FLOWERING RESPONSES AND PHYLOGENY IN THE PHACELIA FRANKLINII GROUP (HYDROPHYLLACEAE)

Gillett , George W. (U. Hawaii, Honolulu.) Flowering responses and phylogeny in the Phacelia franklinii group (Hydrophyllaceae). Amer. Jour. Bot. 50(8): 798–801. Illus. 1963.—Phacelia franklinii is long-day positive, with or without gibberellin, but P. sericea, P. idahoensis, P. mollis, and P. lyallii did not flower under these conditions. The latter 4 species flowered after short-day, low-temperature induction treatments. An interpretation of phylogenetic relationships, based on flowering responses, genetic compatibility, and morphological and anatomical information, is presented.     

西沙群岛草海桐的抗逆生物学特性

热带珊瑚岛由于光照强、季节性干旱明显、土壤贫瘠、保水能力差而少有植物生长。草海桐(Scaevola sericea)是一种典型的热带滨海植物,是西沙群岛珊瑚岛植被中的主要建群种,在海岛和海岸带防风固沙及植被生态恢复等方面发挥着重要作用。该研究对西沙群岛自然环境下草海桐的形态解剖学特征、抗氧化能力、抗逆性物质含量及营养元素含量等进行了研究。结果表明:草海桐具有阳生性植物特征,叶片及上表皮厚、气孔密度小、导管直径及水力导管直径大,有利于其适应珊瑚岛干旱环境; 其体内的超氧化物歧化酶和过氧化氢酶活性与其他受胁迫植物相比较要高,脱落酸含量也较高,表明草海桐对珊瑚岛环境具有较强的适应性及抗逆性; 其根际土壤养分含量偏低,但植物体内营养元素含量却较高,表明草海桐对土壤养分的利用效率高。这说明草海桐能够很好地适应干旱、贫瘠的珊瑚砂环境,具有较强的抗逆及适应能力。     

Una nueva especie de <Emphasis Type="Italic">Tibouchina</Emphasis> (Melastomataceae) del Sur de México

Tibouchina sericea, a new species of Melastomataceae from isolated pine forests of southern Mexico, is described and illustrated. This species resembles the rare T. nanifolia in the short and open pubescence of the stem, and the yellow subisomorphic anthers, but differs in the bullate leaves and the bulla-based hypanthial hairs.

---

Resumen  Se describe Tibouchina sericea, una nueva especie de Melastomataceae que se encuentra en localidades aisladas con bosques de Pinus del sur de México. Esta especie se asemeja a T. nanifolia, una especie rara, en la pubescencia corta y abierta del tallo y las anteras amarillas subisomórficas, pero difiere en las hojas abolladas y en los pelos del hipantio con la base globosa.

     

The archaeological remains of leucaena (Fabaceae) revised

Archaeological specimens of Leucaena (Fabaceae; Mimosoideae) previously published (Tamaulipas, Tehuacan Valley, and Oaxaca Valley) which are housed at the Departmento de Prehistoria, Instituto Nacional de Antropología e Historia, Mexico City, were reexamined. Selected remains from Tehuacan were observed with scanning electron microscopy and ultrastructural features were compared to material from herbarium specimens. External epidermis near margins of legume valves provided identification characteristics (stomata abundance and morphology, texture, pubescence). In Tehuacan, L. leucocephala subsp. glabrata was found in addition to two previously reported taxa—L. esculenta and L. diversifolia subsp. stenocarpa (L. pueblana). Acacia sericea, a wild tree with edible legumes, was frequently misidentified as Leucaena. In Guilá Naquitz, Oaxaca, all samples reported as L. esculenta were identified as another edible, wild legume tree, Conzatia multiflora. Chronology was assigned following published reports and, also for Tehuacan, the field catalogue. Possible use was assigned based upon evidence of chewing and insect damage, indicating ripeness of legumes. No direct evidence of cultivation was found. However, the presence of L. esculenta in Tehuacan (since ca. 4000-1000 B.C.) and of L. I. glabrata (since ca. 300 B.C.-A.D. 780) suggests their introduction there as a cultivated plant.     

Photinia taishunensis sp. nov. (Rosaceae) from Zhejiang,eastern China

Photinia taishunensis G. H. Xia, L. H. Lou & S. H. Jin (Rosaceae, Spiraeoideae) from Zhejiang, China, is described and illustrated. It has previously been confused with P. lochengensis Yü, but differs in details of habit, leaf size, leaf shape, inflorescence, flower size and pubescence. The pollen grains of P. taishunensis are monads, elliptical with trisulcate apertures, and the exine is rugulose, dotted with sparse punctures.     

Interspecific hybridization of plants and resistance to herbivores: hypotheses,genetics, and variable responses in a diverse herbivore community

We studied the morphology, molecular genetics, and hebivory of two species of willows (Salix sericea and S. eriocephala) and their interspecific hybrids to test four alternative hypotheses concerning the effects of hybridization on plant resistance. Individually marked plants were identified using morphological traits in the field and measurements of stipule and leaf pubescence were made and compared using Canonical Discriminant Function Analysis. DNA was extracted from the leaves of a sample of the marked plants and RAPD-PCR analysis was performed to establish the genetic status of parental and hybrid plants. RAPD band analysis generally verified the genetic status of parental plants. Hybrid plants were usually correctly identified in the field with a few exceptions. However, the hybrid plants were a heterogeneous group of plants made up of most plants that appear to be F₁s and a few plants that appear to be backcrosses to S. sericea. Morphological variables were useful for distinguishing S. sericea from S. eriocephala and hybrids, but were not as dependable in distinguishing between S. eriocephala and hybrids. We compared the densities of 11 herbivore species and the infection by a leaf rust pathogen (Melampsora sp.) on the leaves and stems of two parents and the hybrids in the field. We found support for the Additive hypothesis (3 species), the Dominance hypothesis (2 species) and the Hybrid Susceptibility hypothesis (7 species, 6 herbivores and the Melampsora rust). We found no evidence for the Hybrid Resistance hypothesis. Guild membership was not a good predictor of similar responses of species to hybrid versus parental plants. A Canonical Discriminant Function Analysis showed discrete separation of the taxa based on herbivore densities, illustrating different community structures on hybrid and parental plants. This study demonstrates the diversity of responses of phytophages in response to interspecific hybridization.     

Predicting pathogen-induced mortality in Hakea sericea (Proteaceae), an aggressive alien plant invader in South Africa

The woody shrub Hakea sericea is an aggressive invader of natural vegetation in South Africa. Large-scale die-back in H. sericea is attributed to a form of the fungus Colletotrichum gloeosporioides. The progression of symptoms of the disease was monitored over 21 months. Results were used to construct a transition matrix model to predict further progression of the disease. Eighty-two percent mortality is predicted after 10 years. Pathogen-induced seed release occurred mainly between October and January. No regeneration was observed beneath or near infected stands of H. sericea. The model will be useful to managers when identifying priority areas for weed control operations.     

Structure of floral galls of Byrsonima sericea (Malpighiaceae) induced by Bruggmanniella byrsonimae (Cecidomyiidae,Diptera) and their effects on host plants

Galls are anomalies in plant development from parasitic origin, and affect cellular differentiation or growth of plants. This parasite–plant interaction occurs in many environments and typically in vegetative organs of plants. The existence of galls in reproductive organs and their effects on the host plant are seldom described in the literature. In this paper, we present a novel study of galls in plants of the neotropical region. Galls of Bruggmmaniella byrsonimae develop in the flower buds of Byrsonima sericea DC. (Malpighiaceae) and affect development of the reproductive organs and the reproductive effort of these plants. The sepals and petals show hypertrophy of parenchyma tissues after differentiation, and the stamens exhibit degeneration of the sporogenic tissue. The gynoecium is not entirely developed; ovary and ovules are often absent. Changes in vascular tissues are also frequent, which may indicate high demand for nutrient resources by the new tissues initiated by the larva. We compared the amount of inflorescences, galls and fruits to evaluate possible effects on host reproduction. The results suggest that the Cecidomyiidae galls in flower organs affect fruit set and the reproductive success of B. sericea.     

栽培与野生化血丹不同部位中两种化学成分含量分析

为探讨并分析栽培与野生化血丹植株中不同部位中两种化学成分的含量差异,该研究采用超声法提取、高效液相色谱法(HPLC)测定栽培与野生化血丹根、茎、叶、花、混合样等部位中桃叶珊瑚苷和梓醇的含量,并进行比较。结果表明:(1)桃叶珊瑚苷在栽培与野生化血丹植株内均有分布,含量均以根中最高,其在栽培与野生化血丹植株内的含量表现分别为根>叶>混合样>茎>花、根>混合样>茎>花>叶,栽培化血丹不同部位中桃叶珊瑚苷的含量均高于野生化血丹。(2)梓醇在栽培化血丹的茎中未检出,在栽培与野生化血丹其他部位均有分布,含量均以叶中最高,其在栽培与野生化血丹植株内的含量分别表现为叶>花>混合样>根、叶>混合样>茎>花>根,野生化血丹不同部位中梓醇的含量均高于栽培化血丹。(3)桃叶珊瑚苷和梓醇在栽培和野生化血丹植株不同部位中的含量均存在显著差异(P<0.05),栽培与野生同一部位间总体上无显著差异,为该濒危药用植物资源药用部位选择和合理开发利用提供实验参考。     

The susceptibility of parental and hybrid willows to plant enemies under contrasting soil nutrient conditions

 We conducted an experimental study of the effects of nutrient addition on the susceptibility of two species of willows (Salix eriocephala and S. sericea) and their hybrid to a pathogen and several herbivores. We hypothesized that the relative susceptibility of parental and hybrid willows would depend upon soil nutrient availability and vary among plant enemies. Using potted plants in a common garden, we found that S. eriocephala was significantly more susceptible to attack by a fungal rust (Melampsora sp.), a leaf-chewing beetle (Popillia japonica), and a leaf-folding sawfly (Phyllocolpa nigrita) than was S. sericea. Conversely, S. sericea was significantly more susceptible to attack by a spider mite (Tetranychus sp.) and a leaf-mining caterpillar (Phyllocnistis sp.) than was S. eriocephala. Hybrid susceptibility to Melampsora sp. and to Phyllocnistis sp. resembled S. eriocephala’s, while hybrid susceptibility to Phyllocolpa nigrita, Tetranychus sp., and Popillia japonica resembled S. sericea’s. Susceptibility to a sixth enemy, another leaf-mining caterpillar, Phyllonorycter salicifoliella, did not differ among the parents and hybrid. Susceptibility to herbivores and pathogens increased along a gradient of increasing fertilizer application, and this effect was independent of plant taxon or enemy. The results of our study point to the contrasting influences of a taxonomically and functionally diverse enemy community, reinforce the hybrid dominance model of enemy susceptibility, and demonstrate that physiological stress and enemy susceptibility can be inversely related. Received: 25 March 1996 / Accepted: 6 August 1996     

广椭牛齿兰，中国兰科一新记录种

报道了在海南热带雨林国家公园内发现的兰科牛齿兰属中国一新记录种：广椭牛齿兰[Appendicula ovalis(Schltr.) J.J.Sm. ex Mansf.]。该种原分布于马来半岛、苏门答腊岛、爪哇岛、婆罗洲、苏拉威西岛,在形态上与国内记录的4种牛齿兰属植物均有较大差别,如茎中部具分枝、叶广椭圆形、单个花序仅着生1朵花、且唇瓣扭转具粉紫色斑块等特征。对产自海南的该种形态和生境进行了详细描述,并提供高清解剖照片。凭证标本保存于海南大学林学院教学标本馆(HUFB)。     

Rhus coriaria var. zebaria (Anacaridaceae), a new variety from Iraq

Rhus coriaria var. zebaria from Duhok/Aqrae, Kurdistan, Iraq is described as a variety new to science. Field expeditions started in spring 2011, continued during 2012 and 2013 with the aim of collecting sumac specimens from different physiographic regions of Kurdistan, Iraq. A total of ten plants for each variety were sampled. An equal number of tagged herbarium specimens were prepared. The holotype was designated and deposited together with other herbarium specimens in the herbarium of the Faculty of Agriculture and Forestry, Univ. of Duhok. Morphological characters of the leaf, inflorescence, flowers, infructescence, and fruit were studied. The pH value of the pericarp in addition to the hilum length was measured. Results were compared with Rhus coriaria L. var. coriaria. The most distinctive feature of the new variety is the dull whitish brown color of the drupe pericarp of var. zebaria as compared to the reddish brown color of the drupe pericarp of var. coriaria. The whitish color of the drupes of var. zebaria, in combination with their larger size, represents diagnostic characters for distinguishing this variety. In contrast, most leaf characters are of little or no taxonomic value in this species. Only shape, apex and marginal teeths of the leaflets show minor differences for separating the two varieties. Female and male inflorescences and flowers characters show no significant differences. Both hilum length and pH value characters may be useful for taxonomic application if mean values are taken in consideration.     

Characterization of a glabrate Encelia farinosa mutant: morphology,ecophysiology, and field observations

An individual Encelia farinosa (Asteraceae) from Death Valley, California is described that is completely lacking in the dense leaf pubescence covering characteristic of the species. While leaf absorptances to solar radiation of the mutant E. farinosa are much greater than those of the wild type, other morphological aspects and photosynthetic characteristics appear to be similar to those typical for E. farinosa. Leaf temperatures of mutant and wild type E. farinosa in the field are similar, but only because of steeper leaf angles and higher leaf conductances to water vapor in the mutant form. As a consequence of a greater water expenditure for transpirational cooling, the mutant E. farinosa becomes deciduous much earlier in the drought period than do the normal pubescent leaved E. farinosa.     

Herbarium survey on the genus Azolla (Salviniaceae) in Italy: distributive and taxonomic implications

An analysis of Italian herbarium specimens belonging to the genus Azolla was carried out using optical microscope and SEM techniques. According to recent international reviews, three micro-morphological characters have been considered for the specimen analysis: (i) number of leaf trichome cells, (ii) septation of glochidia and (iii) features of the macrospore perine. The analysis of the patterns concerning both vegetative and reproductive characters was complicated by the relatively low number of sporulated specimens stored in the Italian Herbaria. The analysis of the selected specimens showed the presence of two well distinct systematic groups. One group was characterized by bicellular leaf trichomes, pluriseptate glochidia and not-warty perine, traits that permitted to taxonomically attribute it to A. cristata. The second group was characterized by monocellular leaf trichomes, non-septate or uniseptate glochidia and warty perine, so that it could be taxonomically attributed to A. filiculoides Lam. This study confirmed the large use in the past of the name ‘A. caroliniana’ to indicate the species actually named A. cristata. In Italy, this species was found to be collected only in the past, while A. filiculoides was found to be present with both ancient and recent herbarium specimens.     

Aspects of the reproductive ecology of four australian Hakea species (Proteaceae) in South Africa

Summary Four shrub species of the Australian Proteaceae (Hakea sericea, H. gibbosa, H. suaveolens and H. salicifolia) were introduced to South African fynbos shrublands between 1840 and 1860. H. sericea is highly invasive, H. gibbosa and H. suaveolens are moderately invasive and H. salicifolia is not invasive. The allocation of reproductive energy, germinability, the ability to survive fires and to germinate in burnt and unburnt areas, and the nutrient content of seeds were assessed for the four species. The information was used to investigate whether the success of H. sericea relative to the other three species could be explained by the superior expression of any trait. The most important trait which separates H. sericea from the other species is its ability to produce a large seed bank in its adopted environment in the absence of seed predators. Seed production in H. sericea shrubs with an above-ground dry mass of 8 kg is four times greater than H. gibbosa and more than 16 times that of H. suaveolens. Although H. salicifolia also produces a large seed bank, its seeds are unable to survive fires due to inadequate insulation by the small follicles. The results are compared to dispersal and seed bank data for indigenous South African Proteaceae, which have low dispersal and suffer high pre-dispersal seed predation. We suggest that potential invasives in the fynbos can be identified as species that have: (i) a potentially high seed production that is limited by specialized predators; (ii) an ability to disperse over long distances; and (iii) are pre-adapted to frequent fires and low soil nutrients. The data also support the current strategy of combatting H. sericea using specialized insect seed predators.     

Pubescence,floral temperature and fecundity in species of Puya (Bromeliaceae) in the Ecuadorian Andes

Summary The effects of inflorescence pubescence on floral temperatures and fecundity were examined in four species of Puya in the Ecuadorian Andes. These species span an elevational range from 1,980–4,000 m and comparisons among these species showed that pubescence production increases significantly with elevation. Flower temperatures of glabrous or slightly pubescent species of Puya from lower elevations closely tracked air temperature, while those of the pubescent páramo species did not. Pubescence removal experiments on Puya hamata, a páramo species, demonstrated that pubescence is an effective insulator, maintaining elevated flower temperatures. In Puya clava-herculis (also a páramo species) elevated flower temperatures were associated with higher seed set. Thus, the greater production of inflorescence pubescence in páramo species of Puya may be an important factor contributing to reproductive success in these higher elevation species.