Esgueiria futabensis sp. nov., a new angiosperm flower from the Upper Cretaceous (lower Coniacian) of northeastern Honshu, Japan

7 Pages·1999·3.1 MB·English

by  Masamichi Takahashi

©Paleontological Research, vol.3, no.2, pp.81-87, 2Figs., June 30, 1999
by the Palaeontological Society of Japan
Esgueiria futabensis sp. nov., a new angiosperm flower
from the Upper Cretaceous (lower Coniacian) of
northeastern Honshu, Japan
MASAMICHI TAKAHASHI1 PETER R. CRANE2 and HISAO ANDO3
,
'Department of Bioscience, Kagawa University, Takamatsu, 760-8522, Japan
-Department of Geology, The Field Museum, Chicago, Illinois, 60605-2496, U.S.A.
department of Environmental Sciences, Faculty of Science, Ibaraki University, Mito 310-8512, Japan
Received 12 December 1998, Revised manuscript accepted 12 March 1999
Abstract Bulk sieving of samples from the Ashizawa Formation, Futaba Group (lower Coniacian) of
northeastern Honshu, Japan, has yielded a well preserved plant mesofossil assemblage comparable to
those recently described from eastern North America, Europe and central Asia. The most distinctive
component of the assemblage is a new species of the genus Esgueiria (Esgueiria futabensis sp. nov.), a
fossilflower known previouslyonlyfrom the UpperCretaceous(Campanian Maastrichtian)ofPortugal. A
possible additional species of the genus has also been recovered from a second mesofossil assemblage
in the Tamayama Formation (lower Santonian). The occurrence ofEsgueiria in Europe and eastern Asia
during the Late Cretaceous indicates that despite the vegetational differences between these areas
inferred from fossil pollen, some elements were widespread across middle paleolatitudes, presaging the
strong floristic similarities among mid and high latitude regions of the Northern Hemisphere during the
early Tertiary.
Key words Angiosperm flower, Ashizawa Formation, Coniacian, Esgueiria futabensis sp. nov., Santonian,
:
Tamayama Formation
Introduction Materials and methods
Studies of the early fossil history of flowering plants (an- Plant fossils were isolated from two sets of bulk samples
giosperms) have been revolutionized overthe last15years by collected attwodifferent levels in the FutabaGroupexposed
the discovery of abundant, small, well-preserved and sys- in Fukushima Prefecture, northeastern Honshu, Japan. The
tematically informative fossil flowers in assemblages of fossils are small, three-dimensional and charcoalified or
Cretaceous plant mesofossilsfrom Europeand eastern North lignitized mesofossils. The Kamikitaba plant mesofossil
America (e.g., Friis and Skarby, 1982 Friis, 1983 Knobloch asssemblage (sampleF16) was isolated from a poorly sorted,
; ;
and Mai,1984; Friisetal., 1994;Craneetal., 1994). These carbonaceous, black, sandy siltstone collected along a
specimens have yielded important information relating tothe tributary of the Kitaba River in Kamikitaba, Hirono-machi
early diversification of many lineages of extant angiosperms (Study Route B of Ando ef a/., 1995; 3712'N, 14057'E).
and the evolution of their pollination and dispersal biology These samples were from the Asamigawa Member of the
(e.g., Crane ef a/., 1995). Only recently have similar Ashizawa Formation, which is interpreted as alluvial fan
mesofossil assemblages been recognized in central Asia sediments (Ando, 1997). The Kohisa plant mesofossil
(Frumina ef a/., 1995, Frumin and Friis, 1996,1999), and we assemblage (sampleF11), comprised a poorly sorted, beige,
now report that they also occur in eastern Asia. In this sandy siltstone with scattered carbonaceous flecks. It was
paper we describe the most characteristic of several fossil collected along the Kohisa River, Kohisa, Ouhisa machi
flowers in newly discovered plant mesofossil assemblages northeast of Iwaki City (Study Route N of Ando ef a/., 1995
;
from the Futaba Group (lower Coniacian-lower Santonian) of 3710'N, 14057'E). These samples were from the middle
Northeast Japan. part of the Tamayama Formation, which is interpreted as
braided riverflood plain sedimentswith lagoonal facies inthe
uppermost part (Ando, 1997).
The Futaba Group comprises fluvial to shallow marine
82 Masamichi Takahashi ef al.
sediments in the southern Abukuma Belt of NortheastJapan Esgueiria futabensis sp. nov.
(mAonsdtofeofrmaalt.,io1n995in).theThFeutAasbhaiGzraowuap,Foarnmdatiisonoveirsltaihne blyowetrh-e Figures1-1—1-8, 2-1,2-2,2-4,2-5
Kasamatsu Formation, which itself is overlain by the Material— PP45389 (holotype). Other specimens; PP
Tamayama Formation. Based on the occurrence of lower 45390-PP45417.
Coniacian ammonites and inoceramids in the middle of the Type Locality and Horizon.—Kamikitaba plant mesofossil
Ashizama Formation, and a lower Santonian inoceramid assemblage (sample F16), along a tributary of the Kitaba
(Inoceramusamakusensis) in the upper partoftheTamayama River in Kamikitaba, Hirono-machi, (Study Route B of Ando
Formation, the Futaba Group is thought to range in age from ef al. 1995 ; 3712'N, 140'57'E).
early Coniacian to early Santonian. The age of the plant- Etymology.-Named after the Futaba Group, the geologi-
bearing sediments in the Asamigawa Member is probably cal unit from which the specimens were recovered.
early Coniacian (ca. 89 million years before present ; Grad- Specific Diagnosis.—Ovary and fruit narrowly elongate,
stein ef al., 1995), whereas the age of the plant-bearing rounded at the base. Peltate (glandular) trichomes on the
sediments in the Tamayama Formation is probably early base of the styles, and also in rows, often of ten or more, on
Santonian (ca. 85million years before present Gradstein ef the hypanthium. Simple trichomes densely spaced on the
;
al., 1995). surface of the ovary, calyx and styles. Prominent recep-
Bulk samplesofca. 500 kg ofcarbonaceous, black, poorly tacular mounds present between the stamens and the
sorted sandy siltstone were dried in the laboratory, disag- perianth.
gregated in water and sieved through a 0.3mm mesh. Dimensions.—All specimens lacking a well-preserved
Recovered carbonaceous debris was then cleaned in hydro- corolla: length of ovary (1.85) 2.76(-3.3)mm breadth of
: ;
fluoric and hydrochloric acids, thoroughly rinsed in water, ovary: (0.7—) 1.12 (—1.5)mm; length of sepals: unknown;
and dried in air. Individual specimens selected forscanning breadth of sepals: (0.3-) 3.62 (-0.4)mm: 25specimens
electron micrsocopy were mounted on scanning electron measured. Pollen not identified.
microscope stubs, sputter coated with platinum-palladium Description and Remarks.—The species is known from 29
and examined in a Hitachi S 800 field emission scanning complete or fragmentary flowers from the Kamikitaba
electron microscope. All specimens are deposited in the assemblage preserved mainly as charcoalified specimens.
paleobotanical collections of the Field Museum of Natural Similar material from the Kohisa assemblage is not referred
History. Chicago (PP). to E. futabensis, and probably represents a different species
ofEsgueiria (see below). Manyofthespecimensare broken
Systematic description or abraded fragments of the inferior ovary, but almost all
show either the distinctive peltate glands, or the remains of
Class Magnoliopsida (angiosperms) the glands and their secretion in one or more longitudinal
Genus Esgueiria Friis, Pedersen and Crane, 1992 grooves in the ovary wall. None of the specimens is a bud
and most of the material probably represents mature fruits
The genus was established by Friis, Pedersen and Crane with a partially persistent.perianth and androecium. Noneof
(1992) based on material from two localities of Campanian- the specimens has yielded information on inflorescence
Maastrichtian age in the northern part of the Western structure, anthers, pollen or ovules.
Portuguese Basin, Beira Litoral, Portugal. Two species Flower : Flowersareepigynous(Figure1-1)andthecalyxis
were distinguished : Esgueiria adenocarpa from the Esgueira visible in most specimens. Remains of filament and styles
locality (the type species), and Esgueiria miraensis from the bases are also commonly preserved. Unequivocal remains
Mira locality. of the petals are rarely present. None of the specimens
have a pedicel or prophyll preserved.
Perianth The calyx consists of five free sepals (Figure1-
:
2). In all specimens the calyx lobes are broken and their
shape cannot be established reliably (Figures1-2,1-6,2-5).
-> Figure! Esgueiria futabensis sp. nov., Kamikitaba assemblage, Asamigawa Member, Ashizawa Formation (lower
Coniacian), Futaba Group, Fukushima Prefecture, northeastern Honshu, Japan. 1. Holotype, lateral view of well preserved
epigynous flower showing peltate and simple trichomes on the ovary wall, note remains of sepals and three styles atflower
apex, aswell astheprotruding hemispherical glands intheoutertissuesoftheovarywall, PP45389, • 35. 2. Holotype,apex
of flower showing sepals, possible remains of corolla, receptacular mounds, stamen filaments and three styles, PP45389,
x 73. 3. Holotype, detail of small, peltate, trichome from base of style, note also thick wall of broken trichome, PP45389,
930. 4. Lateral view of abraded specimen showing ovary with longitudinal ribs denuded of trichomes, note remains of
sepals and stout style base at the apex of the flower, PP45403, x35. 5. Holotype, detail of peltate and simple trichomes
fromovarywall, notealsotheopening ofahemispherical gland intheovarywall, PP45389, X100. 6. Detailofapical portion
ofspecimen in Figure1-4showing sepals, receptacular mounds, filament bases and stout base ofstyle, PP45403, <72. 7.
Holotype, detail of simple trichome from ovary wall, note verrucate surface, PP45389, 920. 8. Detail of apex offlower in
Figure1-4showing remainsofsepals,ten prominentreceptacularmounds, eight(possiblynine)filamentbasesandstoutbase
of style, PP45403, x72.
Cretaceous angiosperm flower 83
84 Masamichi Takahashi et al.
Figure2. Esgueiha futabenis sp. nov. and Esgueiria sp., Futaba Group, Fukushima Prefecture, northeastern
Honshu, Japan. 1,2,4, 5, Esgueiria futabensis sp. nov., Kamikitaba assemblage, Asamigawa Member, Ashizawa
Formation (lower Coniacian). 3, 6, Esgueiria sp., Kohisa assemblage, middle part of the Tamayama Formation
(lowerSantonian). 1. Lateral view ofabraded specimen showing numerous peltate trichomes intwogrooves inthe
ovary wall, PP45391, 32. 2. Lateral view of abraded specimen showing remains of peltate trichomes in two
grooves in the ovary wall, note remains of sepals and stout base of style at the floral apex, PP45393, 30. 3.
Lateral view of compressed specimen showing three prominent peltate trichomes on the ovary wall, note thatthe
peltate trichomes are larger and fewer than in E. futabensis, PP45419, X17. 4. Detail of specimen in Figure2-1
showing remains of peltate trichomes and unabraded portion of ovary wall, PP45391, 90. 5. Apex of specimen
in Figure2-2showing sepals, basesoftwofilamentsandstoutbaseofstyle, PP45393, • 67. 6. Apexofspecimen
in Figure2-3 showing stamen filament surrounding stout base of style, note remains of receptacular mounds
between the sepals and stamen bases, PP45419, 27.
Cretaceous angiosperm flower 85
However, there are sufficient specimens in which parts of that the trichomes are thick walled (Figure1-3). The tri-
the calyxare preserved to inferthat it was persistentthrough chome wall close to the point of attachment seems to be
fruitdevelopment. The corolla is not clearly visible in anyof thinner and somewhat collapsed (Figure1-7). In well
the specimens, although afewshowfragments oftissuethat preserved specimens the trichome wall is ornamented with
may represent the bases of petals. The rare presence of distinctive elongated Verrucae (Figures1 3,1-7).
the corolla in more than 1,000specimens of £ adenocarpa Peltate trichomes : Peltate trichomes (inferred to have
ledtothe conclusion thatthe corollawasprobablycaducous been glandular) are arranged in a single row in the grooves
(Friis ef a/., 1992), and this may also have been the case in in the ovary wall (Figures1 5,2-4). The peltate trichomes
£ futabensis. never occur side by side. Smaller peltate trichomes also
Receptacular mounds Most specimens show prominent, occur on the style bases (Figure1-3). On the ovary wall the
more or less ellipsoidal m:ounds of tissue, ca. 0.2 mm broad peltate trichomesare typically more or lesscircular, 0.12-0.18
and ca. 0.1 mm deep, on the receptacle betweenthefilament mm in diameter, and appear to consist of a central stalk and
bases and the calyx (Figures1-6,1-8). In one specimen a shieldlike head. A clear radiating structure among the
there are ten mounds that alternate with the stamen bases cells comprising the head has not been seen. The number
(Figure1-8). The nature of these mounds is uncertain, but of peltate trichomes in a single row varies, but it is often
judging from their position and swollen structure (Figures1-2, between 10 and 20 (Figure1-1, 2-1). Frequently, under the
1-6) it is possible that they are nectary lobes. A possible light microscope, the peltate trichomesappearto be embed-
nectarywasobserved in E adenocarpa, but inthe more usual ded in a black shiny substance, which is often present even
postion for a disc nectary, between the stamens and the when the trichomesthemselves are not clearlyvisible(Figure
style bases (Friisefa/., 1992). In £ futabensis it is clear that 2-2). We infer that this represents the remains of a secre-
the receptacular mounds are outside the androecium tion associated with the glandular trichomes. Peltate tri-
between the sepals and the stamens (Figure1-8). chomes also occur on the style bases of well preserved
stAanmdernoperceisuemrv:edNoanned woef hthaevesbpeeecnimuennasblehatsodaeteccotmppollelteen scpheocmiemsenasresgceantetrearleldy asmmaolnlegr (tchae. 0s.i0m6plmemhaiinrsd.iamTehteers)eatnrid-
on any of the flowers. However, the position of the stamen less prominentthan those on the ovarywall but are similar in
filaments indicates stamens were both opposite to, and structure (Figure1-3).
alternatewith, the sepals(Figure1-8). Based onthis pattern
an androecium often stamenswould be inferred. However, Comparison
the best preserved androecium (Figure1-8) shows the
remains of only eight (or possibly nine) filaments. It is Esgueiria futabensis clearly shows the diagnostic features
uncertain whether this indicates incomplete preservation, or of the genus (Friis ef a/., 1992). The flowers are small,
whether less than ten stamens developed as in E. adenocar- epigynous and bisexual with the perianth and androecium
pa (Friis ef a/., 1992). There is no clear indication that organized on a basically pentamerous plan. There is a
stamens were arranged in more than one whorl (Figure1-8). calyx of five free sepals and an androecium with more than
Gynoecium : The ovary is inferior and unilocular. The five stamens. The ovary is unilocular with three styles.
holotype clearly shows that there were three free styles, at The indumentum consists of simple stiff hairs and the
least distally (Figure1-2). Proximally, however the styles characteristic multicellular, peltate trichomes.
appear to have been fused into a single, stout, style base Esgueiria futabensis is clearly distinguished from the two
(Figures1-6,2-5). The ovary is narrowly elongated, more or other species ofthe genus. It differsfrom the type species,
2l-e1ss,2p-a2r)a.lleTl-hseideodvaarnydwwailtlh iasrpoluenadteedd biantsoef(iFviegulroensg1it-1u,di1n-a4l, £mmaderantohcearrptah,anin(1b.5ei)n1g.8g8en(e2r.2a)llmymlalrognegr.: (T1.h8e5)sh2a.7p6e(o—f3t.h3e)
grooves that alternate with sepals, and five longitudinal ovary is also more or less parallel-sided, ratherthan obovate,
ridgesthatare on the same radius asthesepals. The ovary and the base of the ovary is rounded rather than pointed
wall is about0.05 mm thick. In several specimensthereare (compare Figures1 1,1 4,2 1,2-2 with Friis, Pedersen and
protruding hemispherical glands, ca. 0.1 mm in diameter, in Crane, 1992, Plate1). The peltate trichomes are smaller
the outer tissues of the ovary wall. In abraded specimens (0.12 0.18mm in diameter) in £ futabensis than in E.
mm
that lack the epidermis the inner layers of the ovary wall are adenocarpa (0.2-0.3 in diameter). Also significant isthe
seen to be composed of small equiaxial sclerenchyma cells numberof peltateglands in asinglegrooveontheovarywall,
ca 0.01 mm in diameter. Lining the locule there is a inner which is often 10 20 in £ futabensis, compared with a
epidermis of larger cuboidal cells. maximum of five or six in £ adenocarpa.
Trichomes: Two different types of trichomes have been The occurrence of peltate glands on the style bases
observed on the specimens. They are best developed and (Figure1-3) is a further difference between £ futabensis and
most easily observed on the surface of the ovary but also £ adenocarpa, but a similarity with E. miraensis. However,
occSuirmpolne ttrheicshtoomuetss:tySliempblaese.hairs are scattered all over the covoamrpyar(e1.d85to) £2.m7i6rae(n-s3i.s3,)mE.mfutcaobemnpsairsedis ltaorge0r.8:-l0e.n9g5thmmo.f
ovary and other floral organs. The hairs may be up to ca. The ovary of £ futabensis is also long and narrow, rather
0.2 mm long, are more or less parallel sided formuch oftheir than campanulate as in £ miraensis.
length, and appear to be unicellular (Figure1-7). At the Other Esguieria flowers are known from the Kohisa plant
apex they have an acute point. Broken specimens show mesofossil assemblage, which is younger (early Santonian)
Masamichi Takahashi et al.
than the Kamikitaba assemblage that yielded E. futabensis. and sequences. Journal of Geography, vol.104, p.
However, the Kohisa specimens are larger than those from 284-303. (in Japanese)
Kamikitaba (length of ovary [2.75-] 3.5 [-4] mm), are Ando, H., 1997: Apparent stacking patterns of depositional
more obovate in shape with a more pointed base, and also sequences in the Upper Cretaceous shallow-marine to
have significantly larger peltate trichomes (Figures2-3,2-6). fluvial successions, northeast Japan. Memoirs of the
These specimens may representafourth speciesofEsgueir- Geological Society of Japan, vol.48, p.43-59.
ia, but because only eight specimens are known (PP45418- Crane, P. R„ Friis, E. M. and Pedersen, K. R., 1994:
Paleobotanical evidence on the early radiation of
PP45425), they are here left unassigned as Esgueiria sp. magnoliid angiosperms. Plant Systematics and Evolu-
tion, Supplement, vol.8, p.51-72.
Discussion Crane, P. R„ Friis, E. M. and Pedersen, K. R., 1995: The
origin and diversification of angiosperms. Nature, vol.
In terms of systematic affinities, E. futabensis does notadd 374, p.27-33.
to previous discussions of a relationship between Esgueiria Friis, E. M., 1983: Upper Cretaceous (Senonian)floral struc-
and the extantangiosperm familyCombretaceae. However, tures of juglandalean affinity containing Normapolles
..
this new species is important in several respects. It docu- pollen. Review of Palaeobotany and Palynology, vol.
ments the occurrence of mesofossil assemblages with well- 39, p.161-188.
preserved angiosperm flowers in the Upper Cretaceous of Friis, E. M., Pedersen, K. R. and Crane, P. R., 1992: Esgueir-
Japan that are comparable in their quality of preservation to ia gen. nov., fossil flowers with combretaceousfeatures
those recentlydescribed from eastern North America, Europe from the Late Cretaceous of Portugal. Biologiske
annudmbceerntroaflfoAsssiial.anIgtiaodsdpseramnreepwrosdpuecctiievse tsotrtuhcetuvreersyssomaflalr Friis,SkEr.ifMt.er,, Pvoeld.e4r1s,enp.,1-K4.5.R. and Crane, P. R., 1994: An-
giosperm floral structures from the Early Cretaceous of
described from the Upper Cretaceous of Japan (Stopes and Portugal. Plant Systematics and Evolution, Supple-
Fujii, 1910 ; Ohana and Kimura, 1987 ; Nishida, 1985,1991, ment, vol.8, p.31-49.
1994 ; Nishida and Nishida 1988 ; Nishida et al., 1996). It Friis, E. M. and Skarby, A., 1982 : Scandianthus gen. nov.,
also provides the first evidence of botanically informative angiosperm flowers of saxifragalean affinity from the
plant fossil assemblages (other than palynofloras ; Miki, Upper Cretaceous of southern Sweden. Annals of
1977 ; Takahashi, 1988) in the Futaba Group. Botany, vol.50, p.569-583.
The discovery of Esgueiria futabensis also has interesting Frumin, S. and Friis, E. M., 1996: Liriodendroid seeds from
biogeographic implications and extends substantially the the Late Cretaceous of Kazakhstan and North Carolina,
range of a genus previously known only from the U.S.A. Review of Palaeobotany and Palynology, vol.
Campanian-Maastrichtian of Portugal. Based on pollen 94, p.39-55.
and spore assemblages Portugal was part of the Nor- Frumin, S. and Friis, E. M., 1999: Magnoliid reproductive
mapolles Province during the Late Cretaceous. Japan is organs from the Cenomanian Turanian of north-west-
ern Kazakhstan Magnoliaceae and llliciaceae. Plant
generally included in the Aquilapollenites Province (Hern- :
gjerceteanteefgraa/i.,ns19i9n6)LabtaeseCdreotnactehoeusfirsstedaipmpeenatrsanyocuengofertrtiphraon- FrumiASnlyaat,peamjaSat.iIc.(,sTaZaxhnoilddiinaE,vcoeSla.uet)Gi.ons,eaenvdodls. 2Kf1or6ro,cmhpa.tg2hi6en5a,C2e8nI8.o.Am.,an1i9a9n5-:
those of the Futaba Group (Miki, 1977). The occurrence of Turonian of Northern Kazakhstan. Paleontologicheskiy
Esgueiria in both eastern Asia and southern Europe docu- Zhurnal, vol.29 (1A), p.194 202.
mentsthat some Late Cretaceousfloristic elements had very Gradstein, F. M., Agterberg, F. P., Ogg, J.G., Hardenbol, J.,
broad geographic distributions, presaging the strong floristic Van Veen, P., Thierry, J. and Huang, Z., 1995: ATrias-
similarities evident at middle and high latitudes of the sic, Jurassic and Cretaceous time scale. In, Berggren,
Northern Hemisphere during the early Tertiary. W.A., Kent, D.V., Aubry, M. P. and Hardenbol, J., eds.,
Geochronology, time scales and global correlation.
Society of Economic Paleontologists and Mineralogists,
Acknowledgments
Special Publication, vol.54, p.95-126.
This work was supported by Grant-in-Aids (08640891 and Herngreen, G. F.W., Kedves, M., Rovnina, L.V. and Smir-
09640827) from the Ministry of Education, Science, Sports nova, S. B., 1996: Cretaceous palynofloral provinces:
and Culture of Japan to MT., and by fellowships from the a review. In, Jansonius, J. and McGregor, D. C, eds.,
Palynology principles and applications. American
Japan Societyforthe Promotion ofScience in1997 (S-97128) :
Association of Stratigraphie Palynologists Foundation,
and 1998 (S-98106) to PRC. This work was also supported
vol.3, p.1157-1188.
9in61p4a6r7t2btyo PU.RSC..NatPiRoCnalisSalcsioengcraetefFuoluntdoaKtiaognawGaraUnntiveErAsRit-y KnoblForcühc,hteEn„ uannddSMaaim,enD.aHu.,s 1d9e8m4C: eNneoumeanGabtitsunMgaaesntrniacchht
for its hospitality during completion of this research. (Kreide) von Mitteleuropa. Feddes Repertorium, vol.
95, p.1-341.
References cited Miki, A., 1977: Late Cretaceous pollen and spore floras of
northern Japan composition and interpretation. Jour-
:
Ando, H., Seishi, M., Oshima, M. and Matsumaru, T, 1995: nal of the Faculty of Science, Hokkaido University,
Fluvial-shallow marine depositional systems of the SeriesIV, vol.17, p.399-436.
Futaba Group (Upper Cretaceous): Depositional facies Nishida, H., 1985: A structurally preserved magnolialean
Cretaceous angiosperm flower 87
fructification from the mid-Cretaceous of Japan. Y., 1996: A permineralized magnolialean fructification
Nature, vol.318, p.58-59. from the Upper Cretaceous of Hokkaido, Japan.
Nishida, H., 1991 : Diversity and significance of Late Research Institute for Evolutionary Biology, Scientific
Cretaceous permineralized plant remains from Hok- Reports, vol.8, p.19-30.
kaido, Japan. Botanical Magazine, Tokyo, vol.104, p. Ohana, T. and Kimura, T., 1987: Preliminary notes on the
253-273. multicarpellousfemaleflowerwith conduplicate carpels
Nishida, H., 1994: Elsemaria, aLateCretaceousangiosperm from the Upper Cretaceous of Hokkaido, Japan. Pro-
fructificationfromJapan. PlantSystematicsandEvolu- ceedings of the Japan Academy, Series B, vol.63, p.
tion, Supplement, vol.8, p.123-135. 175-178.
Nishida, H. and Nishida, M., 1988: Protomonimia kasai- Stopes, M.C. and Fujii, K., 1910: Studies on the structure
nakajhongii gen. et sp. nov. a permineralized and affinities of Cretaceous plants. Philosophical
:
magnolialean fructification from the mid-Cretaceous of Transactions of the Royal Society, B, vol. 201, p.1-90.
Japan. Botanical Magazine, Tokyo, vol.101, p.397- Takahashi, K., 1988: Palynology of the Upper Cretaceous
426. Futaba Group. Bulletin of the Faculty of Liberal Arts,
Nishida, M., Ohsawa, T., Nishida, H., Yoshida, A. and Kanie, Nagasaki University (Natural Science), vol.28, p.67 183.