Critical Reexamination of Palynological Characters Used to Delimit Asclepiadaceae in Comparison to the Molecular Phylogeny Obtained from PlastidmatK Sequences

The family Asclepiadaceae (Dicotyledones) was created by Brown in 1810 by splitting in two the family Apocynaceae of Jussieu established in 1789. The morphological characters used to make this distinction were mainly palynological, such as presence of tetrads or pollinia and number and orientation of pollinia. Those characters, still used in higher taxonomic delimitation (families, subfamilies, and tribes), are here critically reexamined and compared to a molecular phylogeny obtained with one of the more variable plastid genes (matK) of 46 species in the order Gentianales. In this molecular phylogeny, Asclepiadaceae form a monophyletic group derived from within Apocynaceae. Each of the subfamilies of Asclepiadaceae is monophyletic and based on reliable palynological characters, but palynological characters are not useful to delimit tribes of the subfamily Asclepiadoideae. Based on the molecular data, these tribes have undergone parallelisms in several reproductive traits.     

Taxonomic separation ofKengyilia (Poaceae: Triticeae) in relation to nearest relatedRoegneria,Elymus, andAgropyron,based on some morphological characters

Based on 100 species representative of the four genera, we scored 290 herbarium specimens for a number of morphological characters. The data were subjected to canonical discriminant analysis using characters different from those in the identification key to these genera byBaum, Yen, andYang (1991). These characters collectively support the four groupsAgropyron, Kengyilia, Roegneria, andElymus as previously defined. The four groups are also supported by the linear discriminant function with an overall rate of 83% correct classification. Length of lemma awn was found to be an additional diagnostic character asAgropyron andKengyilia have lemma awns shorter than 5 mm, whereasRoegneria andElymus have longer lemma awns with very few exceptions. Length of glume awns is also a useful supplementary generic diagnostic.Agropyron andElymus have glume awns, whereas the majority of species ofKengyilia and more than half of the species ofRoegneria lack them. If a glume awn is present it is usually not longer than 1 mm.     

Ontogeny of the translator inAsclepiadaceae s.str.

The ontogeny of the translator is analysed inFockea edulis, Pachycarpus dealbatus, andCalotropis procera. The three species show a similar basic pattern in the construction of the corpusculum. Each side wall consists of two originally separate flanks. In the primitive state (Fockea), these flanks remain separate throughout their development, only the two inner flanks fuse along their base. In the derived state, the two flanks on each side fuse to form solid side walls, and the corpusculum develops a floor by additional secretion. The primitive state of divided flanks is recapitulated in early ontogeny. InFockea, the pollinia are attached apically and dorsally to the outer flanks by means of unmoulded adhesive material; in more advanced translators, caudicles are inserted as new elements between the outer flanks and the pollinia. The caudicles are attached to the lower part of the corpusculum. Within the four tribes of the family, many species have retained parts of the primitive structure in their corpuscula. Flanks divided in the lower part of the corpusculum and caudicles attached dorsally to the outer flanks seem to be common inMarsdenieae andStapelieae. InAsclepiadeae andGonolobeae the side walls are solid throughout the length of the corpusculum. — The question of cellular mechanisms underlying the formation of the translator is discussed. In all probability, the main factor responsible for the complex structure of the corpusculum is a differential secretory activity of the glandular field. This, in turn, points to differential genetic activity as a regulating factor of the ontogeny of the translator.     

Temporal variation in pollinarium size after its removal in species of Bulbophyllum: A different mechanism preventing self-pollination in Orchidaceae

InBulbophyllum involutum andB. ipanemense (Orchidaceae), two closely related species, shortly after removal the pollinarium has a diameter of approximately twice that of the entrance of the stigmatic cavity, requiring a mean time of 105 to 135 minutes to shrink in width and allow pollination. Because the pollinators of these species remain for some minutes in the same flower after removing the pollinia this mechanism, previously unknown inOrchidaceae, may be very important in preventing self-pollination. This mechanism does not occur inB. weddellii, and the pollinator does not remain in the flower after removing the pollinia. The smaller diameter of the stigmatic cavity inB. involutum reduces by 50% the chances of interspecific pollination withB. weddellii, and interspecific crossing is strictly unidirectional. This is important in maintaining isolation between these sympatric species, which share the same pollinators and have synchronized flowering.     

Embryology and systematic position ofLiparis (Orchidaceae)

The embryology ofLiparis paradoxa andL. rostrata has been studied. The young anther wall consists of an epidermis, endothecium, three middle layers and secretory tapetum with uninucleate cells. In the mature anther, two or three sub-epidermal layers develop fibrous thickenings. The anther wall development corresponds to the massive type. Simultaneous cytokinesis results in decussate, isobilateral, linear, T-shaped and tetrahedral pollen tetrads. The pollinia are compact and at anthesis the pollen grains are 2-celled. Ovules are anatropous, bitegmic and tenuinucellate. Both the integuments are dermal in origin and 2-layered. Development of female gametophyte is of the monosporic, 8-nucleate type. Double fertilization occurs. The primary endosperm nucleus degenerates. The mature embryo is organized from the derivatives of tiers 1, 1, m, and n. Its development conforms to a variation of the Onagrad type. The seed coat is formed entirely by the outer layer of the outer integument. There are three sterile and three fertile valves in the ovary. In the prefertilization stages valves consist of parenchymatous cells. After fertilization, the sterile valves become sclerenchymatous whereas the fertile valves remain parenchymatous. The embryological characters support the disputed systematic position ofLiparis within subtribeLiparidinae ofEpidendreae.     

A phylogenetic analysis of the Euterpeinae (Palmae; Arecoideae; Areceae) based on morphology and anatomy

The Euterpeinae contains six neotropical genera. There has been continual disagreement on generic and subgeneric boundaries in the subtribe.Euterpe andPrestoea, andJessenia andOenocarpus, have been repeatedly united and separated. A phylogenetic analysis based on 54 morphological and anatomical characters gave one tree of 127 steps.Euterpe is separate fromPrestoea, butJessenia andOenocarpus are best treated as one genus. Subgeneric relationships ofEuterpe andOenocarpus are also analyzed and discussed.     

Androecial development and systematics inFlacourtiaceae s. l.

Androecial development of 13 species belonging to six tribes ofFlacourtiaceae has been investigated. While inScolopieae andFlacourtieae the stamens develop centrifugally, inErythrospermeae, Oncobeae andPangieae they are initiated in a centripetal sequence or a sequence that is neither distinctly centripetal nor centrifugal. The distribution of these developmental patterns coincides with the distribution of other characters (e.g. cyanogenic compounds, salicoid leaf teeth) and therefore supports a split of the family intoFlacourtiaceae s. str. (containing theScolopieae, Homalieae, Prockieae, Flacourtieae, Casearieae andBembicieae) andKiggelariaceae (withErythrospermeae, Oncobeae andPangieae) and is in accordance with results of recentrbcL studies.     

Sieve-element plastids,exine sculpturing and the systematic affinities of theBuxaceae

The sieve-element plastids of members of several genera in theBuxaceae (Buxus, Pachysandra andSarcococca) were found to be of the specific subtype PVI, which contains a central globular protein crystal.Simmondsia (Simmondsiaceae) andDaphniphyllum (Daphniphyllaceae), on the other hand, were found to contain S-type sieve-element plastids. The occurrence of the highly restricted PVI plastids in theBuxaceae mitigates against a close relationship between theBuxaceae andSimmondsia, Daphniphyllum andEuphorbiaceae. Exine sculpturing of theBuxaceae andSimmondsiaceae also shows no close similarities. Both of these EM characters are discussed in connection with other available data and with respect to earlier systematic treatment of these families.     

Evolution,pollination, and systematics of the tribeNeottieae (Orchidaceae)

The various classifications of the orchid tribeNeottieae are reviewed and a new classification is proposed that divides the tribe into three subtribes,Neottiinae, Limodorinae, andCephalantherinae, based primarily on characters of the column (gynostemium). A cladistic analysis illustrates that these three subtribes are more closely related to one another than either is to any other group in subfam.Neottioideae, although there are very few apomorphic characters for the tribe. Pollination biology is also discussed showing links between breeding systems and distribution. There is also a possible role between column and labellum morphology and the emergence of a deceptive pollination syndrome from one of reward.     

Anchusella, a new genus ofBoraginaceae from the Central-Eastern Mediterranean

The two closely related speciesLycopsis variegata andAnchusa cretica, formerly placed inAnchusa subg.Rivinia, were compared with the type species ofLycopsis andAnchusa, on the basis of a set of macro and microcharacters. The presence of only two fertile stamens as well as other peculiar characters in flower structure, androecium, gynoecium, pollen and fruit, supports the institution of the new genusAnchusella, consisting ofA. variegata andA. cretica. Karyological and eco-chorological aspects are consistent with morphological data in pointing to the autonomy of this genus, which appears characterized by autapomorphic, advanced traits.     

A phenetic study of the taxonomic delimitation of Quercus acutifolia and Q. conspersa (Fagaceae)

A phenetic study ofQuercus acutifolia andQ. conspersa (Fagaceae) is carried out. The study was based on morphological characters, and included cluster analysis and principal component analysis. The results revealed that the characters employed so far to separateQuercus acutifolia andQ. conspersa seem to be quite unreliable. Nevertheless, both species can still be recognized as taxonomically different entities, although mostly based on characters of leaf margins. We propose that the individuals that have leaves with dentate-aristate margins correspond toQ. acutifolia, whereas those that have leaves with entire and not dentate-aristate margins belong toQ. conspersa.     

Phylogenetic analysis ofUlmaceae

A phylogenetic analysis of theUlmaceae, Cannabaceae, Barbeyaceae, andBroussonetia of theMoraceae produced nine equally parsimonious trees with 127 steps. TheUlmoideae (Ulmaceae, sensuGrudzinskaya) are a monophyletic group and distinct from theCeltidoideae. The genusAmpelocera occupies an isolated taxonomic position among the celtidoids. The similarity ofAmpelocera to the fossil celtidoid flowerEoceltis of North America suggests thatAmpelocera posesses an archaic suite of characters, and occupies a primitive position among the celtidoids, theCannabaceae and theMoraceae. The relationships among the other celtidoid taxa,Cannabaceae, andBroussonetia are problematic. TheCannabaceae andBroussonetia of theMoraceae are nested within the celtidoids suggesting that this is a paraphyletic group. The close, but unresolved, relationship of the celtidoids to theMoraceae andCannabaceae observed in this analysis, and the appearance of the celtidoids in the fossil record prior to the ulmoids suggests that the evolutionary relationship of the ulmoids and celtidoids may be more distant than current taxonomic treatments reflect.     

The genusPicris (Asteraceae,Lactuceae) in Tropical Africa

Three species of the genusPicris L. are native in Tropical Africa:P. abyssinica Sch. Bip. (Ethiopia),P. xylopoda Lack, spec. nova (Nigeria, Ethiopia) andP. humilis DC. (Senegal, Mali). There are indications that the two perennial species,P. abyssinica andP. xylopoda, are related to and have evolved from a primitive Central Asiatic stock in a manner parallel to many African species ofCrepis L.P. humilis, on the other hand, is a small annual plant with a high number of derived characters. The introduced species of European origin growing south of the Sahara are briefly mentioned.     

Generic delimitation and phylogeny of theCarduncellus-Carthamus complex (Asteraceae) based on ITS sequences

Within the Mediterranean complexCarduncellus-Carthamus, taxonomic classification has proven problematic. Numerous attempts to clarify the relative systematic boundaries have included splittingCarduncellus andCarthamus into several genera, but none of these proposed classifications have been generally accepted. For a comprehensive resolution of the relationships within this group, we used sequences of the Internal Transcribed Spacers (ITS) of nuclear ribosomal DNA. The results indicate that the complex should be classified into four genera:Carduncellus, Carthamus, Femeniasia andPhonus. The relationship between the western group (Carduncellus, Femeniasia andPhonus) and the eastern genusCarthamus are not resolved by analysis of ITS sequences, but the two groups are probably not close relatives. The ITS classifications corresponded with biogeography and less with morphological characters, which have also been the main source of confusion in traditional classifications. Most of the unusual morphological features in theCarduncellus-Carthamus complex appear to be reversals to ancestral character states.     

Nutritional physiology of type isolates of currently accepted species ofExophiala andPhaeococcomyces

Nutritional physiological and tolerance tests were performed for all type strains of species currently classified in the black yeast generaExophiala andPhaeococcomyces, including some additional type strains of taxa recently reidentified asExophiala species. Most describedExophiala species can be distinguished by physiological characters.Exophiala jeanselmei with its varieties, andE. castellanii should all be retained as separate taxa. The pairs of strainsMycotorula schawii/Exophiala dermatitidis, Hormodendrum negronii/Exophiala jeanselmei var.lecaniicorni andSporotrichum gougerotii/Torula bergeri were found to be conspecific. Phenetic analyses of physiological data support the identity ofPhaeococcomyces exophialae as a yeast-like synanamorph ofExophiala spinifera. The taxonomic positions of the generaNadsoniella, Phaeoannellomyces andWangiella are discussed. The generaExophiala andPhaeococcomyces are unrelated.     

A phylogenetic analysis of the palm subtribe Oncospermatinae (Arecaceae) based on morphological characters

Subtribe Oncospermatinae (Arecaceae: Arecoideae: Areceae) is a diverse group of spiny Old World palms. The subtribe includesOncosperma, a widespread Asian genus of five species, along with seven monotypic genera, all endemic to the Seychelles and Mascarene Islands of the western Indian Ocean. A phylogenetic analysis was conducted in order to test the monophyly of subtribe Oncospermatinae with respect to other Old World genera of tribe Areceae. A matrix of 38 morphological characters was scored for 29 taxa, including 11 species of the Oncospermatinae. A single most parsimonious tree was found, resolving the subtribe as a polyphyletic group of two distinct clades. One clade containingAcanthophoenix, Deckenia, Oncosperma, andTectiphiala was placed as sister to a large group that includes members of subtribes Archontophoenicinae, Arecinae, Iguanurinae, and Ptychospermatinae. The other clade of Oncospermatinae, including the Seychelles endemic generaNephrosperma, Phoenicophorium, Roscheria, andVerschaffeltia, was resolved as sister to the Madagascar endemic subtribe Masoalinae, and may have arisen in the western Indian Ocean region.     

Pathways of karyological differentiation in palms (Arecaceae)

Karyological data are given for 56 palm taxa coming from all 6 palm subfamilies. In 11 genera and 17 species, chromosome numbers are reported for the first time. Most chromosome numbers in palms range between 2n = 36 and 2n = 26 in dysploid series. Species of the same genus usually exhibit identical chromosome numbers which additionally may be constant in larger groups of closely related genera (Coryphoideae trib.Corypheae with nearly always 2n = 36,Arecoideae subtribesEuterpeinae andRoystoneinae with 2n = 36,Arecoideae subtrib.Butiinae with mostly 2n = 32). Polyploidy among palms is of minor significance but the endemic Madagascan genusVoanioala (2n = 606 ± 3) is the most striking exception. — With respect to structure of interphase nuclei and longitudinal differentiation of prophase and metaphase chromosomes, the palm family is highly differentiated. Euchromatin types with different prophase condensation properties and fluorochrome and C-banding patterns of heterochromatin permit a discrimination of several subfamilies on the nuclear level (Arecoideae, Ceroxyloideae, Nypoideae, Phytelephantoideae, Calamoideae).Arecoideae andCeroxyloideae, andNypoideae andPhytelephantoideae have some features in common. Subfam.Coryphoideae s. l. is a non-uniform group. — Nuclear characters among palms exclusively found in recentCoryphoideae subtrib.Thrinacinae link palms with other monocotyledons. Most probably, such a nuclear condition represents an ancestral state in the evolution of palm genomes within subfam.Coryphoideae s. l., but also the conspicuous nuclear characters of the other modern palm subfamilies appear to be derived from a similar starting point, since transitional character states are still present in subfam.Calamoideae and some taxa of subfam.Arecoideae. Early karyoevolution in palms obviously did not involve numerical change of the ancient chromosome number of 2n = 36 which started subsequently, as a dysploid reduction in numerous parallel series, independent in subfam.Coryphoideae (2n = 36 to 2n = 28),Calamoideae (2n = 36 to 2n = 26),Ceroxyloideae (2n = 34 to 2n = 26), andArecoideae (2n = 36 to 2n = 28). Possible mechanisms of karyological change are discussed. — Karyological characters are compared to morphological, ecological, taxonomical, and chorological features, and give some new insight into older and more recent phases of palm evolution. (1) Strong deviations in vegetative or floral morphology are often accompanied by major karyological differences, and sometimes the direction of advancement can be traced through intermediate stages. (2) Apart fromCoryphoideae subtrib.Thrinacinae, the strongest concentration of apparently original karyological traits is found in the more basal members of each subfamily. (3) The most successful and actively radiating colonizers of the forest floors in evergreen tropical forests which belong to completely different subfamilies (Old WorldLicuala, New WorldChamaedorea andGeonoma), appear to be very advanced karyologically.     

Molecular phylogenetics of subtribe Aeridinae (Orchidaceae): insights from plastid matK and nuclear ribosomal ITS sequences

We conducted phylogenetic analyses using two DNA sequence data sets derived from matK, the maturase-coding gene located in an intron of the plastid gene trnK, and the internal transcribed spacer region of 18S–26S nuclear ribosomal DNA to examine relationships in subtribe Aeridinae (Orchidaceae). Specifically, we investigated (1) phylogenetic relationships among genera in the subtribe, (2) the congruence between previous classifications of the subtribe and the phylogenetic relationships inferred from the molecular data, and (3) evolutionary trends of taxonomically important characters of the subtribe, such as pollinia, a spurred lip, and a column foot. In all, 75 species representing 62 genera in subtribe Aeridinae were examined. Our analyses provided the following insights: (1) monophyly of subtribe Aeridinae was tentatively supported in which 14 subclades reflecting phylogenetic relationships can be recognized, (2) results are inconsistent with previous classifications of the subtribe, and (3) repeated evolution of previously emphasized characters such as pollinia number and apertures, length of spur, and column foot was confirmed. It was found that the inconsistencies are mainly caused by homoplasy of these characters. At the genus level, Phalaenopsis, Cleisostoma, and Sarcochilus are shown to be non-monophyletic.     

Generic delimitation of Aralia (Araliaceae)

Aralia, described by Linnaeus, remains a poorly defined genus. Many satellite genera ofAralia have been proposed, and some have been accepted without critical evaluation. These genera includeCoudenbergia, Megalopanax, Parapentapanax, andPentapanax. This study examined the historical background of the establishment of these genera and their diagnostic characters. It was found that (1)Aralia s. str. is a relatively diverse genus; (2) the separation ofPentapanax andParapentapanax fromAralia is unsubstantiated; (3)Megalopanax is synonymous withCoudenbergia; and (4) the boundaries betweenAralia and bothCoudenbergia andPentapanax intergrade. It is proposed, therefore, to mergeCoudenbergia, Parapentapanax, andPentapanax withAralia, which has nomenclatural priority.Aralia is herein defined as consisting of those species in Araliaceae with pinnate leaves, articulated rachises, five to eight-merous flowers, petals imbricate in buds, and articulated pedicels. The revised generic concept requires the following new combinations or new names:Aralia castanopsisicola, A. franchetti, A. gigantea, A. laevis, A. leschenaultii, A. parasitica, A. rex, A. subcordata, A. verticillata, andA. warmingiana.     

A discussion of the classesChlamydophyceae andChlorophyceae and their subordinate taxa

The diagnostic characters alleged byEttl (1981) andEttl &Komarek (1982) to distinguish the ClassesChlamydophyceae andChlorophyceae are discussed. The recognition of these classes ignores ultrastructural evidence of the close phylogenetic relationships of their members and produces an artificial redistribution of orders, families, and genera that can only lead to confusion in the taxonomy of the green algae. Suggestions for a more natural classification are made.