Fossils attributed to_the_orchidaceae


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Fossils attributed to_the_orchidaceae

  1. 1. Fossils Attributed to the Orchidaceae RUDOLF SCHMID AND MARVIN J. SCHMID1INVESTIGATORS INTERESTED IN the evolutionary history of a familydesire to have information from the fossil record to provide(hopefully) unequivocal evidence for the early history of thatfamily. Unfortunately for orchidologists, the known fossil recordof the Orchidaceae is extremely meager. We decided to summarizewhat is known of the fossil record of orchids (a) because there areno accounts available other than the rather superficial ones byDarrah (15) and Krackowizer (27a, 28) , (b) because there are numberof misconceptions in the literature that should be corrected,and, most importantly, (c) because a reasonably complete list offossils attributed to the Orchidaceae could be prepared since we hadaccess to the Compendium Index of Paleobotany (see 3, 19 foraccounts of its coverage) and to libraries with extensive holdingsin rather obscure publications.Most persons seem to favor a relatively great age for theOrchidaceae (e.g., 1, 5, 6, 12, M, 15, IS, 21-23, 48), but relativelyfew have ventured a specific time and/or place of origin. Garay (21-23), following Stebbins (48, pp. 501-502), postulates an origin inthe early Cretaceous- and in addition proposes Malaysia as themost likely cradle of orchidhood. Leon Croizat (pers. comm.,1972) believes that the orchids arose "surely not later than theearliest Cretaceous. Brieger (5, 6) favors the early Tertiary and the"united Asiatic-American" tropics (6, p. 329, specific area notindicated). In contrast, some authors, notably Schultes, believethat the orchids may be "a comparatively young group" (44, p. 1;45, p. 1043). While there is some dispute as to the exact time oforigin of the family, nearly all workers (e.g., 5, 16, 17, 21. 40, 44)seem to agree that currently, and in the immediate past, theOrchidaceae are in a very active period of evolution.Most workers have indicated either that there is no fossil record forthe Orchidaceae (e.g., 1, 6, 10, 12, 13, 20, 24) or that there areonly 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 thefossil record of the Orchidaceae chiefly or only on knowledge of thevery dubiously orchidaceous Protorchis monorchis and Palaeorchisrhizoma described by Massalongo (31-34) from the Eocene ofItaly. 4 Nevertheless, a number of other fossils have also been attributed tothe Orchidaceae, most significantly Straus (49, 50) three species ofputative orchid fruits (Orchidacites) from the Pliocene of Germany. Withthe exception of Gothan and Weyland (26), Kirchheimer (27), and Melchior (35),however, most recent workers seem unaware of Straus finds. These and othertaxa will be discussed in detail below.
  2. 2. Table 1. Geologic time scale (pre-Mesozoic omitted). (After Hartland, 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 54Cenozoic Tertiary Paleocene 65 Cretaceous 136 Jurassic 190Mesozoic 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 Potonies (41) recent compendium of fossil pollen and spores. Although Chandlers (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. 3. she suggested (8, p. 29) that "possibly search for pollen among the finersediments 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, bothcited in 9, the latter published as 30) , however, has thus far failed tosubstantiate this prediction.As recently discussed by Eyde (19), there are several paths into thepaleobotanical literature. We checked a variety of sources for records oforchidaceous fossils, most importantly the index by Andrews (3, includingunpublished cards for additions since 19(>5) and the United States GeologicalSurveys Compendium Index of Paleontology, an unpublished file available forconsultation only in the Natural History Building, Room W-300, of theSmithsonian Institution, Washington, D. C. (see 3, 19) . We checked theCompendium Index for most of the temperate genera listed in Schultes andPease (46). Most tropical genera, however, were not sought in theCompendium Index due to the minuscule yield that could only result fromsuch a mountain of effort. As noted above, tropical plants are unlikelycandidates for fossilization. In addition, most tropical orchids are endemicsthat presumably evolved during the Quaternary, and hence any fossils of themwould be unlikely to be encountered by paleobotanists, most of whom haveworked (until very recently, at least) in temperate areas. Finally, anyorchidaceous fossils of the pre-Quaternary tropical floras of presently temperateareas would probably be given generic names not based on living taxa. 5 REPORTS OF ORCHIDACEOUS FOSSILSThree extinct genera (Palaeorchis, Protorchis and Orchidacites) have beendesignated as orchidaceous or protorchidaceous. At least one other fossil taxon,Antholithes pediloides, has been regarded as an orchid. In addition, fossilremains from the Quaternary have been attributed to a number of extant,north temperate orchid taxa. Purists who restrict "fossils" to pie-Quaternaryremains and therefore regard Pleistocene finds as "subfossils" may object to theinclusion of plant remains from the Quaternary in the following enumera-tion: Jurassic The Compendium Index of Paleobotany, citing Thurmann (51) , lists thefollowing extant species as occurring in the Jurassic strata at Porrentruy,France: Ophrys myodes Jacq., Orchis morio L., O. pyramidalls I,., Satyriumviride L., and Serapias rubra L. This is incorrect. Thurmann did indeed listthese species, but only as part of the modern vegetation of this region. EoceneProtorchis monorchis Massalongo (31-33) and Palaeorchis rhizoma (.Massalongo)Massalongo (32) (= Protorchis rhizoma Massalongo, 31): These species representthe first described and also the geologically oldest fossils that might possiblyrepresent orchids. In 1857 Massalongo (31) listed, without benefit of descriptionor illustration (hence nomina nuda) , the new generic name Protorchis, withtwo new species P. monorchis and P. rhizoma based on specimens from thecalcareous Eocene deposits at Monte Bolca, Italy. Massalongo had onlyfour specimens at his disposal — three of the former species, one of the latter(33, 34). In 1858 Massalongo (32) validly published Protorchis monorchis andalso the new combination Palaeorchis rhyzoma (the specific epithet is anorthographic error) based on Protorchis rhizoma. The next year a morecomplete description and also a photograph (see Fig. 1) of Protorchis monorchiswere 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 1854reference is obviously unpublished, the nomina nuda in the 1857 report (31)thus represent the actual first (though taxonomically invalid) publication of
  4. 4. the names involved.Although Massalongo (31) initially listed his new species under theOrchidaceae, he subsequently (32-34) very carefully indicated the tentativelyorchidaceous 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 unableto find in the extant flora counterparts of his fossils. Massalongo (32, 33) noteda resemblance of both his fossil species to the Araceae, which he apparentlyregarded as being rather close to the Orchidaceae (32). A superficial likenessbetween Palaeorchis rhizoma and the fossil alga Delesserites was rejected whenhe decided on the affinities of the former (32). After additional concern thatPalaeorchis rhizoma might be butomaceous, Massalongo (32) finally decidedto retain this species in his Protorchidaceae. This discussion illustratesthe difficulty Massalongo had in assigning his fossils to an extant plantgroup. 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 regardedhis fossils as orchids.
  5. 5. According to Massalongo (32, descriptive terminology below is his) , theProtorchidaceae are next to the orchids and the aroids and consist of smallherbs with tubers or rhizomes bearing lateral fibrous roots and several veryslender, cuneate-obovate or spathulate leaves with entire margins and finemidribs. Misstatements to the contrary (15, 25, 26, 28, 43), both species do notpossess tubers. Protorchis monorchis (FIGURE 1) has a round, solitary tuberwhereas Palaeorchis rhizoma (never illustrated by Massalongo) differs chieflyin having a perpendicularly cylindrical rhizome covered with circular,papillate leaf scars (32). The two species also differ somewhat in havingspathulate 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 rathera rounded rhizome (FIGURE 1). In the same publication he (33) also added the
  6. 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 mmwide.11 Although Massalongo (34, p. 133) finally indicated that specimens ofboth this species and Palaeorchis rhizoma are seedlings, there is no mention inhis previous descriptions (32, 33) of the probable developmental age of thesefossils.Most workers, usually referring only to Protorchis monorchis, havesubsequently concluded that Massalongos fossils are not truly representativeof the Orchidaceae (e.g., 15, 18, 21, 25, 26, 35, 39, 40, 42). Schimper and Schenk(43) , however, accepted Massalongos finds as orchidaceous, and van der Pijl(39, 40) apparently seems tempted to accept Protorchis monorchis as validlyorchidaceous, no doubt because its Eocene date ties in with his understandingof the evolution of the bees. Meschinelli and Squinabol (3i) included both ofMassalongos fossil species under the Protorchidaceae in the order Micro-spermae (= Orchidales), but these authors noted that Palaeorchis rhizoma isprobably a member of the Butomaceae. Krackowizer (28) 7 accepted the views ofMeschinelli and Squinabol (36) except that he regarded Protorchis monorchisas a true orchid rather than as a protorchid. Admitting that both ofMassalongos fossils are doubtfully orchidaceous, Leslie A. Garay (pers. comm.,1972) nevertheless maintains that of all the fossils attributed to theOrchidaceae, Protorchis monorchis is perhaps the most likely candidate forinclusion in the family, largely because of its similarity to Orchis pallens L.In conclusion, the orchidaceous nature of Massalongos fossils is clearly veryquestionable. As has already been suggested (Chester A. Arnold, pers. comm.,1967; 15, 18), perhaps the most charitable tiling that can be said about theaffinity of Protorchis and Palaeorchis is that they are monocotyledonous. OligoceneAntholithes pediloides Cockerell (1 1): T. D. A. Cockerell, the prolificdescriber of fossils from the western United States,8 in 1915 delineated fromthe Lower Oligocene (the age according to MacGinitie, 29; incorrectlyregarded as Miocene by Cockerell, I I ) beds at Florissant, Colorado, a newspecies in the fossil artificial (or form) genus Antholithes. Cockerell attributedthe fossil (FIGURE 9), A. pediloides, to the Orchidaceae because of its markedresemblance to the lip of Cypripedium, and he also presumed that the severalsmall "subhyaline" spots scattered over the surface might represent the workof some insect. Other than the suggestive outline of the fossil, however, the lackof significant detail makes Cockerells determination extremely doubtful. Inhis classic flora of the Florissant beds, MacGinitie (29) reached the sameconclusion and disposed of A. pediloides among "species of somewhat doubtfultaxonomic value" (p. 159) under incertae sedis. MioceneDarrah (15) briefly discussed, and then discounted as truly orchidaceous, afossil stem (apparently unnamed) from the Miocene of Hungary that had beendescribed by a Robert Brown (there were several Robert Browns). SinceDarrah provided no references in his note, and since alter considerablesearching we have been unable to locate any additional informationconcerning this fossil, we can only quote Darrah (15, p. 149) fully: "A third form [besides Massalongos 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. 7. PlioceneOrchidacites orchidioides Straus (49), O. wegelei Straus (49), and O.cypripedioides Straus (50): In 1954 Straus (49) described from the UpperPliocene of Willershausen, Germany, two species of fruits, Orchidacitesorchidioides and O. wegelei which he assigned to the Orchidaceae. The twospecies, especially the former (as suggested by i t s name), were thought toresemble various species of Orchis (49). More recently, Straus (50) providedfor Orchidacites a generic diagnosis, which had been omitted from the 1954report, and described a third species, O. cypripedioides, with fruits regardedas similar to those of Cypripedium. These taxa are illustrated in FIGURES2 to 8, reproduced from Straus more recent paper (50). Orchidacitesis a form genus proposed for fossil fruits comparable to the capsulesof various extant orchid genera (50). According to Straus (50), thefossil capsules, 1.5 to 2.5 cm long, are ellipsoidal or narrowly ellipsoidal andhave several longitudinal striae (FIGURES 2-8); the remnants of a corolla oftenoccur at the fruit apex (FIGURES 2-4).Straus (50, also pers. comm., 1972) believes that the fossil fruits ofOrchidacites came from epiphytes growing on rotting branches that eventuallywere blown into the sediments by wind, and, as a consequence, he hasspeculated (50, pers. comm., 1972) that many of the present-day orchids (e.g.Limodorum, Neottia, Corallorrhiza, and Cypripedium) were primitivelyepiphytic and now are terrestrial "secondary relicts." This view, of course, isdissonant with the conventional one that the terrestrial habit is ancestral andthe epiphytic derived (e.g., 5, 6, 16, 17, 21-23, 39, 42).The Straus fossils have received little comment from either orchidologists orpaleobotanists. Melchior (35) and Gothan and Weyland (26) accepted thefossils as unmistakably orchidaceous. Kirchheimer (27, p. 650), however,remained skeptical, believing that the inferior, wing like, ribbed gynoeciumwith a distinct styloid process evokes resemblances to young fruits of Halesia,Pterostyrax and other Styracaceae (a completely unrelated family in thedicotyledons). Straus (pers. comm., 1972), in counterargument, however,believes that the fruits he described are truly orchidaceous since fruits of theStyracaceae never show floral remains whereas fruits of the Orchidaceae oftendo.On examining the photographs reproduced herein ( FIGURES 2-8), Garay(pers. comm., 1972) is also disinclined to accept Straus fossils as orchidaceousbecause of the curious 3-pronged floral remnants (interpreted by Garay asa column) ( FIGURES 2-4) and because of the apparently excessive number ofribs ( 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 isless certain in excluding Orchidacites cypripedioides (FIGURES 5-8) from theorchids since the fossil "looks rather like a Cattleya fruit."In defense of Straus, we should note that a 3-pronged calyx of fused sepalsoccurs 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 beapparent since these may be variously secondarily divided (e.g., Trichopiliasuavis Lindl. et Paxton). Unfortunately, Straus (50) hurts his own cause byinterpreting the floral remnants (FIGURES 2-4) as a corolla, but it is perhapsmore likely that they represent a calyx. QuaternaryQuaternary orchid fossils are included here for completeness, although theyare unimportant from the viewpoint of our understanding of the origin andmost of the subsequent evolution of the family. The names of at least 20 extantspecies of orchids are listed in the Compendium Index of Paleobotany and are
  8. 8. attributed to both the Pleistocene and Holocene (= Recent or Postglacial) ofthe Quaternary. Most of these listings were compiled around the turn of thecentury, when the Compendium Index included casual, incidental referencesto fossils - a practice long discontinued ( 1 9 ). Unfortunately, a number ofthese listings are not applicable because the original works discuss the variousorchid species as components of the contemporary flora and not as fossils. Thisis the case with reports of Goodyera repens (L.) R. Br. from the Quaternary ofDenmark, Himantoglossum hircinum (L.) Sprengel and Ophrys araniferaHuds. from the Postglacial of Switzerland, and Malaxis paludosa (L.) Sw. fromthe Holocene of Germany, which the Compendium Index attributes toAnderson (2), Naegeli (37, as cited in 7), and Becker (4), respectively.The Compendium Index also attributes the following extant orchid taxa toSernanders (47) extensive work on the Quaternary (Wiirm Glacial andPostglacial) 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, Gymnadeniaconopsea (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 interms of a phytosociological survey of the modern bog vegetation of Gotland.The bogs Sernander studied did indeed contain identifiable fossils, but noneof these were orchids.To our knowledge, there is only one report of a Quaternary fossil attributed tothe Orchidaceae. In 1965 Vent (52, p. 200) described leaf and fruitimpressions from the Riss-Wurm Interglacial of Weimar-Ehringsdorf, Germa-ny, and assigned these to "cf. Epipactis palustris (Mill.) Crantz" in theOrchidaceae. Garay (pers. comm., 1972) , however, discounted the orchidaceousnature of these fossils after examining Vents photographs (FIGURE 10) . SUMMARYFossils dating from the Eocene to the Quaternary have been attributed to theOrchidaceae, but objections have been raised against the orchidaceous natureof all of these fossils. The most likely orchid fossils, nevertheless, remainMassalongos famous fossils from the Eocene of Italy — Protorchis monorchisand Palaeorchis rhizoma — and especially Straus recent finds from thePliocene of Germany Orchidacites orchidioides, O. wegelei and O.cypripedioides. In conclusion, then, the Orchidaceae have no positive fossilrecord and in this sense present a striking parallel to two well-known gods ofmythology: Athena, who sprang fully grown and fully armored from the headof Zeus; and the Aztec Huitzilopochtli, who was borne fully grown and fullyarmored from Coatlicue.Acknowledgements: This study was carried out while the senior author was therecipient of a Smithsonian Institution postdoctoral fellowship. We thank NorrisH. 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. 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 NorthAmerica. 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. 10. (21) Garay, L. A. 1960. On the origin of theOrchidaceae. 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 ofgeographical 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 ofnative British Orchidaceae. Cambridge: University Press.(25) Gothan, W. 1921. H. Potonié’s Lehrbuch derPaläobotanik. 2. Aufl. Berlin: Gebröder Borntraeger.(26) Gothan. W. and H. Weyland. 1964. Lehrbuch derPaläobotanik. 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 derBraunkohlenzeit. 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 theFlorissant beds, Colorado. Carnegie Inst. Washington Pub.599:i-iii. 1-198.(30) Machin (ńee Pallot). J. 1971. Plant microfossilsfrom Tertiary deposits of the Isle of Wight. New. Phytol.70:851-872.(31) Massalongo. A. B. 1857. Vorläufige Nachrichtüber die neueren paläontologischen Entdeckungen amMonte Bolca, Neues Jahrb. Mineral., Geognosie 1857:775-778.(32) Massalongo. A. B. 1858. Palaeophyta rarioraformationis 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 plantarumfossilium hucusque in formationibus tertiariis agri Ve ne tidetectarum. Veronae: A. Merlo.(35) Melchior. H. 1964. Reihe Microspermae (Orchidales,Gynandrae). Pp. 613-625 in H. Melchior [ed.]. A. Engler’s
  11. 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. Floratertiaria Ittalica. Patavii: Sumptibus Auctorum TypisSeminarii.(37) Naegeli O. 1905. Ueber westliche Florenelementein 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 inorchids. Pp. 61-75 in J. G. Hawkcs [ed.]. Reproductivebiology and taxonomy of vascular plants. Oxford: PergamonPress.(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 derfossilen Sporae dispersae in das phylogenetische System derPflanzenfamilien. 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 discussionin 20:225-228, 260-264.](43) Schimper, W. P.. and A. Schenk. 1879-90.Palaeophytologie. Abt. 2 in K. A. Zittel [ed.], Handbuch derPalaeontologie. Münchcn: R. Oldenbourg. [Also the 1891translation into French by C. Barrois et al.:Paleophytologie. Pt. 2 in K. A. Zittel [ed.]. Traité depaléontologie.](44) Schultcs. R. E. 1960. Native orchids of Trinidad andTobago. New York: Pergamon Press.(45) Schultes, R. E. 1966. Orchid [in part]. Pp. 1041-1043in Encyclopaedia Brittanica. Vol. 16. Chicago: EncyclopaediaBrittanica. [Also in subsequent editions.](46) Schultes. R. E., and A. S. Pease. 1963. Genericnames of orchids: their origin and meaning. New York:Academic Press.(47) Sernander, R. 1894. Studier öfver den Gotländskavegetationens utvecklingshistoria, Ph.D. Thesis, Universitet iUppsala. 1 1 2pp. [Privately printed.](48) Stebbins, G. L. Jr. 1950. Variation and evolutionin plants. New York: Columbia University Press.(49) Straus, A. 1954. Beiträge zur Pliocänflora vonWillershausen. IV. Die Monocotyledonen. Palaeontographica96B:1-11
  12. 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.