Corolla Morphology Research Articles

CAN THE SECTIONAL POSITION OF GENTIANA CACHEMIRICA BE CLARIFIED BY A DETAILED ANALYSIS OF ITS MORPHOLOGY?

Gentiana cachemirica is a rare plant from northern Pakistan and northwestern India. The sectional position of this species has been a matter of considerable debate. Various authors have placed Gentiana cachemirica in one of three different sections – Gentiana sect. Isomeria, Gentiana sect. Kudoa or Gentiana sect. Pneumonanthe. The present paper assesses the taxonomic affinities of this species using a detailed study of its morphology accompanied by morphological phylogenetic and cluster analyses. Characters of the seed testa, corolla morphology and growth architecture were studied for selected species from the above-mentioned sections and closely related Gentiana sect. Cruciata. Representatives of Gentiana sect. Ciminalis were used as outgroups. Our results suggest that G. cachemirica belongs to Gentiana sect. Pneumonanthe and that its affinities are closer to the Western Asiatic group of this section.

Pollination Ecology of Pedicularis Muscoides H. L. Li subsp. himalayca Yamazaki from Alpine Areas of Western Sichuan, China

ABSTRACTThe pollination ecology of small, short, and two-flowered Pedicularis muscoides subsp. himalayca was studied during its full blooming period in alpine areas of western Sichuan Province, China, part of the putative origin and diversification center of the genus. Pedicularis muscoides subsp. himalayca was nototribically pollinated exclusively by queens of four bumblebee species (Bombus Latr.) that foraged for nectar on flowers in an upright position. Of the four Bombus species, B. friseanus Smith occurred in the highest frequency and was the major pollinator of P. muscoides subsp. himalayca. It comprised 81% of the bumblebees collected on P. muscoides subsp. himalayca. Queen bumblebees stood on the ground while foraging on flowers, which has not previously been reported in other Pedicularis species. During the study period almost all the foragers were confined to the studied subspecies and very occasionally visited other associated blooming species at the study site. The low plant height; outcurved terminal flowers; short-tubed, erostrate, and copiously nectariferous flowers; corolla morphology; and highly synchronized short-blooming period of P. muscoides subsp. himalayca made this plant well adapted to pollination by queen bumblebees within a short growing season. Thus this study provides evidence for coadaptation between Pedicularis and bumblebee pollinators.

Evolutionary Relationships Within the Species-Rich Genus Ruellia (Acanthaceae)

Abstract Phylogenetic relationships among species of the large genus Ruellia (Acanthaceae) have never been studied. Ruellia, with approximately 300 species, is geographically widespread and morphologically diverse. Molecular data for 196 specimens from the nuclear ribosomal ITS region and the chloroplast trnG-trnR region were used to test monophyly of the genus against closely related genera in Ruellieae, to reconstruct phylogenetic relationships among species of Ruellia on a global scale, to re-evaluate previous morphology-based classifications, and to examine the utility of morphological characters, especially corolla morphology, for future sectional delimitation. Bayesian and parsimony analyses indicate four genera are evolutionarily allied to Ruellia. Acanthopale is sister to Ruellia s. l. with strong support. Blechum, Eusiphon, and Polylychnis are nested within Ruellia s. l., and species in Eusiphon and Polylychnis are here formally transferred to Ruellia resulting in the new combinations Ruellia gea...

Absence of Long‐Proboscid Pollinators for Long‐Corolla‐Tubed Himalayan Pedicularis Species: Implications for the Evolution of Corolla Length

The genus Pedicularis manifests great variation in corolla morphology, including corolla tube length. Previous observations conducted during daytime have documented bumblebees to be important pollinators for short‐ and long‐tubed Pedicularis species. However, the potential role of night‐flying long‐proboscid insects (moths) as selective agents for the evolution of corolla length has not been determined. Three Pedicularis species, Pedicularis densispica, Pedicularis gruinea, and Pedicularis siphonantha, in montane meadows of Yunnan Province, southwestern China, have extremely divergent corolla tube lengths of 7.1, 22.0, and 50.6 mm, respectively. We find that all three species are pollinated by similar bumblebee species. Pollination treatments indicate that seed sets of inflorescences enclosed in fine‐meshed nylon nets in the night are not different from open‐pollinated inflorescences, but those bagged in the day have significantly decreased seed set, indicating that moth pollinators are not important for ...

Morphological Delimitation and Molecular Evidence for Allopolyploidy in <I>Collomia wilkenii</I> (Polemoniaceae), a New Species from Northern Nevada

Abstract Under the criterion of limited homogenizing gene flow as evidenced through specimen aggregation analysis, and genetic evidence of a barrier to gene exchange with its closest relatives, we describe a new species in Polemoniaceae, Collomia wilkenii. Collomia wilkenii superficially resembles Collomia tinctoria and Collomia linearis in some features, but, upon examination, has consistent, unique character combinations that distinguish it from both species, as well as from sympatric Collomia renacta and Collomia tenella. These features include particulars of calyx morphology, corolla morphology, stamen insertion and exertion, numbers of flowers in inflorescence clusters, and the kinds and distribution of glandular and eglandular trichomes. Comparative DNA sequencing of chloroplast genes indicates Collomia wilkenii has the chloroplast genome of Collomia tenella. Nuclear ITS sequences show additivity in Collomia wilkenii between Collomia linearis and Collomia tenella, a pattern confirmed by cloning this...

Morphology and evolution of the corolla and corona in the Apocynaceae s.l.

Morphology and evolution of the corolla and corona in the Apocynaceae s.l.

Phylogenetic Relationships among Acantheae (Acanthaceae): Major Lineages Present Contrasting Patterns of Molecular Evolution and Morphological Differentiation

Abstract We used DNA sequence data from four regions ([1] nrITS; the chloroplast [2] rps16 intron, [3] trnG-S spacer, and [4] trnL-F intron and spacer) to study phylogenetic relationships within tribe Acantheae (Acanthaceae). Our sample includes 18 of 20 recognized genera and 82 of ca. 500 species (plus two Justicieae as out-groups). Results of parsimony and Bayesian analyses were entirely congruent and provided strong support for monophyly of two sub-lineages of Acantheae, referred to here as the ‘one-lipped corolla’ and ‘two-lipped corolla’ lineages, reflecting notable differences in corolla morphology. Subsequent analyses were of the two sublineages separately in order to include all characters (a hypervariable region of trnG-S could not be aligned across the full range of taxa but could be aligned within sublineages). The ‘one-lipped corolla lineage’ comprises six clades of Old World taxa related as follows: [Crossandra (Sclerochiton clade {Cynarospermum [Blepharis (Acanthus clade + Acanthopsis)]})]. ...

Phylogeny and the Evolution of Floral Diversity in Pedicularis (Orobanchaceae)

Pedicularis has a conflicted infrageneric taxonomic history in which floral and vegetative characters have alternately been interpreted as primary indicators of common ancestry. Recent classifications favor subgenera delimited by similarity in leaf arrangement, on the basis of the premise that corolla morphology has been subject to pollinator‐mediated selection, resulting in the convergent evolution of specialized floral forms from generalized ancestors. In this study, molecular phylogenetic analysis of Pedicularis reveals a low concordance of robust clade support and taxonomic groups. Nevertheless, the basic premise of higher homoplasy in floral characters relative to leaf arrangement is confirmed, although the hypothesized direction of change (from short‐tubed, beakless, toothed corollas to long‐tubed, beaked, toothless forms) is not uniformly upheld. In spite of the high evolutionary lability of floral form in Pedicularis, some character state combinations are rarely or never observed, suggesting functional constraints. Correlation analysis shows a significant association between curved‐rostrate corollas (a marker for nectar production) and long corolla tubes, indicating that access to nectar by pollinators has acted as a constraint on the evolution of corolla tube length.

Corolla Morphology Facilitates Both Autogamy and Bumblebee Pollination in Mimulus guttatus

The showy corolla of Mimulus guttatus is generally considered an adaptation to attract pollinators. We use phenotypic manipulations to demonstrate that corolla morphology plays a critical mechanical role in both outcrossing and self‐fertilization. In the absence of pollinators, the lower portion of the corolla facilitates autogamy by retaining pollen released from the anthers. A substantial portion of self‐fertilization seems to occur late in the floral life span as the stigma contacts the corolla. When pollinators are present, the corolla facilitates outcrossing before, during, and after insect visitation. A large fraction of cross‐pollen is actually captured by the corolla and not by the stigma. This “indirect” pathway for pollen reception suggests that a large fraction of cross‐pollination in M. guttatus actually occurs long after a pollinator departs from a flower.

FLORAL MORPHOLOGY AND RECOGNITION OF VARIETIES IN CONANDRON RAMONDIOIDES (GESNERIACEAE) FROM JAPAN AND TAIWAN

Comparisons of corolla morphology were made between plants of Conandron ramondioides (Gesneriaceae) from 23 localities in Japan and Taiwan. Lobe-length to tube-length ratios were found to correlate with geographical distribution and support the recognition of two previously described varieties: var. ramondioides in mainland Japan (lobe length less than twice tube length) and var. taiwanensis from Iriomote Island (Japan) and Taiwan (lobe length more than three times tube length). Mitotic chromosomes were also observed but no differences were seen between accessions, all of which had 2n=32.

Molecular phylogenetic evidence for the geographic origin and classification of Canary Island Lotus (Fabaceae: Loteae)

Molecular phylogenetic analyses of Macaronesian Lotus and related genera were conducted to assess their biogeographic history and taxonomy. Macaronesian Lotus, which are typically classified within one of two subgenera, Lotus subgenus Pedrosia or L. subg. Rhyncholotus, are diagnosed by the presence of a forked or toothed style and differences in corolla morphology. Maximum parsimony and Bayesian analyses of internal transcribed spacer sequences identify a well-supported northwest African-Cape Verde Island clade that includes all members of Lotus subgenus Pedrosia + L. subg. Rhyncholotus. There is modest support for two independently nested clades containing the Canary Island species and two non-Canarian species, Lotus assakensis from Africa and Lotus azoricus endemic to the Azores. Biogeographic reconstruction based on a parsimony topology unequivocally identifies an African origin for the Canary Island group with subsequent back dispersal to the African continent and a single dispersal event to the Azores. A phylogeographic assessment of colonization and diversification patterns suggests that geographic isolation via interisland colonization of ecologically similar habitats is the primary mode of species diversification in Canary Island Lotus.

Nectar production in three melliferous species of Lamiaceae in natural and experimental conditions

The nectar production of Lamium maculatum, Lamiastrum galeobdolon and Ajuga reptans was evaluated by determining the Index of nectar production (INP) total nectar quantity per flower during 24h, nectar sugar concentration flowering period, flower longevity, and flower number per plant and per square unit. The diurnal dynamics of nectar secretion in these three melliferous species, grown under different microclimatic habitat conditions (natural and experimental field) was also analyzed, by measuring the amount of nectar per flower at two hour intervals. Nectar amount and sugar concentration varied among the studied species as a function of microclimatic habitat conditions (air temperature, air humidity and evaporation) and corolla morphology. Higher nectar production and lower sugar concentration were recorded in L. maculatum and L. galeobdolon grown in the forest, while for A. reptans in the same habitat, lower intensity of nectar secretion and higher sugar concentration were obtained. With regard to the average number of open flowers per plant during the nectar collecting day, total daily nectar volume per plant was the highest in L. maculatum (average volume 30.1 ml/plant). Considering the average size or density of the natural population of the species, the highest nectar yield per square unit was found in L. maculatum (1564.99 ml/m2) and the lowest in A. reptans (111.34 ml/m2). Diurnal variation in nectar production was also found and the secretion patterns were rather different in these three melliferous species. Regarding nectar secretion rate, A. reptans is a slow producer, secreting less than 0.02 ml/h. With respect to secretion intensity (on average 0.22 ml/h), total daily nectar production per flower (on average 5.368 ml) and the density of species population, the most melliferous species was L. maculatum.

A NEW SPECIES OF STREPTOCARPUS (GESNERIACEAE) FROM THE PONDOLAND COAST, SOUTH AFRICA

The new species Streptocarpus lilliputana (Gesneriaceae), collected on the Pondoland coast, South Africa, is described. Although its alliances are not obvious in terms of corolla morphology and rosulate habit, it approaches S. gardenii and its allies. The pollen and stigma of S. lilliputana differ markedly from the stenopalynous grains and bilobed stigmas of the other South African rosulate species. Streptocarpus lilliputana is exceedingly rare and is a further endemic from the Pondoland centre.

Pollen morphology and infra-generic evolutionary relationships in some Chinese species of Pedicularis (Scrophulariaceae)

The pollen grains of 32 Chinese species of Pedicularis representing 13 groups within the genus were investigated using light microscopy and scanning electron microscopy. The genus is eurypalynous, the apertures may be tricolpate, trisyncolpate, or bisyncolpate and five types of surface ornamentation (microscabrate, microrugulate, retipilate, microreticulate and microfoveolate) were observed. Comparison of the different aperture types using light microscopy allows three pollen types to be distinguished. Examination of exine ornamentation with scanning electron microscopy enabled each pollen type to be divided into two or three sub-types (giving a total of seven sub-types). Pollen morphology within the genus is discussed in relation to infrageneric relationships, evolutionary and pollination biology. There is little correlation with the existing infrageneric taxonomy (some taxonomic groups have more than one pollen type, while the same pollen type may be found in several different species-groups), but greater correlation with the corolla morphology.

Reinstatement of the genus Macledium Cass. (Asteraceae, Mutisieae): morphological and phylogenetic arguments

SummaryOrtiz, S.: Reinstatement of the genus Macledium Cass. (Asteraceae, Mutisieae): morphological and phylogenetic arguments. ‐ Taxon 50: 733–744. 2001. ‐ISSN 0040‐0262.Studies of the genus Dicoma Cass. (Asteraceae, tribe Mutisieae) indicate that this taxon as currently defined is paraphyletic, and in fact comprises three groups showing marked morphological and anatomical differences. One of these groups is differentiated from Dicoma s.str. by a large number of characters relating to morphology and anatomy of phyllaries, corolla, anthers, style, cypsela, and testa. It is proposed that these species should be considered as a separate genus, for which the name Macledium Cass. has nomenclatural priority. A brief nomenclatural synopsis is presented, including synonyms and nomenclatural types for each taxon in this genus of 20 species.

Chemically induced floral morphological mutations in two cultivars of Ipomoea purpurea (L.) Roth

Two cultivars of Ipomoea purpurea (Morning Glory) differing in flower colour and corolla morphology were investigated for artificial mutagenesis. The violet blue (VB) cultivar bears flowers with a typical gamopetalous corolla. The red purple (RP) cultivar has flowers with an incised corolla at one or more places at the petal union, i.e. incompletely gamopetalous and has petaloid appendages borne on the outer side. It has been described as petalomaniatic. The petaloid appendages were part and parcel of the petal itself. The mutagens used were ethyl methanesulfonate (EMS), N-methyl- N′-nitro- N-nitrosoguanidine (NMG) and sodium azide (SA). Mutants affecting the petal union and petalomaniatic tendency were discussed. It was possible to induce an incompletely gamopetalous petalomaniatic mutant in cultivar VB as well as the typical gamopetalous corolla morphotype in cultivar RP. Preliminary hybridization studies were made using cv. RP and its white colour mutant as one of the parents and crossed with cv. VB. Hybridization studies revealed that independent loci exist for the incomplete gamopetalous nature of the corolla and its petalomaniatic tendency. The mutants obtained were corolla whorl specific and were described as meristic mutations in I. purpurea.

Taxonomic Notes on the Tribe Psychotrieae (Rubiaceae) in Panama, Western Colombia, and Ecuador

Taxonomic Notes on the Tribe Psychotrieae (Rubiaceae) in Panama, Western Colombia, and Ecuador

The Genus Streptosiphon (Acanthaceae : Acantheae)

During fieldwork on the Rondo Plateau, Lindi District, Tanzania in 1991 four collections were made of Streptosiphon hirsutus, a monotypic genus which was previously known from only two collections. These collections were all made within an area of a few square kilometres and, as far as can be ascertained, in the same area where the first two collections were made. This new material includes fruit and seeds, and has made it possible to produce a more detailed description and to make a more qualified evaluation of the affinities of this extraordinary plant. The peculiar corolla morphology immediately makes this plant stand out. The corolla (Fig. IF) has an entire or very indistinctly lobed ventral lip and no dorsal lip. The lip, however, at first sight appears to be dorsal because the corolla tube is twisted 1800 lengthwise. Furthermore, only the tip of the corolla limb protrudes above the large bracts (Fig. 1A) making the corolla look rather like the periscope of a submarine appearing above the surface.

A Reconsideration of Asystasiella Lindau (Acanthaceae)

Summary. Asystasiella is considered for the moment to include two species, A. atroviridis (T. Anders.) Lindau from Bangladesh and Assam, and A. africana S. Moore from S. E. Kenya and N. E. and E. C. Tanzania. Its spheroidal, porate, spinulate pollen is very different from that of Asystasia and other related genera. However, the two species now included have a different corolla morphology. The related genus Odontonemella is sunk into Mackaya. A new lectotype is designated for the name Asystasiella.

Siphocampylus oscitans (Campanulaceae: Lobelioideae), A New Name for Burmeistera Weberbaueri from Peru

Burmeistera weberbaueri is transferred to the genus Siphocampylus under the new name Siphocampylus oscitans. The species is noteworthy in being one of only three species of Siphocampylus known to have a dilated anther-tube orifice. As part of a reassessment of the Peruvian members of Burmeistera (Stein, 1987), it has become apparent that B. weberbaueri Zahlbr. actually belongs to the large Andean genus Siphocampylus. This paper makes the appropriate generic transfer and proposes a new name to accommodate this unusual species. Generic delimitations in Campanulaceae subfamily Lobelioideae have long been recognized as problematic (Gleason, 1925; McVaugh, 1940). Traditional systems, such as those of Presl (1836) and Wimmer (1943), rely heavily on fruit morphology for classification at the tribal level. In particular, capsular versus baccate fruit is a fundamental character used to define and align genera. Strict reliance on this dichotomy in the classification ofthe subfamily has separated close relatives, for example, capsular-fruited Siphocampylus and baccate-fruited Centropogon. Although fruit type in conjunction with other features can be reliable for clustering related groups of species, probable convergence in fruit characters suggests caution in its application. Among neotropical Lobelioideae the emphasis on fruit type, and to a lesser degree on the presence or extent of a dorsal slit in the corolla (another seemingly labile character), has yielded _genera .of convenience. -aOze of-the most natural groupings, however, appears to be the genus Burmeistera, which is characterized by baccate fruits, oblong or linear seeds, mostly nonbracteolate pedicels, entire corolla tubes, and distally open and oblique anther tubes often with little or no apical pubescence. The distally open anther tube of Burmeistera is one of its most distinctive features. In most genera of Lobelioideae the three dorsal anthers are longer than the two ventral ones and curve downward at the apex, effectively closing the mouth of the anther tube. This allows the internally released pollen to build up pressure as the style and stigma elongate, pushing pistonlike through the anther tube. The characteristic tuft of stiff hairs at the tip of the ventral anthers functions as a lever that opens the orifice slightly and allows the pressurized pollen to discharge. Presumably tripped by flower visitors, this action has been elegantly documented in Isotoma petraea by Brantjes (1983) and has been observed in the neotropical genera Centropogon and Siphocampylus (Stein, in prep.). Since the dorsal anthers in Burmeistera do not curve downward closing the anther tube, this type of regulated pollen discharge does not occur. This difference in pollen presentation probably explains the correlated feature of glabrous or only sparsely pilose anther apices in Burmeistera sect. Imberbes F. Wimmer: apical hairs there have no function as trip mechanisms. Whether the densely villous tuft at the tip of the ventral anthers in Burmeistera sect. Barbatae F. Wimmer has a functional role -in.pollen d-ischarge is not clear. Burmeistera weberbaueri was included in this genus by Zahlbruckner (1906) on the basis of floral features alone, as he had no mature fruit. This decision was probably based upon his observation of a naked and dilated anther-tube orifice, the absence of bracteoles, and the somewhat I I am grateful to Carlos Reynal for locating the type specimen at MOL and to B. E. Leuenberger for searching for type material at B. Dan H. Nicolson kindly provided advice regarding lectotypification, and Porter P. Lowry II and Peter Goldblatt made useful suggestions on-an earlier draft. Fieldwork in Peru was supported by National Science Foundation Doctoral Dissertation Improvement Grant BSR84-13912 and by a Garden Club of America Award in Tropical Botany. 2 Missouri Botanical Garden and Washington University. P.O. Box 299, St. Louis, Missouri 63166-0299, U.S.A. ANN. MissouRI BOT. GARD. 74: 491-493. 1987. This content downloaded from 207.46.13.43 on Wed, 25 May 2016 04:52:59 UTC All use subject to http://about.jstor.org/terms 492 ANNALS OF THE MISSOURI BOTANICAL GARDEN [VOL. 74 burmeisteroid corolla morphology (a short, straight tube with an abruptly ampliate throat and falcate lobes). The strongly turbinate hypanthium visible in the Field Museum type photograph suggests the mature fruit of this species to be capsular rather than baccate. Furthermore, the coriaceous and rugose texture of the leaves characterizes many members of Siphocampylus but is unknown in Burmeistera. An open anthertube orifice of the kind described by Zahlbruckner is, however, extremely rare in Siphocampylus.