Genetic variation inOrchis papilionacea (Orchidaceae) from the Central Mediterranean region: Taxonomic inferences at the intraspecific level

The genetic differentiation ofOrchis papilionacea from Italy, Corsica, Sardinia, Sicily, and Greece was analyzed by isozyme studies. No significant differences at any of the 28 loci tested were observed between samples of the putative subspeciespapilionacea from Italy,grandiflora from Sicily andheroica from Greece, or by comparing sympatricpapilionacea-like andgrandiflora-like subsamples from Sardinia and Corsica. The genetic relationships found among the populations studied reflect more their geographic origin than their taxonomic assignment;papilionacea, grandiflora, andheroica are, therefore, at least in the study area, not to be considered as subspecies, but as simple morphs, controlled by few genes (possibly two) with Mendelian inheritance. The genetic divergence observed among the samples studied is very low and consistent with that of geographic populations of a single cohesive gene pool, linked by a high gene flow (Nm = 5.9).     

Genetic variation and natural hybridization betweenOrchis laxiflora andOrchis palustris (Orchidaceae)

Genetic divergence between population samples ofOrchis laxiflora and ofO. palustris from various European locations was studied by electrophoretic analysis of 25 enzyme loci. An average genetic distance of D_Nei = 1.24 was found between the two taxa, with 12 out of 25 loci showing alternative alleles (diagnostic loci). Genetic heterogeneity was observed within bothO. laxiflora andO. palustris, when northern and southeastern populations were compared, being lower in the former taxon (D = 0.06), than in the latter (D = 0.16). Karyologically, 2n = 36 was found for bothO. laxiflora andO. palustris. O. laxiflora andO. palustris produce hybrids, described asO. ×intermedia. Genotype analysis of several sympatric samples showed the presence of hybrid zones, including F₁ hybrids and, in low proportions, recombinant classes, putatively assigned to F_n and backcrosses, as well as a few introgressed individuals of both taxa. These data indicate that hybrids are only partially fertile, with a very limited mixing up of the two parental gene pools; this is also shown by the lack of significant lowering of genetic distances when sympatric and allopatric heterospecific samples are compared. Accordingly,O. laxiflora andO. palustris form a syngameon; nevertheless they can be considered as good taxonomic species, with virtually distinct gene pools, which evolve independently. The genetic variability inO. laxiflora andO. palustris is remarkably low ( _e = 0.05 and _e = 0.02, respectively). In particular, nearly complete absence of polymorphic loci was found inO. palustris from northcentral Europe. Two hypotheses are considered to explain the low genetic variability of this endangered species.     

New and noteworthyHabenaria spp. (Orchidaceae) from New Guinea and adjacent islands

5 new taxa ofHabenaria, namelyH. bougainvillae, H. elongata R. Br. var.leptophylla, H. ensigera, H. rechingeri andH. trichoglossa, are described and illustrated, with reference to affinities to related Australian and Indo-malayan species. The occurrence in New Guinea of severalHabenaria spp. typical for a savanna-like vegetation, led to look more thoroughly at these taxa:H. elongata R. Br. andH. ochroleuca R. Br., considered so far to be endemic in Northern Australia, andH. khasiana Hook. f., hitherto only known from southeastern Asia.Studies in the subtribeHabenariinae Bentham (Orchidaceae), 2.—Part 1: Candollea34, 357 (1979).Dedicated to Hofrat Prof. DrKarl Heinz Rechinger on the occasion of his 80th birthday. — On April 30, in the year 1927, the author and his brotherOtto Renz metKarl Heinz Rechinger on a small steam-boat in a stormy Aegaen Sea, travelling from Piraeus to the Northern Sporades Islands:Karl Heinz with destination to Chelidromia, the author andO. Renz to Skopelos. By this lucky chance a lasting friendship began.     

Orchis prisca (Orchidaceae), eine neue Art aus Kreta

Orchis prisca Hautzinger is described as a new diploid species from Crete, related toO. patens andO. spitzelii.

     

A new species ofLiparis (Orchidaceae) from India

Liparis indiraii spec. nova from India is close toL. alata A. Rich. andL. atropurpurea Lindl.     

Labellum micromorphology in theOphrys bertolonii agg. and some related taxa (Orchidaceae)

Micromorphology and distribution of trichomes in six taxa of theOphrys bertolonii aggregate (O. bertolonii, O. bertoloniiformis, O. benacensis, O. aurelia, O. drumana, O. catalaunica) are described. A fairly good homogeneity between all the taxa, with a moderate degree of variability even within the same taxon, has been observed. Comparison of these characters with those ofO. promontorii andO. garganica corroborates the inclusion of the former species into theO. sphegodes aggregate. Trichome analysis of a hybrid is exemplified byO. ×chiesesica (O. drumana ×O. fuciflora).     

Molecular (RAPD) analysis on Italian taxa of theOphrys bertolonii aggregate (Orchidaceae)

The RAPD technique has been used for analyzing the genetic material of seven Italian populations of theOphrys bertolonii aggregate (Orchidaceae). For comparison the related speciesO. sphegodes andO. fuciflora have also been analyzed. A high genetic variability has been observed within the same populations, and on the whole onlyO. bertolonii can be safely differentiated from the other taxa of the aggregate, which are undistinguishable with this method.     

Effect of the breeding system on the genetic structure in threeCephalanthera spp. (Orchidaceae)

The genetic variation of seven enzymes for a total of nine loci was investigated in three species of terrestrial orchids of the genusCephalanthera:C. longifolia, C. rubra, andC. damasonium. These species are characterized by presenting different breeding types: outbreeding , outbreeding with facultative vegetative reproduction, and inbreeding, respectively. Electrophoretic evidence points to a difference in the behaviour of each of the three species which seems strictly related to the breeding type. On the basis of our resultsC. longifolia behaves as a normal outbreeder, whileC. rubra presents the influence of vegetative reproduction in some populations and not in others.C. damasonium shows a total lack of both among and within populations genetic variation, which is most probably due to the autogamic breeding type.     

Hybriden und hybridogene Sippen ausOphrys bertolonii undO. atrata (Orchidaceae)

Flower polymorphism in 15 ItalianOphrys populations (N = 282) was analysed in detail. Statistical and graphical evaluation of data demonstrates morphological relationships and amount of hybrid character coherence.O. bertolonii s. str. andO. atrata are stable parental taxa, but occasionally form hybrids and hybrid swarms. Much evidence suggests that it was through such homogamic hybridization, involving these and other species ofOphrys, that the stabilized taxaO. bertoloniiformis andO. promontorii (ecologically different, but sympatric with the parents on Gargano), andO. benacensis (geographically separated from the parents in the Insubric region) originated. These differentiation-hybridization cycles are linked to the break-down and new establishment of incomplete prezygotic crossing barriers (e.g. different flower biology, flowering time, habitat preference).

     

Karyological differentiation and speciation in C. MediterraneanAnacamptis (Orchidaceae)

Anacamptis pyramidalis is a variable and wide-spread European-Mediterranean taxon. Beside a dominant cytotype with 2n = 36 it includes cytotypes with 2n = 54 and 63 in northern Tuscany (and the Eastern Pyrenees) and one with 2n = 72 on Malta. In contrast,A. urvilleana, formerly often misidentified and included inA. pyramidalis, is a monomorphic and distinct species, endemic to the Maltese Islands. It has 2n = 36, can be clearly separated by morphological and anatomical features and is isolated from partly sympatric populations ofA. pyramidalis with 2n = 72 by differences in chromosome number, flowering time and habitat preference.     

Taxonomical investigations onHelleborus viridis s. l. (Ranunculaceae) in Northern Italy

The taxon commonly namedHelleborus viridis in Lombardy (NW. Italy) differs from both, subsp.viridis and subsp.occidentalis, and is shown to fall within the variation range ofH. odorus subsp.laxus which has been reported so far for NE. Italy only. TrueH. viridis within Italy grows only in the Maritime Alps.     

Biometrical analysis on populations ofOrchis israelitica,O. caspia,and their hybrids (Orchidaceae)

The population variability ofOrchis israelitica, O. caspia, and their intermediates, from two localities in Israel, was analyzed and illustrated by scatter diagram and hybrid index. It is suggested that the hybrids are a result of introgression and are closer toO. caspia. Aspects of isolating barriers between these two species are discussed.     

Insect pollination and floral mechanisms in South African species ofSatyrium (Orchidaceae)

The morphologically diverse flowers in the genusSatyrium reflect adaptations to a wide range of pollinators. Several recently discovered pollination systems inSatyrium are described and illustrated here; these include pollination by solitary bees, carrion flies, butterflies and moths. Two basic types of floral mechanism are recognised inSatyrium: (1) Species pollinated by lepidoptera and birds have long floral spurs and plate-like viscidia seated in lateral rostellum notches; these viscidia become attached to the proboscis or bill of the pollinator. (2) Species pollinated by flies and bees have relatively short floral spurs and globose viscidia seated in terminal rostellum notches; these viscidia become attached to the face, thorax or eyes of the pollinator.     

Seed morphology in Southern AfricanOrchidoideae (Orchidaceae)

The seed morphology of 151 species of Southern AfricanOrchidoideae (Orchideae andDiseae; sensuDressler 1981) was studied by means of scanning electron microscopy. Two different seed types were found. (1) In the majority of species the seeds are minute and fusiform. The seed coat is made up of comparatively few concave and elongate testa cells with straight or slightly undulate and generally unthickened anticlinal cell walls. The seed type was here termed Satyrium-type. While most species are very similar in the ornamentation of the periclinal walls of their seed coat, considerable variation was found inHolothrix where two distinct groups can be recognized in this respect. (2) A remarkably different seed type was observed inDisa uniflora and three apparently closely related species (Disa uniflora-type), where large balloon-like seeds occur. Their seed coat consists of convex cells with undulate anticlinal walls. It is suggested that this seed type is a derived condition and has evolved in adaptation to the specialized habitat alongside streams. The possibility of hydrochory in these four species is briefly discussed.     

Morphological and molecular characterization of a natural hybrid betweenOrchis laxiflora andO. morio (Orchidaceae)

A putative natural hybrid betweenOrchis laxiflora andO. morio (Orchidaceae) from southern Italy, formerly known asO. alata, was characterized both on morphological and molecular grounds in order to confirm its hybrid status and to trace its maternal lineage. The morphological characters of the putative hybrid showed intermediacy between those of the parent species, and restriction fragment length polymorphism (RFLP) analysis of a region of the nuclear ribosomal DNA confirmed its hybrid origin. Chloroplast DNA RFLP analysis indicated thatO. morio provided the maternal genome.     

The embryology ofEpipogium roseum (Orchidaceae)

Development of pollen and female gametophyte inEpipogium roseum (D. Don)Lindl. has been investigated. The embryo sac conforms to the Apinagia type. The taxonomic position ofEpipogium within the family is discussed.     

Characterization of interspecific hybrids betweenOrchis mascula andO. pallens (Orchidaceae) by enzyme electrophoresis

The European orchidsOrchis mascula, O. pallens and their hybrids have been analysed by enzyme electrophoresis on starch gels. The two species differ in the electrophoretic mobilities of four out of eight enzymes tested. Three enzymes, phosphoglucomutase, phosphoglucoisomerase and malic enzyme exhibit typical heterozygote patterns in the hybrid plants demonstrating the presence of both differing parental alleles. Thus, species identification is easy by the electrophoretic analysis of a low number of enzyme loci, and hybrids are detectable even if morphological characters fail.     

Pollination ofOphrys (Orchidaceae) in Cyprus

In the southern part of Cyprus the pollinator —Ophrys (Orchidaceae) relationships and its specifity have been investigated from the end of February until the middle of March 1986. 12Ophrys spp. were found. To date, only a single pollinator reference has been reported from this island. We found the following pollinators:Melecta tuberculata (Ophrys kotschyi),Eucera dimidiata (Ophrys flavomarginata),Eucera gaullei (Ophrys umbilicata),Eucera paulusi (Ophrys bornmuelleri),Anthophora erschowi (Ophrys elegans),Andrena torda (Ophrys sicula =O. lutea subsp.minor),Andrena cinereophila (Ophrys fusca, small-flowered),Andrena flavipes (Ophrys israelitica),Andrena morio (Ophrys iricolor andOphrys transhyrcana),Andrena bimaculata (Ophrys sphegodes aggr., probably formerly confused withO. transhyrcana). Most interestingly, it could be verified thatO. flavomarginata/O. umbilicata, O. bornmuelleri/O. levantina andO. transhyrcana/O. sphegodes aggr. (possiblyO. sintenisii) are different biospecies. This is a result of genetic isolation due to varying pollinators, and of differences in flower morphology.     

Observations of the floral biology ofPrasophyllum odoratum (Orchidaceae,Spiranthoideae)

Prasophyllum odoratum is a vernal, nectariferous, terrestrial orchid that flowers profusely six to eight months following cyclical fires that disrupt sclerophyll woodlands. The morphology of the column and pollinarium is indicative of taxa placed within the subfam.Spiranthoideae. The orientation of the pollinaria to the stigma appears to prevent mechanical self-pollination. Both cross- and self-pollination appear to be effected by insects that forage within the brightly-colored, scented, non-resupinate flowers. Ants and drosophilid flies remove nectar, but do not appear to transport pollinaria between flowers. The primary pollinators are polytrophic flies in the fam.Syrphidae and opportunistic male bees in the genusLeioproctus (Colletidae). Approximately 52% of the flowers on a raceme set seed. The comparatively short floral tube ofP. odoratum reflects the dependence of this species on short-tongued insects to effect successful dispersal of pollinaria.     

Gene flow inAgrostis tenuis (Poaceae)

The copper tolerance of both adult plants and their seedlings, ofAgrostis tenuis from sites within and outside, but neighbouring the Parys Mountain mine (North Wales) were studied. Intensive sampling was carried out along a line starting from the mine boundaries to a distance of five miles away in the direction of the prevailing wind, and of two miles in an upwind direction. The test have shown that mine populations are very tolerant. In outside populations on soils with reduced of very low copper content the mean tolerance level of the seedlings is considerably higher than that of corresponding adult plants, while both show a gradual decrease in tolerance with distance from the mine. The gene flow moves in the direction of the prevailing wind transfering tolerant characters from the mine to the normal populations. The selective pressures on the toxic soil of the mine are quite strong and permit ± tolerant plants only, while on normal soils these pressures are not so severe, so that populations may be rather heterogenous regarding their tolerance towards copper.