for
371:Acer
300:Acer
286:and
212:Acer
39:Pre๊
689::
667::
654::
639::
604:22
602:.
598:.
566:^
518:A.
510:A.
490:A.
478:A.
446:.
434:,
428:,
422:,
347:32
340:34
333:38
310:.
177::
164::
151::
138::
89:Pg
94:N
84:K
79:J
74:T
69:P
64:C
59:D
54:S
49:O
44:๊
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