Two new endemic species of Ophiorrhiza L. (Rubiaceae: Ophiorrhizeae) from Davao Oriental,Philippines

Two new species of Ophiorrhiza collected from Mt Hamiguitan Range Wildlife Sanctuary in Davao Oriental, Philippines, are herein described and illustrated. Ophiorrhiza erythropilosa is the third Philippine species possessing involucral bracts and is further characterized by its predominantly villose stems that appear red due to strikingly red-violet trichomes, subpersistent bifid stipules, linear involucral bracts without prominent midrib, and 4 mm long urceolate corolla that is villose outside and lightly puberulous inside. Ophiorrhiza hamiguitanensis is characterized by its coriaceous, lanceolate leaves with attenuate apex and base, brochidodromous venation, subpersistent bilobed stipules with slightly recurved acute tips, presence of 1.5–2.5 mm long linear ensiform bracts, heterostylous flowers, clavate calyces and broadly obcordate capsules.     

南溪楼梯草,云南荨麻科一新种

该文描述了自云南东南部发现的荨麻科楼梯草属一新种,南溪楼梯草(Elatostema nanxiense)。此新种与田林楼梯草(E. tianlinense)相似,但其叶具三出脉,边缘具浅圆齿或小钝齿,雄总苞苞片较少,8枚,排成一层,背面有1～3条纵肋,只1枚在顶端具角状突起而与后者相区别。此外,此新种与盘托楼梯草系的广布种盘托楼梯草(E. dissectum)的区别在于其茎被糙伏毛,叶呈椭圆形,具三出脉,雄头状花序的花序梗较短,雄总苞苞片较少,呈宽卵形或横长方形,背面有1～3条纵肋,雄小苞片有缘毛。     

Comparing Variational Properties of Homologous Floral and Vegetative Characters in Dalechampia scandens: Testing the Berg Hypothesis

The Berg hypothesis posits that, in plants with specialized pollination systems, floral characters should evolve to become integrated with each other and decoupled from vegetative characters. We test this hypothesis by comparing serially homologous and morphologically similar characters in leaves and involucral bracts in the Neotropical vine Dalechampia scandens, which has a specialized pollination system based on resin-collecting bees. The involucral bracts serve a number of specialized floral functions, including signaling and protection, that may put them under stronger selection for precision than the less specialized leaves. The homology and morphological similarity of the leaves and bracts allow us to make a sharper test of Berg’s hypothesis than is possible in most other systems. We found support for the hypothesis in that the bracts had lower coefficients of variation than the leaves for comparable traits. Also in support of the hypothesis, we found essentially zero phenotypic correlations between bracts and leaves at the same time that we found moderate correlations between different leaves and between different bracts. In contradiction to the hypothesis, however, we did not find higher correlations among traits within bracts than within leaves, and we found no evidence of bracts being more developmentally stable than the leaves.     

克钦楼梯草, 缅甸荨麻科一新种

该文描述了自缅甸北部发现的荨麻科楼梯草属一新种,克钦楼梯草。此种在体态上与骤尖楼梯草甚为相似,与后者的区别在于本种的每一茎节具正常叶和一退化叶,托叶狭披针状条形和无脉,雌总苞苞片无角状突起,雌小苞片较大,呈楔状长圆形,雌花具一小花被片,以及雌蕊具一宽倒卵球形柱头。     

Shoot apex and spathella: two problematical structures of Podostemaceae–Podostemoideae

The presence of a shoot apex and shoot apical meristem (SAM), said to be absent in subfamily Podostemoideae (Podostemaceae), is confirmed for Marathrum utile and M. foeniculaceum. The vegetative shoot axis is terminated by a small group of meristematic cells which are surrounded by the tissue of the adnate bases of foliage leaves. The slightly bulged tip of the shoot apex is embraced by the youngest leaf, facing the apex with its adaxial side. The study also refers to the spathella, a cup-shaped structure covering obligatorily the young flower bud in Podostemoideae. The occurrence of two separate peaks in the young spathella of M. foeniculaceum supports the view that the spathella is formed by two fused bracts (hypsophylls). The two bracts are perpendicular to the distichous foliage leaves below the spathella. The scaly leaflet on the spathella of A. latifolia apparently does not represent a rudimentary blade of the spathella, but is interpreted as a separate bract. The occasional occurrence of scales below or above the spathella points to a reduction of bracts that were originally present in greater number on the pedicels.     

GLANDULAR STRUCTURES OF HOLOCARPHA AND THEIR ONTOGENY

Carlquist , Sherwin . (Rancho Santa Ana Botanic Garden, Claremont, California.) Glandular structures of Holocarpha and their ontogeny. Amer. Jour. Bot. 46(4): 300–308. Illus. 1959.—Two types of advanced glandular structures occur in the 4 species of the genus Holocarpha. Sessile disk-shaped glands occur at the tips of upper leaves and of involucral and receptacular bracts. Unlike all other glandular structures of Madinae which have been investigated, these originate from several protodermal initials rather than a single one. These glands, however, represent modifications of a glandular trichome. The other type of glandular structure, termed hollow-stalked trichome here, occurs on the outer surface of involucral and receptacular bracts. These trichomes originate from a single cell but differ from others in the formation of a hollow stalk, the wall of which is one cell in thickness. Mesophyll of the bract, often with an included vascular bundle, is present as an intrusion into the base of the hollow stalk. Corresponding to the advanced nature of the glandular structures, the leaves show specializations in the “inrolling” of margins. Upper leaves have a cylindrical organization of vascular tissue, whereas basal leaves are “normal” and leaves of the main stem are intermediate. The species of Holocarpha differ in certain details of leaf anatomy and structure of hollow-stalked trichomes. The systematic distribution of these is given. The essential unity of the various glandular structures of Madinae is discussed both in terms of mature structure and ontogeny, and the steps in the evolution of these are suggested.     

江津楼梯草, 重庆荨麻科一新种

描述了自重庆南部发现的荨麻科楼梯草一新种,江津楼梯草(Elatostema jiangjinense)。此新种与锐齿楼梯草(E. cyrtandrifolium)近缘,两者的区别在于江津楼梯草的叶在狭侧具2条二级脉,托叶卵形或披针形,以及雄总苞片在顶端具长角状突起。     

Shoot development ofAucuba japonica I. Morphological study

The shoot development ofAucuba japonica was studied morphologically. The shoot shows dichasial branching in connection with the formation of a terminal inflorescence and shows a decussate phyllotaxis even in the reproductive phase. The sequence of initiation of successive foliar appendages is very precise, hence the foliage leaf, scale leaf and bract can be compared with each other even at their stages of initiation. In the stage of proximal foliage leaf formation the shoot apex is flat, while in the stage of formation of distal foliage leaves, bud scales and proximal bracts, it becomes concave. In the stage of formation of distal bracts the apex becomes domed. Plastochron durations are relatively long in the vegetative phase in comparison with other plants, and the duration from initiation of the first pair of appendages to that of the second is about one and a half months. Both male and female inflorescences exhibit basically a thyrsoid type of monotelic synflorescence.     

Übersicht zur systematischen Gliederung der Gattung Carlina Mit 3 Tafeln und 5 Abbildungen

In the tribe Cynareae the genus Carlina is a well limited taxon. The sequence of leaves and involucral bracts, and the form of heads are important characters for identification. The genus is classified into the subgenera Carlowizia, Lyrolepis, and Carlina. The ancestral subgenera Carlowizia and Lyrolepis are endemits of the Canary islands respectively the south Aegean islands. The very variable species of the Mediterranean-Central European-West Asian subgenus Carlina are divided into sect. Corymbosae, sect. Mitina, sect. Carlina, and sect. Heteracantha. These sections are well distinguished by several morphological and anatomical features. A new species C. kurdica) is described from north-west Iraq.     

The movement of involucral bracts of Syngonanthus elegans (Eriocaulaceae-Poales): Anatomical and ecological aspects

Syngonanthus elegans flowers are distributed in capitula whose involucral bracts open and close in a diurnal rhythm. The anatomy of these bracts was studied to understand how such movements occur and how it influences reproductive ecology of the species. The involucral bracts have a single layered epidermis composed of thick-walled cells on the abaxial surface, which are responsible for the movement. Since they are hygroscopic, these cells swell when they absorb water from the surrounding environment, causing the bracts to bend and the capitula to close. In natural conditions, the capitula open by day, when temperature increases and the relative air humidity decreases, and close at night, when temperature decreases and the relative air humidity increases. The involucral bracts may thus protect the flowers from abiotic factors, exposing them only at the time of the day when temperature is higher and insects are more active, favoring pollination by small insects. The closed capitula do not only protect the flowers, but they also function as a shelter for floral visitors as Brachiacantha australe (Coccinellidae) and Eumolpini sp. (Chrysomelidae). These small Coleoptera pollinate the flowers of S. elegans during the day and remain within the closed capitula during the night, in a possible mutualistic relationship.     

Comparative floral biology of Rhynchospora ciliata (Vahl) Kukenth and R. pubera (Vahl) Boeckeler (Cyperaceae): the role of white involucral bracts in attracting pollinating insects

Although Cyperaceae are considered anemophilous, some species exhibit features that are attractive to pollinators, such as the white UV‐reflecting involucral bracts of Rhynchospora ciliata. But how effective are these conspicuous adaptations? To address this question, we tested the hypothesis that species such as R. ciliata are visited by greater numbers of pollinating insects than similar species with green involucral bracts, such as R. pubera. We compared the floral biology of both species and the number of visits to sympatric populations of each species, associating them with the availability of pollen and the pollination system. We verified that species with white involucral bracts are preferred, because there were more visits to R. ciliata in the first 2 h the flowers were open. The peak visitation in R. pubera was 2 h after the flowers opened, when the pollen of R. ciliata was exhausted. Although the involucral bracts of R. pubera are green, the spikelet scales and anthers are white and reflect ultraviolet light. Overall, flowers of R. pubera exhibit fewer white or reflective surfaces and are probably less conspicuous to a bee than those of R. ciliata. It is possible that R. pubera is a second option for visitors after the first 2 h of anthesis. The two different peaks in visitation minimize interspecific competition for pollinators, suggesting that R. ciliata and R. pubera together could attract more generalist pollinators and, instead of competing, facilitate the pollination of both species. Although R. pubera is autogamous and self‐compatible, both wind and insects are important to its reproductive success.     

Goodmania (Polygonaceae), a new genus from California

A new genus,Goodmania, is described for the species currently known asOxytheca luteola Parry of central and southern California. A member of Polygonaceae, subfamily Eriogonoideae,Goodmania is an isolated genus, distinct fromEriogonum by the awned bracts, and fromOxytheca by its involucral bracts not forming a distinct tube, yellow flowers, non-glandular pubescence, and small, paired cauline leaves.Goodmania is seemingly related to the Death Valley endemic,Gilmania, but differs in having a whorl of five involucral bracts subtending the cluster of short-pedicellate flowers.     

A NEW SPECIES AND NEW SECTIONS OF RHIPIDOCLADUM (POACEAE: BAMBUSOIDEAE)

Rhipidocladum longispiculatum, a woody bamboo from the montane forests of Colombia, is described and illustrated. A classification of Rhipidocladum into three sections is proposed based on differences in internode structure, culm leaves, fimbriae of the foliage leaf sheaths, inflorescences, spikelet bracts, and foliar anatomy and micromorphology. Rhipidocladum section Rhipidocladum is distinguished by the zigzag rachis of the inflorescence and obtuse spikelet bracts, and includes only one species, R. harmonicum. Section Didymogonyx is characterized by alternating long and short internodes, and includes R. longispiculatum and R. geminatum. Section Racemiflorum is distinguished by its relatively long culm leaf blades, racemiform inflorescences, and mucronate or aristate spikelet bracts; the remainder of the species of the genus are classified within this section. A review of morphology, foliar anatomy, and micromorphology of the Arthrostylidiinae, the subtribe to which Rhipidocladum belongs, is presented. The problem of generic classification within the subtribe is discussed with respect to its mosaic pattern of morphological and anatomical variation.     

Johanneshowellia (Polygonaceae: Eriogonoideae), a new genus from the Intermountain West

A new genus ofPolygonaceae subfam.Eriogonoideae is established for what has long been known asEriogonum puberulum. NamedJohanneshowellia in honor of the late John Thomas Howell (1903–1994), a new combination,J. puberula, and a new species,J. crateriorum, are established. The common name Howell's-buckwheat is proposed for the group. The new genus differs from other members of the subfamily in having its involucral structure reduced to a spiral of four to seven bracts each of which is associated with a flower-bearing pedicel and a basal bractlet. In bud and early anthesis the outer two (rarely outer three) bracts may be partially connate, but typically become separate at full anthesis. The connate, ternate, foliar bracts at the base of the node act as a traditionalEriogonum-like involucre surrounding the branches of the inflorescence, the involucral bracts, and the flowers. Members of the new genus are found in the arid Intermountain West of the United States from Inyo Co., California, across Nevada to western Utah.     

A new ribbon-leaved aquatic bulrush in madagascar (Cyperaceae: Scirpus)

Scirpus heterophyllus, known only from Madagascar, is described and compared withS. erectus. The unusual leaf dimorphism is pointed out, and the presence of chlorenchyma above and below air cavities in leaf blades and involucral bracts is regarded as a useful taxonomic character.     

不同色彩珙桐叶片和苞片解剖结构及色素含量比较研究

以生长于同一生境下的粉红珙桐(粉红色叶片、苞片)与普通珙桐(绿色叶片、白色苞片)为试材,对比两种色彩珙桐叶片/苞片解剖结构和色素含量的差异,以揭示珙桐色彩转变的规律。结果显示：(1)两种珙桐叶片均属于异面叶类型,栅栏组织由一层长柱形细胞整齐排列而成,海绵组织排列疏松,部分粉红叶片的上表皮细胞向外凸起,绿叶无此现象;粉红叶片的总厚度及其表皮角质层、栅栏组织和海绵组织厚度都高于绿叶,而表皮较薄。(2)两种珙桐苞片均无栅栏组织和海绵组织的分化,粉红苞片上表皮细胞明显隆起,上表皮角质层增厚,而下表皮变薄。(3)粉红叶片的类黄酮、花色苷含量分别是绿色叶片的1.52倍、3.67倍,两者的光合色素含量无显著差异,但粉红叶片的叶绿素a/b值比绿色叶低很多;粉红苞片花色苷含量显著高于白色苞片,而两者类黄酮含量差异不大。研究表明,花色苷是珙桐叶片和苞片色彩转红的直接因素,类黄酮有助于叶片呈红色;粉红珙桐叶片/苞片的解剖结构发生了一定变化,对光能的利用效率更高,对阴湿环境的适应性增强。     

Chamaesium jiulongense sp. nov. (Apiaceae) from Sichuan,China

Chamaesium jiulongense X. L. Guo & X. J. He, a new species of Apiaceae from Mt Haite in Jiulong County, Sichuan Province, China, is described. The new species differs from other Chamaesium species by its ultimate segments of the leaves which are 1–3‐lobed, rarely entire, with a narrow, minutely incised, pale brown margin, as well as by the presence of leaf‐like bracts, bracteoles longer than flowers, pubescent styles and oblong fruit with obsolete calyx. Morphological and micromorphological characters of the new species are provided and illustrated.     

Physiological characterization of photosynthesis,chloroplast ultrastructure,and nutrient content in bracts and rosette leaves from <Emphasis Type="Italic">Glaucium flavum</Emphasis>

Glaucium flavum is a biennial plant that bears a rosette of leaves, producing a flower stalk, bracteate monochasium, in its second year. The aims of this work were both to investigate the contribution of bracts to gas-exchange activities in this species and to compare this contribution to that of rosette leaves. In addition, we investigated the extent to which its responses can be explained by chloroplast ultrastructure, as well as the possible role of nutrient concentrations in the physiological responses of both leaf types. Gas exchange and plant characteristics regarding chlorophyll fluorescence were examined in a field experiment; we also determined leaf relative water content, tissue concentrations of photosynthetic pigments, chloroplast ultrastructure and nutrient contents. Although bracts indeed contributed to gas-exchange activities of G. flavum, rosette leaves showed higher values of net photosynthetic rate and stomatal conductance to CO₂ for photosynthetic photon flux density above 200 μmol m⁻² s⁻¹. The incongruities in photosynthetic rates between bracts and leaves may be explained by the bigger chloroplasts of rosette leaves, which results in a larger membrane surface area. This agrees with the higher pigment concentrations and quantum efficiency of photosystem II values recorded as well for rosette leaves. On the other hand, bracts showed higher sodium concentrations, which could be a mechanism for salt tolerance of G. flavum.