Inflorescence Characters Research Articles

Aromatherapy: a survey of current practice in the management of rheumatic disease symptoms

In this investigation, morphological, phytochemical and ISSR markers were used to estimate the relationships among and within seven populations of white savory (Satureja mutica), belonging to four provinces in Iran. The individuals were phenotypically diverse, which stamen length, corolla length, corolla diameter, calyx length, bract length, inflorescence length, calyx length and bracteole width were characteristics with the highest variation. Leaf dimensions were in significant correlation with flower and inflorescence characteristics. Chemical compounds of essential oils were found variable in various individuals and all samples were principally composed of phenolic constituents (carvacrol and/or thymol). As a consequence, the plants were classified into two major chemotypes including carvacrol and thymol. A total of 197 band positions were produced by 14 ISSR primers, of which 176 were found polymorphic with 88.91% polymorphism. ISSR genetic similarity values among individuals ranged between 0.45 and 0.94 which was indicative of a high level of genetic variation. Multiple regression analysis (MRA) revealed that phytochemical compositions as dependent variable, showed statistically significant correlation and in association with leaf and flower traits as independent variable, indicating a main role of leaf and flower on production of these compounds. Also, several ISSR fragments were found associated with some morphological traits and phytochemical compositions. The high diversity within and among populations of S. mutica according to different data systems could provide useful information for conservation and selection of cross-parents in breeding programs.

A preliminary revision of the supraspecific classification of Kobresia Willd. (Cyperaceae)

Previous supraspecific classifications of the genus Kobresia are evaluated. The evolution of the genus is discussed, and a preliminary revised supraspecific classification based on putative evolution is proposed. Previous classifications were mostly based on inflorescence characters. The spicate inflorescence might have evolved in parallel from a paniculate one, and unisexual spikelet might also be the result of parallel evolution from bisexual spikelets. Therefore, the subgenera or sections Elyna and Hemicarex, which were recognized by previous authors and characterized by the spicate inflorescence (the former with bisexual spikelets and the latter with unisexual ones), may be polyphyletic. In the classification presented here, three subgenera are recognized. A new subgenus Blysmocarex (N. A. Ivanova) S. R. Zhang is proposed. A key to subgenera and sections is included, and types, synonymies and representative species are given under each supraspecific rank.

A preliminary revision of the supraspecific classification of Kobresia Willd. (Cyperaceae)

Previous supraspecific classifications of the genus Kobresia are evaluated. The evolution of the genus is discussed, and a preliminary revised supraspecific classification based on putative evolution is proposed. Previous classifications were mostly based on inflorescence characters. The spicate inflorescence might have evolved in parallel from a paniculate one, and unisexual spikelet might also be the result of parallel evolution from bisexual spikelets. Therefore, the subgenera or sections Elyna and Hemicarex, which were recognized by previous authors and characterized by the spicate inflorescence (the former with bisexual spikelets and the latter with unisexual ones), may be polyphyletic. In the classification presented here, three subgenera are recognized. A new subgenus Blysmocarex (N. A. Ivanova) S. R. Zhang is proposed. A key to subgenera and sections is included, and types, synonymies and representative species are given under each supraspecific rank.

Alternaria alternata Causing Flower Stem Blight of Lupinus havardii.

Lupinus havardii Wats., commonly known as Big Bend or Chisos bluebonnet, is a showy winter annual that can reach 1.0 to 1.5 m in height and produces blue, fragrant inflorescence (racemes). L. havardii is native to a narrow geographic range along the Mexican border in southwest Texas. The inflorescence of L. havardii has considerable potential in the cut flower industry where there is a need for high-quality, durable flowers with a blue color (1). Several crops have been produced in the greenhouse to determine production and post-harvest characteristics of the cut inflorescence. Under greenhouse growing conditions during March through June 1999, numerous plants of L. havardii cv. Texas Sapphire grown in raised beds and in containers in both Dallas and El Paso, TX, were observed with blighted flower racemes with light brown to gray lesions ranging from 1 to 5 cm in length. The racemes were attacked at varying ages and eventually assumed a hooked appearance where the terminal 15 cm of the raceme was bent downward. Isolations from symptomatic lesions removed from L. havardii flower stalks consistently yielded cultures of an Alternaria sp. on potato-dextrose agar. Typical conidia measured 27 μm length and 11 μm width with 3 to 5 transverse septa. The fungus was identified as A. alternata (Fries) Keissler consistent with the description in Ellis (2). Pathogenicity tests were conducted in the laboratory by inoculating cut inflorescences with agar disks containing the fungus. Inoculations produced light brown lesions on the racemes that were typical of disease symptoms observed on greenhouse crops. In addition to the blue-flowered Texas Sapphire cultivar, we also observed the disease symptoms on pink and white flowered breeding lines of L. havardii. This disease is important as a flower stem blighting pathogen and could severely restrict production of cut flowers during the growing season. This is the first report of Alternaria sp. attacking L. havardii.

A new species of Leptothrium (Zoysieae, Poaceae) from Somalia

Summary A new species of Leptothrium, L. somalense, is described from the coast of south-central Somalia. It is close to L. senegalense from which differs in the size, characters of inflorescence and spikelets, size and shape of the glumes.

Identidad de dos especies sudamericanas de Rhynchospora (Cyperaceae): R. rostrata y R. organensis

Guaglianone, E. R. & Moore, G. 2001. Identity of two South American species of Rhynchospora (Cyperaceae): R. rostrata and R. organensis. Darwiniana 39(3-4): 239-246. The name Rhynchospora rostrata has been applied to two different species of Rhynchospora (subgn. Haplostylis, sect. Longirostres) from South America. True R. rostrata is known only from Brazil (Distrito Federal, Goias, Minas Gerais). The correct name for the other species going under the name R. rostrata is R. organensis, and it is known from Argentina, Brazil, Paraguay, and Uruguay. R. organensis returns to the status of species after being considered as R. corymbosa var. organensis. R. corymbosa, R. rostrata and R. organensis can be distinguished using inflorescence and achene characters, and a key to differentiate them is provided. R. rostrata and R. organensis are also described and illustrated.

Pollen morphology of Brunellia (Brunelliaceae) and related taxa in the Cunoniaceae

Pollen grains of 24 species of Brunellia were examined with LM and SEM, in order to find additional taxonomic information for phylogenetic analysis. The pollen grains were found to be 3- colporate, tectate and to have variable exine pattern. Five types of exine pattern were observed: striate-reticulate (large lumina and high muri) to finely reticulate, modified reticulate (muri and lumina irregular in shape and at various levels), modified rugulate (irregular and with protruding tectal elements) and punctate (the lumina are smaller and rounded to slit-shaped). With reference to indication of taxonomic relationships the exine pattern is not informative at all; however it is useful, for defining taxonomic species as it is correlated to vegetative, inflorescence and fruit characteristics. It seems that the punctate type could be a plesiomorphic character while modified reticulate is a synapomorphy. Relationships in the pollen morphology of Brunellia and certain genera of Cunoniaceae are discussed. El polen de 24 especies de Brunellia fue examinado en el microscopio de luz (ML) y el microscopio electrónico (MES) para encontrar información taxonómica adicional y usar esta información en el estudio de relaciones filogenéticas. El grano de polen es 3-colporado, tectado y con una alta variabile ornamentación de la exina. Se observaron cuatro categorías en la ornamentación de la exina del grano de pollen: reticulado estriado (luminas grandes y muros altos) a finamente reticulado, reticulado modificado (muros y lúminas de forma irregular y en varios niveles), rugulada modificada (irregular y proyectando elementos tectales) y la ornamentación de tipo punteado (las lúminas son pequen∼as redondeadas o en forma de líneas). Desde el punto de vista de relaciones filogenéticas la ornamentación de la exina es parcialmente un carácter informativo. Sin embargo, la ornamentación es útil para definir las especies taxonomicamente por la correlacion de este carácter con caracteres vegetativos, de inflorescencia o del fruto. El tipo de ornamentación punteado parece ser el estado plesiomórfico, mientras que la ornamentación modificada reticulada es una sinapomorf´ L a. Se discuten las relaciones del grano de polen de Brunellia y ciertos géneros de Cunoniaceae.

A New Species of Rungia (Acanthaceae) from Cameroon

Description of a new species, Rungia camerunensis. It is illustrated and a distribution map is given. Risumi.- Une nouvelle espice de Rungia (Acanthaceae) du Cameroun. Une nouvelle espkce, Rungia camerunensis, est ddcrite. Une illustration et la carte de distribution de l'espkce sont donndes. The paleotropical genus Rungia comprises more than twenty-five species of which ten occur in continental Africa and one, R. rosacea Lindau, is endemic to Madagascar. There has not been any treatment of the African species of the genus since the 'Flore du Gabon' (Heine 1966) and 'Flora of West Tropical Africa' (Heine 1963). Rungia guineensis Heine and R. eriostachya Hua are restricted to western Africa whereas R. schliebenii Mildbr. occurs in eastern Africa. Rungia paxiana (Lindau) C.B.C1. extends from West Africa to Cameroon. Rungia congoensis C.B.C1. is recorded from Niger to Central Africa. Rungia grandis T.Anders. and R. buettneri Lindau are the most widespread in tropical Africa. Rungia caespitosa Lindau from Cameroon and R. dimorpha S.Moore from West Africa are badly known. The new species, R. camerunensis, belongs to the group of small herbaceous somewhat subshrubby species not exceeding 100 cm in height. The closest relative of Rungia is the genus Justicia. The two genera can be distinguished easily when ripe fruits are available. In mature fruits of Rungia, when the upper part of the capsule valves bend away from each other, the placentas and part of the adjacent capsule walls separate from the valves, the placentas rising but remaining attached apically. In most species of Justicia, the fruit is the loculicidally opening two-valved capsule without rising placentas typical in the Acanthaceae. But an intermediate fruit structure was found in the New World Section Leucoloma V.A.W.Graham and the species J. gendarussa Burm.f., in which the placentas rise and separate from the capsule walls (Graham 1988). Hansen (1989) also mentioned several SE Asian species which show this condition. No mention has been made of the presence of this intermediate fruit structure in the African species of Justicia, so the latter and Rungia are easily distinguished. Unfortunately, there is no fruit material available for the new species described here. However, according to Hansen (1989) the two genera can also be distinguished by inflorescence characters with Rungia possessing one 'sterile' (without flower) and one 'fertile bract' (subtending a flower) at each node of the inflorescence, while in Justicia both bracts are 'fertile'. This has been verified in the material studied here which without doubt belongs to the genus Rungia.

Two New Species of Acritopappus (Compositae: Eupatorieae: Ageratinae) from Bahia, Brazil

Two new species of Acritopappus, A. catolesensis D. J. N. Hind & Bautista and A. pintoi Bautista & D. J. N. Hind from the Chapada Diamantina, Bahia State, Brazil, are described and illustrated. The genus is predominantly from the campos rupestres of Bahia and Minas Gerais States, and 15 species are now recognized in Bahia. The first new species, because of its typical monopodial primary axis and decussate side branches and inflorescences, falls into a group of non-viscid leaved species. The second species, unique in the genus, is a distinctive tree, and has unusual leaf and inflorescence characters. The tree-like nature of the species in the genus is discussed relative to the terminology usually applied to many members of the Compositae found in Brazil.

Andropogoneae Evolution and Generic Limits in Sorghum (Poaceae) Using ndhF Sequences

DNA sequences of the chloroplast gene ndhF were used to estimate the phylogeny of the grass tribe Andropogoneae. Previous hypotheses of relationships in the tribe were based on cytological and mor- phological characters such as the presence/absence of awns, monoecy vs. andromonoecy, or inflorescence characteristics. Classifications were subsequently proposed based on those ideas of relationships, and these are examined in the context of the molecular data. The notion that the base number of the tribe is x=5 is tested using the phylogeny. Diploids with n=5 are not conclusively the earliest diverging members of the group but are nested high in the tree and the earliest diverging lineages in the tribe have n=10. Subtribal designations are not informative due to the lack of resolution between clades in the strict consensus tree. There are well-supported clades in the tribe, including three Sorghum lineages and a core Andropogoneae clade, even though relationships among clades are poorly supported. The topological pattern suggests a rapid radiation for the group. A preliminary assessment of the generic limits of the genus Sorghum show it to be paraphyletic, including the genera Cleistachne, Miscanthus, and a species of Microstegium. Subtribe Sorghinae is represented here by Sorghum, Sorghastrum, Cleistachne, Bothriochloa, Capillipedium, Dichanthium, and Chry- sopogon and does not form a monophyletic group.

Cutflower characteristics of terminal flowering tropical Grevillea: a brief review

Summary. The large and colourful cut inflorescences of the terminal flowering tropical Grevillea species and hybrids are considered by enthusiasts to have potential as a cutflower crop. Developing understanding of the characteristics of grevillea inflorescences is collated in this review article. Botany, quality, cultivars, production and marketing, physiology and biochemistry, growth and development, flowering regulation, senescence, postharvest losses, pests and diseases, loss reduction measures, and use of floral preservatives for cut inflorescences are discussed. This overview of current knowledge provides a platform for future research and development on this novel native Australian flower.

Genetic control of branching pattern and floral identity during Petunia inflorescence development.

A main determinant of inflorescence architecture is the site where floral meristems are initiated. We show that in wild-type Petunia bifurcation of the inflorescence meristem yields two meristems of approximately equal size. One terminates into a floral meristem and the other maintains its inflorescence identity. By random transposon mutagenesis we have generated two mutants in which the architecture of the inflorescence is altered. In the extra petals- (exp) mutant the inflorescence terminates with the formation of a single terminal flower. Phenotypic analysis showed that exp is required for the bifurcation of inflorescence meristems. In contrast, the aberrant leaf and flower- (alf) mutant is affected in the specification of floral meristem identity while the branching pattern of the inflorescence remains unaltered. A weak alf allele was identified that, after bifurcation of the inflorescence meristem, yields a 'floral' meristem with partial inflorescence characteristics. By analysing independent transposon dTph1 insertion alleles we show that the alf locus encodes the Petunia FLORICAULA/LEAFY homolog. In situ hybridisation shows that alf is expressed in the floral meristem and also in the vegetative meristem. Differences and similarities between these Petunia mutants and mutations affecting inflorescence architecture in other species will be discussed.

A New Species of Metroxylon (Arecaceae) from Western Samoa

Metroxylon paulcoxii sp. nov., from the islands of 'Upolu and Savai'i in Western Samoa, is described, illustrated, and compared to M. warburgii (F. Heim) Beccari, which is also present in Samoa. Metroxylon paulcoxii is differentiated from M. warburgii by the presence of three autapomorphic characters: shorter mid-rachis leaflets, pendulous or variable rachillae, and terminal (distal) rachillae more than twice as long as lateral (proximal) rachillae. In addition, the ambiguous name M. upoluense Beccari is discussed. While surveying the palms of Samoa in 1996 with Scott Zona of Fairchild Tropical Garden, Miami, specimens of Metroxylon warburgii (F. Heim) Beccari were collected from the islands of 'Upolu and Savai'i in Western Samoa. During the course of collecting, Samoan colleagues and guides indicated that two entities existed. Further discussions with elderly Samoans confirmed that two ethnovarieties (culturally recognized taxa) of Metroxylon traditionally were recognized and collectively called niu Lotuma. Although recognized by some informants, the two ethnovarieties do not appear to have separate Samoan names. The leaves of the trees are used by Samoans as leaf thatch, and recently some individuals have learned that the stem pith can be used as a source of edible starch. Some informants indicated that the leaves of one of the two ethnovarieties were not useful for thatch. Throughout both islands, we encountered and collected herbarium specimens from isolated and mixed stands of both ethnovarieties, which appear to be sympatrically and sym-ecologically distributed. Detailed taxonomic studies, as outlined below, support the conclusion that the two entities are specifically distinct, one representing the widely distributed Metroxylon warburgii, and the other a Samoan endemic, here described as Metroxylon paulcoxii. Morphological variation in the species ofMetroxylon sect. Coelococcus has been previously considered (McClatchey, 1996), with recognition of wide variation in many vegetative and fruit characters. Much less infrataxon variation has been observed in floral and inflorescence characters. Characters observed in the field varied much more widely than those observed on herbarium specimens; therefore this research has relied more heavily upon field observations of living trees than only upon preserved materials. Previous analysis of morphological variation among populations of species of section Coelococcus (McClatchey, 1996) has supported the phenetic distinction of each species. These phenetic species were then used in a morphological cladistic analysis that provided a hypothesis that M. paulcoxii is more closely related to M. warburgii than to the other species of section Coelococcus (M. amicarum (H. Wendland) Beccari, M. salomonense, and M. vitiense). Only characters that consistently differentiate M. paulcoxii and M. warburgii (Table 1) have been selected for this discussion, although many more have been used in historical descriptions of the species of Metroxylon (Beccari, 1918). A brief synopsis of the historical record of taxonomic studies of Metroxylon in Samoa is provided below. METROXYLON UPOLUENSE BECCARI, NOMEN DUBIUM In 1905, the German botanist Rechinger sent sp cimens of apparently immature Metroxylon f uits from the island of 'Upolu, in Samoa, to Beccari in Italy, which were subsequently named M. upoluense Beccari. The author located these fruits in FI still in the original envelope that was used to mail them from Samoa. These fruits are pyriform in shape, as are fruits of M. warburgii and M. paulcoxii, as well as some fruits of M. amicarum. Beccari's (1918) description of M. upoluense is simply a description of immature pyriform Metroxylon fruits, which are unassignable to species. These m y represent either M. warburgii, which had previously been described, or M. paulcoxii, which is ein described. It is also possible that the immature fruits represent M. amicarum, but this is improbable because this species is found in Micronesia, far to the northwest of Samoa. Thus the name M. upoluense Beccari, which has a type and description that cannot with confidence be determined [WESTERN SAMOA. 'Upolu Island: 1905, Rechinger s.n. (FI), Asiatic Palms-Lepidocaryeae Ann. Roy. Bot. Gard. (Calcutta) 12(2): 156-195. 1918] is considered to be a nomen ambiguum. NovoN 8: 252-258. 1998. This content downloaded from 157.55.39.58 on Wed, 16 Nov 2016 04:33:15 UTC All use subject to http://about.jstor.org/terms Volume 8, Number 3 McClatchey 253 1998 Metroxylon paulcoxii from Western Samoa

A New Combination in Melanthium L. (Liliaceae)

The new combination Melanthium woodii (Robbins Wood) Bodkin, made but not effectively published my doctoral dissertation, is here validated anticipation of its use the forthcoming account of the genus Flora of North America. Melanthium L. (Liliaceae) is a genus of perhaps eight species, four of them found North America from central Iowa eastward to southern New York, south to northern Florida and eastern Texas; the other four are found southwest China. The type species, M. virginicum L., occurs over this entire range, commonly swamps, marshes, and bogs. Melanthium latifolium Desrousseaux, found mostly on rich wooded slopes, and M. parviflorum (Michaux) Watson, of higher elevations, occur mainly the mid-Appalachian mountains. Another species, recognized previously as Veratrum woodii Robbins and here transferred to Melanthium, is known only from rich deciduous slopes of the Ozark Plateau, where it is rare, and from five small disjunct populations North Carolina, Georgia, and Florida. In my revision of Melanthium (Bodkin, 1978), I maintained this genus as distinct from Veratrum L. on the basis of leaf size and shape, inflorescence characters, features of the tepal glands and claws, adnation of stamens to tepals, and general habit of the plants. According to these criteria, the species heretofore recognized as Veratrum woodii belongs with the other species of Melanthium. In anticipation of its use my forthcoming account of Melanthium Flora of North America, the new combination, made but not effectively published my 1978 work, is here validated. Melanthium woodii (Robbins Wood) Bodkin, comb. nov. Basionym: Veratrum woodii Robbins Wood, Class-book bot. ed. 2, 557. 1847. TYPE: U.S.A. Indiana: Greene Co., deep woods, July, s.n. (holotype, GH). Veratrum intermedium Chapman, Fl. S. U.S. 489. 1860. SYNTYPES: U.S.A. Florida: Gadsden Co.: rich, shady hummocks, 1835, Chapman s.n. (lectotype, here designated, GH); U.S.A. Florida: s.l., s.d., Chapman s.n. (probable type, GH). When published the name Veratrum woodii and the accompanying description, he cited Robbins as author. There has been some confusion as to whether Robbins should be cited in Wood or ex There is no indication or acknowledgment that Robbins actually wrote the description, so the correct citation is Robbins Wood. The description is thorough and agrees all characters with the type at GH. Acknowledgments. I deeply appreciate the assistance given by James Reveal, University of Maryland, and Robert Kiger, Hunt Institute, the preparation of my revision of North American Melanthium.

Taxonomy of the Carex straminea complex (Cyperaceae)

The Carex straminea complex (section Ovales) consists of five species limited to hydric communities of eastern North America. Based upon gross morphology and perigynium structure, these species are closely aligned with the Carex albolutescens complex but not the western species Carex feta. An SEM investigation of the micromorphology of achene and style epidermis from 15 species of Carex section Ovales demonstrated much interspecific variation. As a result, these data could not confirm the relationship between the C. straminea complex and the C. albolutescens complex but did support the delimitation of section Ovales. Numerical analysis showed that characters of the inflorescence and perigynium are satisfactory for separating C. straminea from Carex hormathodes, a species limited to the Atlantic coast. Likewise, characters of inflorescence, pistillate scale, and perigynium could clearly separate the geographically widespread Carex alata from the Florida endemic species Carex vexans. A fifth and relatively distinctive species, Carex suberecta, was found to have a narrow ecological preference for fens and a distribution limited to the upper Midwest, with outlying populations in western Virginia. Putative natural hybrids are documented between Carex scoparia and Carex longii and some species in the C. straminea complex. Key words: Carex, Cyperaceae, section Ovales, taxonomy, SEM, biogeography, hybrid.

Carpological diversity of African Peucedanum s.l. (Umbelliferae) I. The species of southern Africa

AbstractThe anatomical structure of the fruits of 48 African species of Peucedanum s.l. and related genera Lefebvrea, Physotrichia and Steganotaenia has been studied. The fruits have been described for 23 diagnostic characters. Carpo‐anatomical structure in the species investigated has appeared to be rather variable in spite of being comparatively similar in outer mericarp morphology. The peculiarities in secretory system, structure of marginal winged ribs, as well as thickness and histological structure of pericarp are the most valuable diagnostic features. Eleven carpological groups have been separated; six of them, containing the species distributed exclusively or mainly in southern Africa, are described in the present paper. Only a small group of six species is similar to the type of Eurasian sect. Peucedanum, however these African species differ from typical species of Peucedanum in vegetative morphology and in inflorescence characters. The results obtained show the necessity of taxonomic revision in African species of Peucedanum.

Differential response of buddleia ( Buddleia davidii Franch.) to ozone

Five cultivars of buddleia, Buddleia davidii Franch., were exposed to sub-ambient, ambient, and twice-ambient levels of ozone in open-top chambers for 8 weeks (June–August) during 1995: Plants were evaluated for foliar injury, growth index, and inflorescence characteristics during and following exposure. Destructive harvests were conducted at the end of the exposure period to determine dry weights of both above- and below-ground plant components. All cultivars had symptoms of visible injury in the twice-ambient treatment at both three and eight weeks after exposures began. No visible symptoms were observed at ambient ozone concentrations. At three weeks of exposure, ‘Pink Delight’ had the highest percentage of the leaves injured (PLI), 46.2%, followed by ‘Opera’ with a PLI of 23.3%. The other three cultivars had similar PLIs of less than 15%. After eight weeks of exposure, visible injury was equally severe on all cultivars with a mean PLI of 50.2% and mean Horsfall-Barratt rating of 5.4, indicating 12 to 25% of the leaf area was injured. No ozone × cultivar interaction was found for any growth variable measured. Across cultivars, growth index was reduced by 6%, total dry weight by 35%, and the number of developing floral buds and inflorescences by 29% for plants in twice-ambient ozone concentrations compared to ambient ozone concentrations. Percent biomass allocated to inflorescences was significantly greater for plants exposed to sub-ambient levels compared to those exposed to ozone at either ambient or twice-ambient concentrations. Results indicate that ozone levels similar to those in large urban areas in the southeastern United States have the potential to reduce growth and flowering of this important landscape plant.

Evaluation of sugarcane morphological descriptors using variance component analysis

Genotypic, environmental, interaction, and error variances were studied for each of 24 qualitative and 142 quantitative morphological characters. Data were collected in 3 character sets: vegetative macromorphological, inflorescence, and epidermal. Broad-sense heritability was estimated for quantitative characters, and variance components were estimated. Non-zero significance was determined for variance components of all characters. Many characters were identified as having a large genetic component to their variation. Optimising the descriptive power of vegetative macromorphology characters requires the use of test clones to quantify the environmental effect, and a high level of sampling to reduce error variance. Less work is required for inflorescence characters, which are mostly highly heritable. Some valuable epidermal characters were identified.

Polyaxial development in homeotic flowers of three begonia cultivars

Development of staminate flowers in double-flowering Begonia semperflorens-cultorum cultivars 'Cinderella', 'Goldie Locks', and 'Lucy Lockett' was examined using epi-illumination microscopy, focussing on later stages when secondary partial floral buds formed on the floral apex. This process, switching from floral to inflorescence-like development, is an example of homeosis, the expression of inflorescence features on a floral apex. Floral development began as in a normal begonia flower with the formation of a perianth consisting of two sepals and two petals, but sepaloid and (or) petaloid appendages then developed in what corresponded to stamen positions in normal Begonia species. This was usually followed by lateral elongation, distortion of the primary floral apex, and formation of secondary partial floral buds. The pattern of primordial inception on the secondary apices tended to be irregular, but in some cases, appendage primordia formed in groups of twos, threes, and fours, and in a somewhat alternating formation on the apices. Often, primordial initiation seemed to continue on secondary apices even after anthesis of the staminate flower. Appendage primordia that formed on the secondary buds usually were laterally elongate and bifacial, giving them a phyllomic appearance. Others were, on occasion, more hemispherical at inception, but as they developed they became phyllomic. Key words: homeosis, polyaxial, floral development, intermediate inflorescence.

OZONE SENSITIVITY OF BUDDLEIA CULTIVARS

Five cultivars of buddleia, Buddleia davidii, were exposed to subambient, ambient, and twice-ambient levels of ozone in open-top chambers for 8 weeks during 1995. Plants were evaluated for foliar injury, growth index, and inflorescence characteristics during and following the exposure period. Destructive harvests were conducted at the end of the exposure period to determine the dry weight of both above- and below-ground plant components. All cultivars showed signs of visible injury in the twice-ambient treatment at both 3 and 8 weeks after treatment initiation (WAT). At 3 WAT, `Pink Delight' was the most severely injured, followed by `Opera'. The other three cultivars had similar lower levels of foliar injury. Reductions in growth index as well as dry weight were found for all cultivars in the twice-ambient treatment. The number of developing floral buds and inflorescences was reduced in the twice-ambient treatment for all cultivars. Differences among the cultivars was due to normal differences in growth habit and not due to elevated ozone levels. These data indicate that Buddleia cultivars are sensitive to levels of ozone similar to those found in urban areas of the southeastern United States.