Repurposing LNG terminals for Hydrogen Ammonia: Feasibility and Cost Saving
Fossils attributed to_the_orchidaceae
1. Fossils Attributed to the Orchidaceae
RUDOLF SCHMID AND MARVIN J. SCHMID1
INVESTIGATORS INTERESTED IN the evolutionary history of a family
desire to have information from the fossil record to provide
(hopefully) unequivocal evidence for the early history of that
family. Unfortunately for orchidologists, the known fossil record
of the Orchidaceae is extremely meager. We decided to summarize
what is known of the fossil record of orchids (a) because there are
no accounts available other than the rather superficial ones by
Darrah (15) and Krackowizer (27a, 28) , (b) because there are number
of misconceptions in the literature that should be corrected,
and, most importantly, (c) because a reasonably complete list of
fossils attributed to the Orchidaceae could be prepared since we had
access to the Compendium Index of Paleobotany (see 3, 19 for
accounts of its coverage) and to libraries with extensive holdings
in rather obscure publications.
Most persons seem to favor a relatively great age for the
Orchidaceae (e.g., 1, 5, 6, 12, M, 15, IS, 21-23, 48), but relatively
few have ventured a specific time and/or place of origin. Garay (21-
23), following Stebbins (48, pp. 501-502), postulates an origin in
the early Cretaceous- and in addition proposes Malaysia as the
most likely cradle of orchidhood. Leon Croizat (pers. comm.,
1972) believes that the orchids arose "surely not later than the
earliest Cretaceous. Brieger (5, 6) favors the early Tertiary and the
"united Asiatic-American" tropics (6, p. 329, specific area not
indicated). In contrast, some authors, notably Schultes, believe
that the orchids may be "a comparatively young group" (44, p. 1;
45, p. 1043). While there is some dispute as to the exact time of
origin of the family, nearly all workers (e.g., 5, 16, 17, 21. 40, 44)
seem to agree that currently, and in the immediate past, the
Orchidaceae are in a very active period of evolution.
Most workers have indicated either that there is no fossil record for
the Orchidaceae (e.g., 1, 6, 10, 12, 13, 20, 24) or that there are
only doubtful orchidaceous fossils (e.g., 15, 16, 18, 21, 25, 32-34,
36, 39, 40, 42, 44, 45). In contrast, a few persons (e.g., I I , 26, 28,
35, 38, 43, 49, 50, 52) have stated that valid orchid fossils exist.
Most of these authors apparently based their view concerning the
fossil record of the Orchidaceae chiefly or only on knowledge of the
very dubiously orchidaceous Protorchis monorchis and Palaeorchis
rhizoma described by Massalongo (31-34) from the Eocene of
Italy. 4 Nevertheless, a number of other fossils have also been attributed to
the Orchidaceae, most significantly Straus' (49, 50) three species of
putative orchid fruits (Orchidacites) from the Pliocene of Germany. With
the exception of Gothan and Weyland (26), Kirchheimer (27), and Melchior (35),
however, most recent workers seem unaware of Straus' finds. These and other
taxa will be discussed in detail below.
2. Table 1. Geologic time scale (pre-Mesozoic omitted). (After Hartland, et.al.
26a)
Era Period Epoch Beginning of interval
(in millions of years
Holocene (Recent) 0.005
Quaternary Pleistocene (Glacial) 2.5
Pleiocene 7
Miocene 26
Oligocene 38
Eocene 54
Cenozoic Tertiary Paleocene 65
Cretaceous 136
Jurassic 190
Mesozoic Triassic 225
Orchids are not favorable candidates for fossilization, an obvious conclusion
that has not escaped previous authors (e.g., 15, 18, 28, 40. 44). The following
characteristics of most Orchidaceae probably account for their scarcity as
fossils: (a) predominant occurrence, both in the present and presumably in the
distant past, in the wet tropics, which are areas of rapid decay; (b) herbaceous
habit; (c) epiphytic habit, which would generally preclude orchids from the
conditions (usually aquatic) most conducive to fossilization (see also 15) ; (d)
production of pollinia (usually) rather than individual pollen grains, and
dispersion of the former by animal vectors instead of wind: and (e) minute,
easily degradable seeds.
Krackowizer (28) and Schimper and Schenk (43), however, apparently
believed a rather extensive fossil record of the Orchidaceae is to be expected,
and Darrah (15) and also Krackowizer (28) suggested that fossil orchids might
eventually be encountered in deposits in tropical areas when these become
better known.
Fossils that have been attributed to the Orchidaceae (or to the
Protorchidaceae) are strictly megafossils (e.g., fruits, leaves, tubers, etc.);
orchidaceous microfossils (e.g., seeds and pollen) have not been reported in the
literature. Discoveries of cuticular remains (as those already found of the
Pliocene Orchidacites wegelei of Straus, HI) perhaps offer the best hope for
significant additions to the fossil record of (he Orchidaceae.
Although there is no record of fossil orchid pollen, even if orchid pollen
were preserved as fossils, it is a moot point that it would be recognizable as
such. Botanists simply might not recognize the fossilized pollen of those
orchidaceous forms that had not yet evolved pollinia. Perhaps significantly, the
Asclepiadaceae, which like the Orchidaceae possess pollinia, are not listed in
Potonie's (41) recent compendium of fossil pollen and spores. Although
Chandler's (9, and works cited therein) extensive investigations (initially with
the late Eleanor M. Reid) of the Tertiary London Clay Flora of England
over a period of several decades failed to reveal any orchidaceous remains,
3. she suggested (8, p. 29) that "possibly search for pollen among the finer
sediments and residues may eventually demonstrate the presence of this family"
in the London Clay Flora. Subsequent palynological work (two 1961 Ph.D.
theses by Ma Khin Sein and Jane Pallot at the University of London, both
cited in 9, the latter published as 30) , however, has thus far failed to
substantiate this prediction.
As recently discussed by Eyde (19), there are several paths into the
paleobotanical literature. We checked a variety of sources for records of
orchidaceous fossils, most importantly the index by Andrews (3, including
unpublished cards for additions since 19(>5) and the United States Geological
Survey's Compendium Index of Paleontology, an unpublished file available for
consultation only in the Natural History Building, Room W-300, of the
Smithsonian Institution, Washington, D. C. (see 3, 19) . We checked the
Compendium Index for most of the temperate genera listed in Schultes and
Pease (46). Most tropical genera, however, were not sought in the
Compendium Index due to the minuscule yield that could only result from
such a mountain of effort. As noted above, tropical plants are unlikely
candidates for fossilization. In addition, most tropical orchids are endemics
that presumably evolved during the Quaternary, and hence any fossils of them
would be unlikely to be encountered by paleobotanists, most of whom have
worked (until very recently, at least) in temperate areas. Finally, any
orchidaceous fossils of the pre-Quaternary tropical floras of presently temperate
areas would probably be given generic names not based on living taxa.
5
REPORTS OF ORCHIDACEOUS FOSSILS
Three extinct genera (Palaeorchis, Protorchis and Orchidacites) have been
designated as orchidaceous or protorchidaceous. At least one other fossil taxon,
Antholithes pediloides, has been regarded as an orchid. In addition, fossil
remains from the Quaternary have been attributed to a number of extant,
north temperate orchid taxa. Purists who restrict "fossils" to pie-Quaternary
remains and therefore regard Pleistocene finds as "subfossils" may object to the
inclusion of plant remains from the Quaternary in the following enumera-
tion:
Jurassic
The Compendium Index of Paleobotany, citing Thurmann (51) , lists the
following extant species as occurring in the Jurassic strata at Porrentruy,
France: Ophrys myodes Jacq., Orchis morio L., O. pyramidalls I,., Satyrium
viride L., and Serapias rubra L. This is incorrect. Thurmann did indeed list
these species, but only as part of the modern vegetation of this region.
Eocene
Protorchis monorchis Massalongo (31-33) and Palaeorchis rhizoma (.Massalongo)
Massalongo (32) (= Protorchis rhizoma Massalongo, 31): These species represent
the first described and also the geologically oldest fossils that might possibly
represent orchids. In 1857 Massalongo (31) listed, without benefit of description
or illustration (hence nomina nuda) , the new generic name Protorchis, with
two new species P. monorchis and P. rhizoma based on specimens from the
calcareous Eocene deposits at Monte Bolca, Italy. Massalongo had only
four specimens at his disposal — three of the former species, one of the latter
(33, 34). In 1858 Massalongo (32) validly published Protorchis monorchis and
also the new combination Palaeorchis rhyzoma (the specific epithet is an
orthographic error) based on Protorchis rhizoma. The next year a more
complete description and also a photograph (see Fig. 1) of Protorchis monorchis
were published (33). In his 1858 work Massalongo dated Protorchis as "1851"
with the added notation "in lit.” et in Musaeo" (32, p. 749). Since the 1854
reference is obviously unpublished, the nomina nuda in the 1857 report (31)
thus represent the actual first (though taxonomically invalid) publication of
4. the names involved.
Although Massalongo (31) initially listed his new species under the
Orchidaceae, he subsequently (32-34) very carefully indicated the tentatively
orchidaceous nature of his fossil specimens by including them in a new taxon,
the Protorchidaceae ("Protorchidee" in 32, 33; or the Latinized
"Protorchideae" in 33, 34). Massalongo (32, 33) admitted that he was unable
to find in the extant flora counterparts of his fossils. Massalongo (32, 33) noted
a resemblance of both his fossil species to the Araceae, which he apparently
regarded as being rather close to the Orchidaceae (32). A superficial likeness
between Palaeorchis rhizoma and the fossil alga Delesserites was rejected when
he decided on the affinities of the former (32). After additional concern that
Palaeorchis rhizoma might be butomaceous, Massalongo (32) finally decided
to retain this species in his Protorchidaceae. This discussion illustrates
the difficulty Massalongo had in assigning his fossils to an extant plant
group. This fact is apparently realized by very few authors since a number
(e.g., 15, 18, 28, 42) incorrectly state or imply that Massalongo had regarded
his fossils as orchids.
5. According to Massalongo (32, descriptive terminology below is his) , the
Protorchidaceae are next to the orchids and the aroids and consist of small
herbs with tubers or rhizomes bearing lateral fibrous roots and several very
slender, cuneate-obovate or spathulate leaves with entire margins and fine
midribs. Misstatements to the contrary (15, 25, 26, 28, 43), both species do not
possess tubers. Protorchis monorchis (FIGURE 1) has a round, solitary tuber
whereas Palaeorchis rhizoma (never illustrated by Massalongo) differs chiefly
in having a perpendicularly cylindrical rhizome covered with circular,
papillate leaf scars (32). The two species also differ somewhat in having
spathulate versus oblong to spathulate leaves, respectively (32). Massalongo
(33) subsequently indicated that Protorchis monorchis, of which three speci-
mens were available (33), strictly speaking does not have a true tuber, but rather
a rounded rhizome (FIGURE 1). In the same publication he (33) also added the
6. following information for Protorchis monorchis: tuber 7-8 mm in diameter;
leaves 3-4 per plant, attenuate into a petiole, 5 cm long, and 12-15-18 mm
wide.11 Although Massalongo (34, p. 133) finally indicated that specimens of
both this species and Palaeorchis rhizoma are seedlings, there is no mention in
his previous descriptions (32, 33) of the probable developmental age of these
fossils.
Most workers, usually referring only to Protorchis monorchis, have
subsequently concluded that Massalongo's fossils are not truly representative
of the Orchidaceae (e.g., 15, 18, 21, 25, 26, 35, 39, 40, 42). Schimper and Schenk
(43) , however, accepted Massalongo's finds as orchidaceous, and van der Pijl
(39, 40) apparently seems tempted to accept Protorchis monorchis as validly
orchidaceous, no doubt because its Eocene date ties in with his understanding
of the evolution of the bees. Meschinelli and Squinabol (3i) included both of
Massalongo's fossil species under the Protorchidaceae in the order Micro-
spermae (= Orchidales), but these authors noted that Palaeorchis rhizoma is
probably a member of the Butomaceae. Krackowizer (28) 7 accepted the views of
Meschinelli and Squinabol (36) except that he regarded Protorchis monorchis
as a true orchid rather than as a protorchid. Admitting that both of
Massalongo's fossils are doubtfully orchidaceous, Leslie A. Garay (pers. comm.,
1972) nevertheless maintains that of all the fossils attributed to the
Orchidaceae, Protorchis monorchis is perhaps the most likely candidate for
inclusion in the family, largely because of its similarity to Orchis pallens L.
In conclusion, the orchidaceous nature of Massalongo's fossils is clearly very
questionable. As has already been suggested (Chester A. Arnold, pers. comm.,
1967; 15, 18), perhaps the most charitable tiling that can be said about the
affinity of Protorchis and Palaeorchis is that they are monocotyledonous.
Oligocene
Antholithes pediloides Cockerell (1 1): T. D. A. Cockerell, the prolific
describer of fossils from the western United States,8 in 1915 delineated from
the Lower Oligocene (the age according to MacGinitie, 29; incorrectly
regarded as Miocene by Cockerell, I I ) beds at Florissant, Colorado, a new
species in the fossil artificial (or form) genus Antholithes. Cockerell attributed
the fossil (FIGURE 9), A. pediloides, to the Orchidaceae because of its marked
resemblance to the lip of Cypripedium, and he also presumed that the several
small "subhyaline" spots scattered over the surface might represent the work
of some insect. Other than the suggestive outline of the fossil, however, the lack
of significant detail makes Cockerell's determination extremely doubtful. In
his classic flora of the Florissant beds, MacGinitie (29) reached the same
conclusion and disposed of A. pediloides among "species of somewhat doubtful
taxonomic value" (p. 159) under incertae sedis
.
Miocene
Darrah (15) briefly discussed, and then discounted as truly orchidaceous, a
fossil stem (apparently unnamed) from the Miocene of Hungary that had been
described by a Robert Brown (there were several Robert Browns). Since
Darrah provided no references in his note, and since alter considerable
searching we have been unable to locate any additional information
concerning this fossil, we can only quote Darrah (15, p. 149) fully:
"A third form [besides Massalongo's Protorchis and Palaeorchis] was
once provisionally accepted as a fossil orchid. This fossil stem, found in
rocks of Miocene age in Hungary, included a few structurally preserved
hair-like roots which Robert Brown considered to be of some epiphytic:
orchidaceous plant. . . .
As a matter of fact it was with this organ [the pseudobulb] that Robert
Brown attempted to compare his supposed fossil from Hungary."
7. Pliocene
Orchidacites orchidioides Straus (49), O. wegelei Straus (49), and O.
cypripedioides Straus (50): In 1954 Straus (49) described from the Upper
Pliocene of Willershausen, Germany, two species of fruits, Orchidacites
orchidioides and O. wegelei which he assigned to the Orchidaceae. The two
species, especially the former (as suggested by i t s name), were thought to
resemble various species of Orchis (49). More recently, Straus (50) provided
for Orchidacites a generic diagnosis, which had been omitted from the 1954
report, and described a third species, O. cypripedioides, with fruits regarded
as similar to those of Cypripedium. These taxa are illustrated in FIGURES
2 to 8, reproduced from Straus' more recent paper (50). Orchidacites
is a form genus proposed for fossil fruits comparable to the capsules
of various extant orchid genera (50). According to Straus (50), the
fossil capsules, 1.5 to 2.5 cm long, are ellipsoidal or narrowly ellipsoidal and
have several longitudinal striae (FIGURES 2-8); the remnants of a corolla often
occur at the fruit apex (FIGURES 2-4).
Straus (50, also pers. comm., 1972) believes that the fossil fruits of
Orchidacites came from epiphytes growing on rotting branches that eventually
were blown into the sediments by wind, and, as a consequence, he has
speculated (50, pers. comm., 1972) that many of the present-day orchids (e.g.
Limodorum, Neottia, Corallorrhiza, and Cypripedium) were primitively
epiphytic and now are terrestrial "secondary relicts." This view, of course, is
dissonant with the conventional one that the terrestrial habit is ancestral and
the epiphytic derived (e.g., 5, 6, 16, 17, 21-23, 39, 42).
The Straus fossils have received little comment from either orchidologists or
paleobotanists. Melchior (35) and Gothan and Weyland (26) accepted the
fossils as unmistakably orchidaceous. Kirchheimer (27, p. 650), however,
remained skeptical, believing that the inferior, wing like, ribbed gynoecium
with a distinct styloid process evokes resemblances to young fruits of Halesia,
Pterostyrax and other Styracaceae (a completely unrelated family in the
dicotyledons). Straus (pers. comm., 1972), in counterargument, however,
believes that the fruits he described are truly orchidaceous since fruits of the
Styracaceae never show floral remains whereas fruits of the Orchidaceae often
do.
On examining the photographs reproduced herein ( FIGURES 2-8), Garay
(pers. comm., 1972) is also disinclined to accept Straus' fossils as orchidaceous
because of the curious 3-pronged floral remnants (interpreted by Garay as
a column) ( FIGURES 2-4) and because of the apparently excessive number of
ribs ( FIGURES 2-8) for true orchid fruits (which have a maximum of six).
Robert L. Dressier (pers. comm., 1972) is of a similar opinion, although he is
less certain in excluding Orchidacites cypripedioides (FIGURES 5-8) from the
orchids since the fossil "looks rather like a Cattleya fruit."
In defense of Straus, we should note that a 3-pronged calyx of fused sepals
occurs in some modern taxa (e.g. Pterostylis. see FIGURE 84 in 40: Masdevallia,
etc.) and that on orchid fruits a greater number of ribs (than six) may be
apparent since these may be variously secondarily divided (e.g., Trichopilia
suavis Lindl. et Paxton). Unfortunately, Straus (50) hurts his own cause by
interpreting the floral remnants (FIGURES 2-4) as a corolla, but it is perhaps
more likely that they represent a calyx.
Quaternary
Quaternary orchid fossils are included here for completeness, although they
are unimportant from the viewpoint of our understanding of the origin and
most of the subsequent evolution of the family. The names of at least 20 extant
species of orchids are listed in the Compendium Index of Paleobotany and are
8. attributed to both the Pleistocene and Holocene (= Recent or Postglacial) of
the Quaternary. Most of these listings were compiled around the turn of the
century, when the Compendium Index included casual, incidental references
to fossils - a practice long discontinued ( 1 9 ). Unfortunately, a number of
these listings are not applicable because the original works discuss the various
orchid species as components of the contemporary flora and not as fossils. This
is the case with reports of Goodyera repens (L.) R. Br. from the Quaternary of
Denmark, Himantoglossum hircinum (L.) Sprengel and Ophrys aranifera
Huds. from the Postglacial of Switzerland, and Malaxis paludosa (L.) Sw. from
the Holocene of Germany, which the Compendium Index attributes to
Anderson (2), Naegeli (37, as cited in 7), and Becker (4), respectively.
The Compendium Index also attributes the following extant orchid taxa to
Sernander's (47) extensive work on the Quaternary (Wiirm Glacial and
Postglacial) of Gotland, Sweden (names listed as they appear in Sernander):
Anacamptis pyramidalis (L.) Rich., Cephalanthera ensifolia (Sw.) Rich.,
Corallorrhiza innata R. Br., Epipactis palustris (L.) Crantz, Gymnadenia
conopsea (L.) R. Br., G. odoratissima (L.) Rich., Listera cordata (L.) R. Br.,
L. ovata (L.) R. Br., Malaxis monophyllos (L.) Sw., Neottia nidusavis (L.)
Rich., Orchis angustifolia Wimm. et Grab., O. maculata L., O. militaris L., O.
ustulata L., Platanthera bifolia (L.) Rich., and Sturmia loeselii (L.) Reichb.
However, Sernander (47) merely discusses these and other orchid species in
terms of a phytosociological survey of the modern bog vegetation of Gotland.
The bogs Sernander studied did indeed contain identifiable fossils, but none
of these were orchids.
To our knowledge, there is only one report of a Quaternary fossil attributed to
the Orchidaceae. In 1965 Vent (52, p. 200) described leaf and fruit
impressions from the Riss-Wurm Interglacial of Weimar-Ehringsdorf, Germa-
ny, and assigned these to "cf. Epipactis palustris (Mill.) Crantz" in the
Orchidaceae. Garay (pers. comm., 1972) , however, discounted the orchidaceous
nature of these fossils after examining Vent's photographs (FIGURE 10) .
SUMMARY
Fossils dating from the Eocene to the Quaternary have been attributed to the
Orchidaceae, but objections have been raised against the orchidaceous nature
of all of these fossils. The most likely orchid fossils, nevertheless, remain
Massalongo's famous fossils from the Eocene of Italy — Protorchis monorchis
and Palaeorchis rhizoma — and especially Straus' recent finds from the
Pliocene of Germany Orchidacites orchidioides, O. wegelei and O.
cypripedioides. In conclusion, then, the Orchidaceae have no positive fossil
record and in this sense present a striking parallel to two well-known gods of
mythology: Athena, who sprang fully grown and fully armored from the head
of Zeus; and the Aztec Huitzilopochtli, who was borne fully grown and fully
armored from Coatlicue.
Acknowledgements: This study was carried out while the senior author was the
recipient of a Smithsonian Institution postdoctoral fellowship. We thank Norris
H. Williams and Leslie A. Garay for valuable discussions.
REFERENCES
(1) Ames, O. and D. S. Correll. 1952-53. Orchids of
Guatemala, Heldiuna: Rot. 26:-i-xiii. 1-727.
(2) Andersson, G. 1906. Die Entwicklungsgeschichte der
skandinavischen Flora. Pp. 45-97 in Resultats Set. Congr.
Int. Dot., Vienne, 1905.
(3) Andrews, H. N., Jr. 1970. Index o£ generic names of
fossil plants, 1820-1965. U.S. Geol. SURV. Bull.. 1300.
(4) Becker. G. 1874. Botanische Wanderungen durch die
9. Sümpfe und Torfmoore der Niederrheinischen Ebene. Verh.
Nalurhist. Vereines Preus* Rheinl. Westphallens 31:137-158.
(5) Brieger, F. G. 1958. On the phytogeography of orchids.
Pp. 189-200 in Proc. 2nd World Orchid Conf., Honolulu,
1957.
(6) Brieger, F. (1960. Geographic distribution and
phyllogeny [sic] of orchids. Pp. 328-333 in Proc. 3rd World
Orchid Conf.. London. I960.
(7) Brockmann-Jerosch, H. 1910. Die Änderungen des Klimas
seit der grösstcn Ausdehnung der letzten Eiszeit in der Schweiz.
Pp. 55-71 in Die Veränderungen des Klimas seit dem
Maximum der letzten Eiszeit, Ber., Exekutivkomitee
I I . Int. Geol.-Kongr., Stockholm. 1910.
(8) Chandler. M. E. J. 1951. The Lower Tcrtiary floras
of southern England. I. Palaeocene floras: London Clay
Flora (supplement). London: British Museum (Natural
History). [Text and plates separately bound.]
(9) Chandler, M. E. J. 1964. Idem. IV. A summary and
survey of findings in the light of recent botanical
observations. London: British Museum (Natural
History).
(10) Chesters, K. I. M., F. R. Gnauck and X. F. Hughes.
1967. Angiospermae. Pp. 269-288 in V. B. Harland et al.
[eds.], The fossil record. London: Geological Society of
London.
(11) Cockerell. T. D. A. 1915. Notes on orchids. Bot. Gaz.
59:331-333.
(12) Correll, D. S. 1950. Native orchids of North
America. Waltham, Mass.: Chronica Botanica Co.
(13) Coulter, J. M. and C. J. Chamberlain. 1903.
Morphology of angiosperms. New York: II. Appleton and
Co.
(14) Croizat, L. 1961. Principia botanica. Caracas: The
Author. [1 vol. in 2.] [Published 1961.]
(15) Darrah. W. C: 1940. Supposed fossil orchids. Amer.
Orchid Soc. Bull. 9:149-150.
(16) Dodson. C. H. and R. J. Gillespie. 1967. The biology
of the orchids. The Mid-America Orchid Congress. [No city
of publication given.]
(17) Dressler. R. L. and C. H. Dodson. 1960.
Classification and phytogeny in the Orchidaceae. Anu.
Missouri Bot. Gard. 47:25-68.
(18) Dunsterville, G. C. K., and L. A. Garay. 1959.
Venezuelan Orchids Illustrated. Vol.1. London: Andre
Deutsch. [Also Introduction in Spanish in Vol. 2. 1961.]
(19) Eyde. R. H. 1972. Note on geologic histories of
flowering plants, Brittonia 24:111-116.
(20) Andreanszky, G. 1954. Osnövénytan. Budapest.
Akadémiai Kiado.
10. (21) Garay, L. A. 1960. On the origin of the
Orchidaceae. Bot. Mus. Leaflets Harvard Univ. 19:57-96
[Also in Proc. 3rd World Orchid Conf., London. 1960, pp.
172-196.]
(22) Garay, L. A. [1964.] Evolutionary significance of
geographical distribution of orchids. Pp. 170-187 in Proc.
4th World Orchid Conf,.Singapore, 1963.
(23) Garay, L. A. 1972 On the origin of the Orchidaceae,
II. J. Arnold Arb. 53:202-215.
(24) Godfrey. M. J. 1933. Monograph & Iconograph of
native British Orchidaceae. Cambridge: University Press.
(25) Gothan, W. 1921. H. Potonié’s Lehrbuch der
Paläobotanik. 2. Aufl. Berlin: Gebröder Borntraeger.
(26) Gothan. W. and H. Weyland. 1964. Lehrbuch der
Paläobotanik. 2. Aufl. bv H. Weyland. Berlin: Akademie-
Verlag.
(26a) Harland. W. B., A. G. Smith and B. Wilcock [eds.]
1964. The Phanerozoic time-scale. London: Geological
Society of London. [Issued as a supplement to vol. 120 of
Quart. J. Geol. Soc. London.]
(27) Kirchheimer, F. 1957. Die Laubgewächse der
Braunkohlenzeit. Halle (Saale): Veb Wilhelm Knapp.
(27a) Krackowizer, F. 1953. Orquídeas fosséis. Revista do
Circulo Paulista de Orquidofilos 10(3):36-38.
(28) Krackowizer, F. J. 1964. Orquídeas fosséis. Orquidea
(Rio de Janeiro) 26:39-40.
(29) MacGinitie. II. D. 1953. Fossil plants of the
Florissant beds, Colorado. Carnegie Inst. Washington Pub.
599:i-iii. 1-198.
(30) Machin (ńee Pallot). J. 1971. Plant microfossils
from Tertiary deposits of the Isle of Wight. New. Phytol.
70:851-872.
(31) Massalongo. A. B. 1857. Vorläufige Nachricht
über die neueren paläontologischen Entdeckungen am
Monte Bolca, Neues Jahrb. Mineral., Geognosie 1857:775-
778.
(32) Massalongo. A. B. 1858. Palaeophyta rariora
formationis tertiariae agri Veneti. Atti R. Ist. Veneto Sci.,
Ser. 3, 3:729-793.
(33) Massalongo. A. B. 1859a. Specimen photographicum
animalium quorumdam plantarumque fossilium agri
Veronensis. Veronae: Vincentini-Franchini. [Dual text in
Italian and Latin.]
(34) Massalongo. A. B 1859b. Syllabus plantarum
fossilium hucusque in formationibus tertiariis agri Ve ne ti
detectarum. Veronae: A. Merlo.
(35) Melchior. H. 1964. Reihe Microspermae (Orchidales,
Gynandrae). Pp. 613-625 in H. Melchior [ed.]. A. Engler’s
11. Syllabus der Pflanzenfamilien. 12. Aufl. Bd. 2.
Angiospermen. Berlin-Nikolassee: Gebrüder Borntraeger.
(35a) Menard. H. W. 1 9 7 1 . Science: growth and change.
Cambridge, Mass.: Harvard University Press.
(36) Meschinelli, A., and X. Squinabol. 1893. Flora
tertiaria Ittalica. Patavii: Sumptibus Auctorum Typis
Seminarii.
(37) Naegeli O. 1905. Ueber westliche Florenelemente
in der Nordostschweiz. Ber. Schweiz. Bot. Ges. 15:14-25.
(38) Novak. F. A. 1961. Vyssi rostliny: Tracheophyta.
Praha: Nakladatelství Ceskoslovenské Akademie Véd.
(39) Pijl, L. van der. 1966. Pollination mechanisms in
orchids. Pp. 61-75 in J. G. Hawkcs [ed.]. Reproductive
biology and taxonomy of vascular plants. Oxford: Pergamon
Press.
(40) Pijl, L. van der, and C. H. Dodson. 1966. Orchid flowers:
their pollination and evolution, Coral Cables. Florida:
University of Miami Press.
(41) Potonié. R. 1967. Versuch der Einordnung der
fossilen Sporae dispersae in das phylogenetische System der
Pflanzenfamilien. Forschungsber. Landes Nordrhein-Westfalen Nr.
1761:1-310.
(42) Rolfe. R. A. 1909-12. The evolution of the Orchidaceae.
Orchid Rev. 17:129-132, 193-196. 249-252. 289-292. 353-356;
18:33-36, 97-99. 129-132, 162-166, 289-294. 321-325; 19:68-69.
289-292: 20:204-207, 225-228. 260-264. [General discussion
in 20:225-228, 260-264.]
(43) Schimper, W. P.. and A. Schenk. 1879-90.
Palaeophytologie. Abt. 2 in K. A. Zittel [ed.], Handbuch der
Palaeontologie. Münchcn: R. Oldenbourg. [Also the 1891
translation into French by C. Barrois et al.:
Paleophytologie. Pt. 2 in K. A. Zittel [ed.]. Traité de
paléontologie.]
(44) Schultcs. R. E. 1960. Native orchids of Trinidad and
Tobago. New York: Pergamon Press.
(45) Schultes, R. E. 1966. Orchid [in part]. Pp. 1041-1043
in Encyclopaedia Brittanica. Vol. 16. Chicago: Encyclopaedia
Brittanica. [Also in subsequent editions.]
(46) Schultes. R. E., and A. S. Pease. 1963. Generic
names of orchids: their origin and meaning. New York:
Academic Press.
(47) Sernander, R. 1894. Studier öfver den Gotländska
vegetationens utvecklingshistoria, Ph.D. Thesis, Universitet i
Uppsala. 1 1 2pp. [Privately printed.]
(48) Stebbins, G. L. Jr. 1950. Variation and evolution
in plants. New York: Columbia University Press.
(49) Straus, A. 1954. Beiträge zur Pliocänflora von
Willershausen. IV. Die Monocotyledonen. Palaeontographica
96B:1-11
12. (50) Straus, A. 1969. Beiträge zur Kenntnis der
Pliozänflora von Willershausen (VII). Die Angiospermen-
Früchte und -Samen. Argumenta Palaeobotannica 3:163
197.
(51) Thurmann, J. [1833.] Essai sur les soulèvemens
Jurassiques du Porrentruy, avec une description
géognostique des terrains secondaires de ce pays, et des
considérations générales sur les chaines du Jura. Mém. Soc.
Hist. Nat. Strasbourg 1 (livre. 2, article "L"):l-84.
(52) Vent, W. 1965. Neue Pflanzenfunde aus den
interglazialen Ilmtaltiavertinen von Weimar-Ehringsdorf.
Geologie 14:198-205.
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