Tall Flowering Research Articles

Soil–Plant–Pollinator Relationships in Urban Grass and Meadow Habitats: Competing Benefits and Demands of Tall Flowering Plants on Soil and Pollinator Diversity

Urban green spaces can be important habitats for soil, plant, and pollinator diversity and the complementary ecosystem functions they confer. Most studies tend to investigate the relationships between plant diversity with either soil or pollinator diversity, but establishing their relationship across habitat types could be important for optimising ecosystem service provision via alternative management (for instance, urban meadows in place of short amenity grass). Here, we investigate soil–plant–pollinator relationships across urban grass and meadow habitats through a range of measured biodiversity (soil mesofauna and macrofauna, plants, aboveground invertebrates, and pollinators) and edaphic variables. We found significant effects of habitat type on available nutrients (plant and soil C:N ratios) but less clear relationships were observed between habitat type and diversity metrics. Soil–plant–pollinator interactions across habitat types and sites showed an interconnection, whereby flowering plant abundance increased alongside soil macrofauna abundance. Site characteristics that showed strong effects on plant and invertebrate diversity metrics were C:N ratios (plant and soil) and soil pH, suggesting a potential role of nutrient availability on soil–plant–pollinator associations. Our results suggest that a combination of short-mown grass, tall grass, and sown flowers can provide greater benefits for soil and pollination services as each habitat type benefits different taxa due to differing sensitivities to management practices. For example, pollinators benefit from sown flowers but soil fauna are sensitive to annual sowing. Our results also indicate that sown flowers may not optimise overall biodiversity as expected due to disturbance and the depleting role of tall, flowering plants on soil nutrient availability. Future research across a greater range of sites in urban landscapes would resolve the potential role of nutrient availability in modulating soil–plant–pollinator interactions in urban green spaces.

PROSPECTS FOR GROWING PLANTS OF THE GENUS EUSTOMA L. IN PROTECTED GROUND

The article presents the results of studies on the cultivation of Eustoma L. plants in closed ground conditions on different substrates. As a result of the cultivation, the influence of the substrate on the passage of the main phenological phases of plant growth and development was determined, as well as data on the effect on plant height and flower diameter of different varieties. Four substrates were used in the study, namely: Domoflor; Compo; Peatfield; Generous soil and seven varieties of the genus Eustoma were studied: Aurora, Echo, Heidi, Flamenco, Mermaid, LittleBell, Florida Pink. It was found that growing plants of Eystoma L. varieties on substrates increases the duration of flowering from 3.39 % to 8.96 %, and accelerates flowering by several days. The size of the flower is a characteristic feature of the Eustoma species. The larger the flower size, the better the growing conditions. Most Eustoma varieties are characterized by the formation of flowers with a relatively large diameter. As a result of growing Echo and Florida Pink varieties, the flower diameter was the smallest and amounted to only 5 cm and was 3 cm or 37% less than the flower diameter of Aurora. A slight increase in flower diameter, relative to Echo and Florida Pink, but less than Aurora, was found for Echo, Heidi, Mermaid and LittleBell. In these variants, the flower diameter was at the level of 6-7 cm. The large size of the flower and similar diameter relative to the control was characterized by the variety Flamenco. The flower diameter of this variety was 8 cm. The use of the Compo substrate for growing tall flowers gave the highest plant height of 98 cm (+18.8 %), and in the case of short flowers 15.3 cm (+15 %) relative to the substrates: Domoflor – 89.5 cm (+8.5 %) for tall varieties and 14.3 cm (+7.5 %) for short varieties, Peatfield – 91.2 cm (+10.6 %) for tall varieties and 14.3 cm (+7.5 %) for short varieties, and on the substrate Generous Earth the plant height was 88 cm (+6.6 %) for tall flowers and 14.3 cm (+7.5 %) for short varieties. Experiments have shown that the substrate does not have a significant effect on flower diameter, with the exception of the Compo. In this variant, an increase of +2.1 % was found in the overall study, while in other substrates the indicator increased only by +0.76 %. Despite the different plant heights, the number of peduncles and buds on the experimental plants was almost the same. Their total number was in the range of 25-34 pcs. The largest number of buds was characterized by the varieties Eustoma, Echo and Heidi. In these variants, the total number of buds was 33 pcs. The same number of buds was characterized by the varieties Flamenco, Mermaid and Little Bell. As a result of growing the Florida Pink variety, the number of buds was the smallest and amounted to only 25 pcs. In terms of substrate use, the best performance was characterized by the Compo substrate, which on average had 1 more bud than the control (+3.5 %), while other substrates had slightly lower rates of increase in the number of buds, where their value ranged from (1-2 %).

PROSPECTS OF CULTIVATION OF SPECIES OF THE GENUS EUSTOMA L. IN CLOSED SOIL BY CUT

The article presents the results of research on the cultivation of Eustoma L. plants in closed soil on various substrates. As a result of cultivation, their influence on the passage of the main phenological phases of plant growth and development was established, and data on the effect of substrates on plant height and flower diameter of different varieties were also given. Four substrates were used in the study, namely: Domoflor; Compo; Peatfield; Generous land and studied seven varieties of Eustoma: Aurora, Echo, Heidi, Flamenco, Mermaid, LittleBell, Florida Pink. It was established that growing Eystoma L. plants on substrates increases the duration of flowering from 3.39% to 8.96%, and accelerates flowering by several days. Flower size is a characteristic feature of Eustoma species. The larger its size, the more optimal are the growing conditions. Most varieties of Eustoma were characterized by the formation of flowers with a relatively large diameter. As a result of growing the Echo and Florida Pink varieties, the diameter of the flower was the smallest and was only 5 cm, which was inferior to the diameter of the flower of the Aurora variety by 3 cm, or by 37%. Insignificant increase in flower diameter relative to the Echo and Florida Pink varieties, but smaller than the Aurora variety, was found in the Echo, Heidi, Mermaid and LittleBell varieties. In the indicated variants, the flower diameter was at the level of 6-7 cm. The Flamenco variety was characterized by a large flower size and a similar diameter relative to the control. The flower diameter of this variety was 8 cm. The use of the Compo substrate for growing tall flowers gave the highest plant height indicator, which was 98 cm (+18.8%), and in low plants 15.3 cm (+15%) compared to the substrates: Domoflor - 89.5 cm (+8, 5 %) for tall varieties and 14.3 cm (+7.5 %) for short varieties, Peatfield - 91.2 cm (+10.6 %) for tall varieties and 14.3 cm (+7.5 %) for low-growing varieties, and on the Shchedra Zemlya substrate, the plant height index was 88 cm (+6.6%) for tall flowers and 14.3 cm (+7.5%) for low-growing varieties. Experiments have established that the substrate does not have a significant effect on the diameter of the flower, with the exception of the Compo substrate. In the specified variant, in general, an increase of the investigated indicator was established by +2.1%, in other substrates, the indicator increased only by +0.76%. Despite the different plant heights, the number of peduncles and buds on the recorded plants was almost the same. Their total number was in the range of 25-34 pcs. Eustoma Echo and Heidi varieties were characterized by the largest number of buds. In these variants, the total number of buds was 33 pcs. Flamenco, Mermaid and LittleBell varieties were characterized by the same number of buds. As a result of the cultivation of Floridfa Pink variety, the number of buds was the smallest and amounted to only 25 pcs. For the use of substrates, the Compo substrate was characterized by the best indicators, in which, on average, 1 more bud was established on the plants than in the control (+3.5%), other substrates had slightly lower indicators of an increase in the number of buds, where their value ranged from (1- 2%).

Effects of a Gibberellin Inhibitor on Flowering, Vegetative Propagation, and Production of Rapid Generation Cycling Gladiolus for Potted Plant Production

Gladiolus (Gladiolus ×hybridus) is an asexually propagated, herbaceous perennial and an economically important cut flower crop. In commercial production, gladioli have tall flower stalks, which limit their use to cut flowers and annual garden plants. The gladiolus breeding program at the University of Minnesota has bred and selected rapid generation cycling (RGC) cycle 1 gladiolus, which can flower in <1 year from seed instead of the norm of 3 to 5 years (which are vegetatively propagated as corms). Gibberellin inhibitors, such as ancymidol, are used as plant growth retardants to control height in potted plants. Higher concentrations can inhibit flowering along with other negative side effects. The aim of this study was to investigate the growth, flowering, and corm/cormel production response of cycle 1 gladiolus to the gibberellin inhibitor, ancymidol (0, 100, and 400 mg·L−1 soak) in comparison with noncycle 1 genotypes and commercial cultivars for potted gladiolus production. Cycle 1 genotypes flowered with all ancymidol concentrations while noncycle 1 genotypes had significantly fewer flowers or were completely nonflowering under higher concentrations. All tested genotypes had increased leaf width as ancymidol concentration increased. Conversely, flower stalk heights were shorter as the ancymidol concentration increased while the number of stalks was nonsignificant. Corms, cormel number, and fresh weights decreased in all genotypes except for one cycle 1 genotype, which had an increase in both corm number and fresh weight when treated with 100 mg·L−1 ancymidol. Cycle 1 gladiolus are more resilient to this gibberellin inhibitor even at high concentrations and can potentially be used for gladiolus potted plant production.

United Arab Emirates: Adnoc Refining – carbon black

In this study functional micromorphological traits and water repellent attributes of floral and leaf surfaces of Asphodelus ramosus are presented. The branched inflorescences of A. ramosus bear numerous short-lived flowers arranged on tall flowering stalks, while the basal long-tapered leaves are long-lived. The most striking feature of the short-lived flowers of A. ramosus is the surface structure of the coloured midrib and the white bilateral sections of tepals, revealing different functionality between the two sections of tepals and the two sides of the corollas. Structural features of adaxial and abaxial epidermal cells may function predominantly for water repellence of floral tissues expanded during the humid period of the year. The leaves are more water repellent than the tepals and display declining water retention on their surfaces. It appears that micro- and nano-scale patterns observed on leaf and tepal surfaces of A. ramosus are linked to hydrophobic properties, which are important adaptive traits contributing to the seasonal performance of A. ramosus in the field, particularly in regard to water adhesion.

Functional traits of floral and leaf surfaces of the early spring flowering Asphodelus ramosus in the Mediterranean region

In this study functional micromorphological traits and water repellent attributes of floral and leaf surfaces of Asphodelus ramosus are presented. The branched inflorescences of A. ramosus bear numerous short-lived flowers arranged on tall flowering stalks, while the basal long-tapered leaves are long-lived. The most striking feature of the short-lived flowers of A. ramosus is the surface structure of the coloured midrib and the white bilateral sections of tepals, revealing different functionality between the two sections of tepals and the two sides of the corollas. Structural features of adaxial and abaxial epidermal cells may function predominantly for water repellence of floral tissues expanded during the humid period of the year. The leaves are more water repellent than the tepals and display declining water retention on their surfaces. It appears that micro- and nano-scale patterns observed on leaf and tepal surfaces of A. ramosus are linked to hydrophobic properties, which are important adaptive traits contributing to the seasonal performance of A. ramosus in the field, particularly in regard to water adhesion.

First Report of Fusarium oxysporum Causing a Vascular Wilt of Statice (Limonium sinuatum) in the U.K.

Statice (Limonium sinuatum) is grown commercially in many countries as a cut-flower crop. Fungal and oomycete pathogens reported for this plant include Colletotrichum, Botrytis, Cercospora, Rhizoctonia, and Peronospora (Moorman 2016). In the UK, 80% of all statice production (2.5 ha, value $800,000) is through a specialist grower in Lincolnshire. In 2016, 30% of the 70,000 statice plants raised at this nursery were affected by a vascular wilt. Symptoms observed on approximately 1 m tall flowering plants (cv. Velvet Wings) consisted of wilted leaves and flower stalks, often progressing down one side of the stem, followed by leaf necrosis and plant death. Brown staining of vascular tissue was observed in dissected stems and, in advanced infections, mycelium was evident at the stem base. Isolations were carried out from 18 plants by excising 2 to 3 cm sections of infected stem, surface disinfecting in 5% sodium hypochlorite for 2 min, rinsing in sterile water and plating on potato dextrose agar (PDA) containing 20 µg/ml chlortetracycline. After incubation at 20°C for 4 days under natural light, fungal colonies were sub-cultured onto PDA and grown for a further 10 days. Cultures displayed morphology typical of Fusarium species, with a peach/pale pink color. Macroconidia were 3-septate, straight or slightly curved, 16.1 to 25.7 µm x 2.8 to 5.4 µm. Microconidia were abundant, elliptical or reniform, 6.1 to 12.4 µm x 1.6 to 4.9 µm. DNA was extracted from four isolates, and the translation elongation factor 1-α (EF1-α) gene amplified by PCR and sequenced using exTEF-F/ FUexTEF-R primers (Taylor et al. 2016). All isolates shared identical EF1-α sequences (GenBank accession number KX822794) and were confirmed as Fusarium oxysporum using BLAST analysis. The sequences were 99% identical to the EF1- α sequences of a wide range of F. oxysporum isolates with the greatest homology to F. oxysporum f. sp. freesia (KP964900, 99.7% over 989 bp). To confirm pathogenicity, statice (cv. Velvet Wings) plants produced by tissue culture were raised in pots. Once the first flower stalk reached approximately 30 cm, plants were removed, the bottom third of the root system excised and the remaining roots soaked in a conidial suspension (1 x 106 conidia/ml) for 5 min. As a negative control treatment, F. oxysporum isolate Fo47, a biocontrol strain known to be non-pathogenic on a range of hosts (Aime et al. 2013), was used to inoculate plants in the same way, while noninoculated control plants were soaked in sterile water. All statice (six plants / isolate or control treatment) were then replanted in compost and pots placed in a randomized design in a temperature controlled glasshouse (25°C day, 18°C night, 16 hour photoperiod). After 20 days, typical wilt symptoms were observed in all the plants inoculated with the four F. oxysporum isolates from statice, and after 40 days all the plants were dead (e-Xtra). All noninoculated control plants and those inoculated with F. oxysporum isolate Fo47 remained healthy. The pathogen was successfully re-isolated from infected stems with the fungal cultures exhibiting the same morphology as described previously. Furthermore, following DNA extraction, amplification and sequencing of the EF1-α gene of the re-isolated fungi, all sequences were 100% identical to those obtained for the original isolates, thus fulfilling Koch’s postulates. To our knowledge, this is the first report of Fusarium wilt of statice. Further work is required to establish the host range of this potentially new forma specialis.

Snail & Worm: Three Stories about Two Friends by T. Kügler

Kügler, Tina. Snail & Worm: Three Stories about Two Friends. Houghton Mifflin Harcourt, 2016.Author, illustrator, and perhaps the friend of snails and worms in her backyard, Tina Kügler introduces readers to this hilarious book with three little stories of two best friends—a lovely Snail with a droll sense of humor and imagination, and a friendly Worm with a generous heart. In the first story, when Snail joyously plays with the rock, Bob, and the stick, Ann, we can see our lovely and naïve toddlers, and even our inner child. In the next story, when Worm warmly encourages Snail to climb to the top of a tall flower, we can recall how our families, teachers, and friends firmly support us even when we do silly things. And finally, when Snail and Worm have the interesting conversation about their pets, no one can refuse but smile sentimentally. They are not invertebrates anymore, but are as lively as our children, our friends, and ourselves.The dialogic text as well as the storyboard-style illustration adds a flavour of children’s comic-strip to this picture book. The fresh yet soft colour of the drawings creates a snug feeling like spring for readers. Its funny plot, vivid illustrations, and simple vocabulary will definitely be loved by pre-school and kindergarten children. The text and the illustrations are perfectly married with each other. The hilarious dialogues can be easily memorized by young students and even pre-readers, but would also fit well for a drama performance in the classroom.This book will make you giggle with your toddlers or even with your adult family and friends; I can’t wait to read more Snail & Worm adventures!Highly Recommended: 4 out of 4 starsReviewer: Jing JinJing Jin is a doctoral student at University of Alberta, studying and working in the fields of language and literacy in elementary education. She received her M.A. degree in children’s literature from Ocean University of China, and her M.Ed. degree from the University of Saskatchewan. Her master’s thesis is a comparative study of selected award-winning Canadian and Chinese children’s picture books.

Impatiens kanchigandhiana, a new name for Impatiens nasuta H.Perrier (Balsaminaceae)

The genus Impatiens Linnaeus (1753: 937) is distributed mostly in the tropical and subtropical regions of the Old World as well as in the northern temperate regions with more than 1,000 species (Janssens et al. 2006, Jyosna & Janarthanam 2011). During the taxonomic study of the genus Impatiens in India (Gogoi & Borah 2015, Gogoi & Arisdason 2016, Gogoi et al. 2016), we find that the name Impatiens nasuta Perrier de la Bâthie (1949: 14), a species native to Tsaratanana hills of Madagascar, is a later homonym of Impatiens nasuta Hooker (1908: 263) from China. Impatiens nasuta H.Perrier differs from I. nasuta Hook.f. in its smaller, suberect, less than 30 cm tall habit, leaves elliptic, smaller, coriaceous and flowers without an annular spur. According to the Arts. 6.11, 53.1 of the ICN (McNeill et al. 2012), a new name is proposed here for the later homonym Impatiens nasuta H.Perrier.

SucculentandXeromorphic BromeliadsofBrazil

T h e m o s t widespread xerophytic bromeliads in Brazil belong to the genera D y c k i a , Or­th­­o­­ph­­ytum and En­ch­­o­­­ lir­ium. The latter, difficult to distinguish from Dyckia, is probably unfamiliar to succulentists. Aside from having terminal flower stalks, all species of En­ch­­o­­lir­ium are native to Eastern Brazil, with some ranging into the more central areas. In contrast, Dyckia, which never flowers terminally, prefers the more central and western parts of the country. With this installment we present a rare En­ch­­o­­lir­ium species that has a 4 m tall inflorescence and yellow flowers. In part two of this series we discussed Or­th­­o­­ph­­ytum h­­o­­r­r­idum, a grayish-white representative of the genus from Minas Gerais. Or­th­­o­­ph­­ytum bur­le­ mar­xii from Bahia has less spectacular leaves, but the inflorescences are impressive and highly ornamental. Here we discuss its history, entwined with the life of garden architect and plant explorer, Roberto Burle-Marx, which makes the plant all the more interesting. Dyckia go­­eh­­r­in­gii is a succulent bromeliad from Mato Grosso discovered by Eddie almost three decades ago but then more or less lost due to a mistake in the original description. We hope our account will alleviate some confusion and widen the appeal of these xerophytic bromeliads in succulent horticulture. Succulent and Xeromorphic Bromeliads of Brazil Part 3 Encholirium maximum, Orthophytum burle-marxii & Dyckia goehringii

Effect of individual height and labellum colour on the pollination of Caladenia (syn. Arachnorchis) behrii (Orchidaceae) in the northern Adelaide region, South Australia

Caladenia behrii, a sexually deceptive orchid, is an endangered terrestrial orchid endemic to the Adelaide Hills, South Australia. We examined pollination success among individuals of different colours and heights in three populations of C. behrii in the northern Adelaide region. The labellum of C. behrii varies from cream to deep maroon. Over five years, the pollination success (pollinia deposited on stigma) of four colour groups (maroon, maroon and cream, hatched, and cream) was assessed for a total of 782 flowers. Labellum colour had no effect on the pollination success of individuals, indicating no frequency-dependent selection. It is likely that pollinators use the sexual pheromone mimic produced by the flowers as the main orientation cue. For three years the height of pollinated C. behrii individuals was recorded, along with the height of the nearest non-pollinated neighbour (distance of labellum from the ground, rather than stem length). Although a range of different heights was pollinated at population level, individual flowers that were taller than their closest neighbours were significantly more likely to be pollinated. Flower head height was not correlated with opening date and was greater for orchids growing among grass-tree leaves. Results imply that pollinators are more successful in finding tall flowers than short ones for visual and/or olfactory reasons; however, the effect of height preference is eliminated at population level.

Vulnerability of Tasmanian giant trees

SummaryTasmania's giant trees are among the world's tallest flowering plants and Australia's greatest eucalypts. However, they are not well protected in National Parks or extensive reserves.Of the 69 known trees that meet the official criteria for protection as giants, almost 90% are in State forests managed for wood harvesting. Several of the giants are within coupes that were scheduled for clearfelling under the Tasmanian 2004–2007 three-year wood production plan, and recent harvesting operations have threatened or killed several others.Fifty-five per cent (38) of the known Tasmanian giants, including the tallest trees, the tallest stand, the tallest stringybark, and the second most massive stringybark, exist in the middle of the Styx Valley. Harvesting and regeneration burning operations indirectly threaten most of these trees, because they stand close to scheduled or recently clearfelled coupes. More importantly, increasing the proportion of young, dense, highly flammable eucalypt regrowth forest, at the expense and fragmentation of less flammable old—growth forest, seriously exacerbates the risk of wildfire, and invites annihilation of all the Styx Valley giants.Nominal protection of individual giant trees in small (100-m radius) management decision classification zones, or stands of trees in reserves of a few hundred hectares surrounded by production forest, does not provide effective protection in the long term. Numerous historic and recent examples in Tasmania and Victoria show the failures of these well-intentioned small-scale conservation efforts. Giant tree conservation requires very long-term preservation of large areas of forest in which the frequency of wildfire is very low; it is incompatible with current Tasmanian forest harvesting and regeneration practices.The Styx Valley contains the greatest number of, and many of the finest, giants existing in Tasmania. It also has high potential to produce another generation of great trees to stimulate wonder and admiration for the next half millennium. The best plan to ensure their long-term survival is to desist from forest harvesting and regeneration by fire, and to transform the entire valley into Australia's first large reserve dedicated to giant tree conservation.

Preferences for and attitudes towards street flowers and trees in Sapporo, Japan

The benefits of street vegetation, in particular the importance of trees, for urban dwellers have been given wide attention. There is, however, a lack of research on flowers as an element of street vegetation. This paper explores preferences for various street-planting models, particularly those with different compositions of flowers, with or without trees. Eighty-one residents of Sapporo evaluated 59 photomontage simulations and answered a questionnaire concerning their attitudes to street flowers. Results revealed trees to be the factor with the greatest influence on preference. Among possible elements for the space beneath trees from a choice including soil, grass, hedge and flowers, flowers were the most favoured. In particular, low and ordered compositions of brightly coloured flowers were the most preferred. Tall flowers were not found to be either attractive or appropriate for streetscapes in this case study. A factor analysis of the variables related to attitudes towards street flowers revealed the following five factors: “psychological benefits and aesthetic value”, “natural–environmental”, “practical concerns”, “effort to maintain” and “non-aesthetic”. The highest rated items were all related to the aesthetic and psychological benefits of street flowers. Flowers were the most preferred element beneath street trees and were seen as not only contributing to the aesthetic quality of a street but as also having a positive influence on psychological well-being.

The flowers of Drosanthemum Schwantes (Ruschioideae, Aizoaceae)

Summary: Based on almost 1000 collections of species of Drosanthemum, the morphology, number of elements, and the changes during anthesis of flowers have been studied. Five main types of flowers are distinguished and described here: stamen carpet flowers, tall cone flowers, low cone flowers, low column flowers, and tassel flowers. A key to the types is given. In addition, one new species is described: D. dipageae H.E.K.Hartmann.

Location and activity of hyphae of the downy mildew, Peronosclerospora noblei (Family Peronosporaceae), and its relationship to symptom expression on wild sorghum (Sorghum leiocladum)

A study of the temporal and spatial relationships between the downy mildew, Peronosclerospora noblei and its host, Sorghum leiocladum (wild sorghum) has been undertaken. Hyphae of P. noblei perennate in the tiller bases of wild sorghum when the grass is dormant over the winter months. In early summer, hyphae grow into some tiller buds but not into others. Tillers that develop from invaded buds become systemically invaded by the hyphae, in most cases remain vegetative and bear the anamorph and teleomorph of the downy mildew. Tillers that develop from buds that are not invaded become short vegetative tillers or tall flowering tillers. On infected tillers symptom development is delayed until at least the third leaf, as a direct result of hyphal activity in the developing tiller. The location and activity of hyphae of P. noblei in tiller bases and developing tillers are responsible for the perennation of the pathogen and for the expression of symptoms in infected tillers of S. leiocladum. There may be similar relationships between hyphal location and activity and symptom development in other systemic pathogens of perennial grasses.

Transposition of flower height by bumble bee foragers (Bombus impatiens)

Honeybees learn visual characteristics of reinforced and non-reinforced flowers in differential conditioning experiments (i.e., experiments that require subjects to choose between a reinforced and non-reinforced flower). In this study bumble bee foragers (Bombus impatiens) were trained in a transposition paradigm to determine if the relational properties of flowers also influence choice behavior. Subjects in one group (group A) were trained with repeated choices between a medium-height flower replete with sucrose solution and an empty tall flower until the medium-height flower was sampled preferentially in five consecutive trials. A second group (group B) was trained on the medium height flower alone for five trials. In a single test trial subjects were given a choice between the medium-height flower and a short flower, each filled with water. A control group showed no preference in this test. Group B subjects showed a significant preference for the medium-height flower and group A subjects that exhibited flower constancy (i.e., sampled only the medium-height flower in training trials) showed an identical pattern of choice. Subjects in group A that sampled both flowers during training, in contrast, transposed flower height and preferred the short flower. These results suggest that the choice behavior of bumble bee foragers is influenced by relational and absolute properties of flowers. The flower characteristics learned by foragers appear to depend on the difficulty of the discrimination problem and the context in which flowers are sampled. Patches of flowers limited in phenotypic variability may produce simple associative learning and flower constancy by foragers.

Influence of Propagation Method and Fertilizer Rate on Growth and Development of Liatris pycnostachya

Abstract Field planting of corms of Liatris pycnostachya Michx. cv. Eureka produced superior plants for cut flower production than seeds, seedlings, or rooted stem cuttings. Corms with diameters of 2.4 to 7.9 cm produced the highest number of tall flowering stems. Transplanted seedlings produced larger corms with more buds than corms harvested from rooted stem cuttings or direct-seeded plants. Fertilizer (10N–8.6P–8.3K) applied at the rate of 3 kg/100 m2 was sufficient for producing superior quality flowering stems.

The Influence of Foliage Habit on Competition Between Carrot Plants

Carrot plants of a cultivated variety (cv. Chantenay Red Cored) and those of a wild type were grown in both pure and mixed populations in which root competition was prevented. During early growth, cultivated plants competed effectively against the wild plants. Fifty days after sowing chitted seed, the mean weight of the storage organs of the cultivated variety grown in mixed populations was 56 per cent greater than the mean weight of cultivated storage organs in a pure population. Subsequently, however, this competitive advantage diminished, this being associated with the development of tall flowering stems by the wild plants. The foliage habit of the vegetative cultivated plants was more erect than that of the vegetative wild plants. This difference in foliage habit might explain why the cultivated plants out-compete the wild plants.

Timing of Reproduction in Hymenopappus tenuifolius Pursh (Compositae), a Purported Biennial

As in many other supposed species, the life history of Hymenopappus tenuifolius is best described as short-lived and semelparous, rather than biennial. No individuals in a Texas population of H. tenuifolius successfully flowered at the age of 1.5 years, or after 2 growing seasons. Most plants did not flower until they were 2.5, 3.5, 4.5 years of age or older. Some plants at least 4.5 years old have still not flowered. Hence, H. tenuifolius is not a strict biennial, as previously described. Timing of reproduction in H. tenuifolius is more dependent on individual plant size than plant age. Plants which do flower are usually larger than individuals of the same age which do not flower. Perhaps, in order to reproduce successfully, a certain amount of energy must be available in the taproot to provide the initial investment in the tall flowering stalk characteristic of so many biennial (short-lived semelparous) plant species.

Ecotypic Differentiation within Four North American Prairie Grasses. III. Chromatographic Variation

Four widespread grasses, Andropogon scoparius Michx., A. gerardi Vitman, Sorghastrum nutans (Nash) Hitchc. and Panicum virgatum L., have been studied behaviorally and morphologically. In the present comparison characteristic flavonoid patterns were shown whereby the four grass taxa can be separated at the generic and specific level. The greatest similarity was shown by the two Andropogon species. Panicum was most dissimilar. Although intrapopulational and interpopulational variation was demonstrated within each of the four taxa, both in transplanted material and in native plants of the original transplant site, there was no decisive correlation of biochemical variation with geographic origin, vegetative characteristics or maturity pattern. Early-flowering clones with short flowering culms and glabrous leaves, originating in northern and western areas, were essentially similar biochemically to later-flowering clones with tall flowering culms and extremely pubescent leaves, originating in southeastern areas. Blade samples collected in late fall, 1963, and in early spring, 1964, from the same transplanted clones were similar in flavonoid pattern. In P. virgatum. individual clonal patterns were characteristic of ramets grown under various day-length-thermoperiod conditions. Although biochemical markers for ecotypes would be useful êological tools, partially replacing their cultivation in transplant gardens, geographically correlated patterns were not revealed in this study. However, this study supports the present systematic position of the various morphologically and behaviorally diverse populations within the four taxa.