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1.
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。 相似文献
2.
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。 相似文献
3.
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。 相似文献
4.
报道了河南省五加科(Araliaceae)1个分布新记录属及其属下1新记录种,梁王茶属(Metapanax J. Wen & Frodin),异叶梁王茶[Metapanax davidii (Franchet) J. Wen & Frodin]。该种为常绿灌木,叶为单叶或掌状分裂,花聚生为伞形花序,再组成顶生的圆锥花序,苞片早落,花梗具关节,子房2室,核果,扁球形,花期7~8月,果期9~11月。讨论了该种叶、花、果的形态学变异特征和其区系地理学意义。该新记录的发现对梁王茶属的系统分类、迁移演化以及药用植物资源开发具有重要的意义。 相似文献
5.
该文描述了荨麻科三新种:(1)自中国重庆市发现的荨麻科荨麻属一新种,城口荨麻。此种与异株荨麻有亲缘关系,区别特征为此种的茎被少数刺毛,叶片多为心形,雄、雌花序均不分枝,瘦果在中央稍凹陷。(2)自中国广西发现的荨麻科赤车属一新种,来宾赤车。此种与特产云南东南部的富宁赤车相近缘,与后者的区别在于本种茎的毛开展或向上弯曲,叶片长椭圆形,基部斜楔形,雌花具3~4枚花被片,其中1~2枚较大花被片在背面顶端具一长筒状突起。(3)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。 相似文献
6.
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. 相似文献
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8.
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. 相似文献
9.
楼梯草属苞片形态和演化趋势 总被引:2,自引:0,他引:2
(Ⅰ)对荨麻科楼梯草属的苞片和小苞片的形态进行了全面研究。(Ⅱ)该属原始群疏伞楼梯草组的雄聚伞花序苞片在每花序为15-90枚,纸质,绿色,狭卵形、狭三角形或条形,长0.5-4mm,扁平,无任何突起,而与楼梯草族的冷水花属和赤车属的聚伞花序苞片极为相似,因此,上述各种形态可以视为楼梯草属苞片的原始特征,并据此观察到总苞苞片的以下演化趋势:(1)近等大,形状相似,在花序托边缘轮生形成一层→排列为二层,外层2苞片对生,较大,内层苞片较小,形状稍不同;(2)狭卵形,狭三角形或条形→宽卵形或宽三角形,或扁半圆形→由于长度强烈缩小,宽度增大而最终消失;(3)扁平→顶端兜形→船形→船形,顶端突起成细筒;(4)无任何突起0背面有1龙骨状突起,或有1-6条纵肋或狭翅1顶端具短到长的角状突起→背面顶端之下具角状突起;(5)分生→基部合生→由于长度强烈缩小,宽度强烈增大,总苞苞片合生成一横条形狭片;(6)在数目上,由每花序的7-45枚,一方面增加到50-180枚,另一方面则减少到5枚以下。同时,观察到小苞片形态以下演化趋势:(1)膜质,半透明,白色0具褐色线纹或呈褐色→呈黑色1薄膜质,透明,无色;(2)扁平→顶端兜形→船形;(3)无任何突起→顶端或在背面顶端之下具角状突起;(4)在数目上,由每花序的7-45枚一方面增加到100或数百枚,甚至达1千到数千枚,另一方面则减少到5枚以下,甚至到0枚。上述演化趋势有助于了解属下各级分类群的演化水平。 相似文献
10.
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. 相似文献
11.
Marccus Vinicius Alves Wm. Wayt Thomas Maria Das Graças Lapa Wanderley 《Brittonia》2002,54(2):124-135
Five new species ofHypolytrum Rich. from South America are described and illustrated.Hypolytrum amorimii andH. jardimii, both of sect.Bullata T. Koyama, are species with pseudopetioles and colored leaves, and endemic to the rain forest of southeastern Brazil.Hypolytrum bahiense (sect.Hypolytrum), a species with a lax synflorescence and two, free and lightly scabridulous floral bracts, is endemic to the rain forest
of southeastern Bahia, Brazil.Hypolytrum leptocalamum (sect.Hypolytrum), a species with lax synflorescence and spike ellipsoid to cylindrical, is restricted to area of tepuis in the Guayana Highland
(Brazil, Guyana, and Venezuela).Hypolytrum paraense (sect.Hypolytrum), a species with three, partly connate and densely scabridulous floral bracts, is restricted to the rain forest of the Amazon
Basin, in the state of Pará, Brazil. 相似文献
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13.
Thomas G. Lammers 《Brittonia》1998,50(2):233-262
Burmeistera, Centropogon, and Siphocampylus together comprise more than 500 species endemic to the Neotropics, Current knowledge of these genera is unsatisfactory, with
much diversity yet to be described. Over the past seven years, one out of every 28 specimens received for identification has
represented a new species, many characterized by unique or unusual character states. Siphocampylus smilax (Bolivia) is unique in the genus in its parallelodromous leaf venation and extra-floral nectaries. Centropogon dianae (Peru) cannot be accommodated in any recognized infrageneric taxon, and a new section, Centropogon sect. Niveopsis, is proposed for it. The flowers of C. steinii (Ecuador) are the smallest known in the genus, while C. connatilobatus (Venezuela) is the first species to combine arbusculiform pubescence and connate calyx lobes. Burmeistera venezuelensis is only the second species of the genus known to occur in Venezuela and the first to be endemic; similarly, Centropogon wilburii is only the third species of Centropogon known from Mexico and the first to be endemic to that country. Additional novelties are also described. 相似文献
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15.
邓绎诚 《热带亚热带植物学报》2022,30(3):395-396
报道了中国兰科植物一新记录种:双眼带叶兰(Taeniophyllum biocellatum J. J. Sm.),并提供特征描述和彩色图片。该种与近缘种的区别特征为花序柄和花序柄苞片浅绿色,根呈圆柱形,花序短;紫红色药帽的中间具2个黄色小点,唇瓣开口大,萼片和花瓣黄绿色。 相似文献
16.
Cenomanian-Turonian sediments from the Sarbay locality in north-western Kazakhstan have yielded a rich assemblage of plant fossils including well preserved flowers, fruits, and seeds of angiosperms. This work describes fossil seeds assigned to theMagnoliaceae and theIlliciaceae. Three new species of the extinct magnoliaceous genusLiriodendroidea, L. asiatica, L. costata, andL. tenuitesta, are established and new information on the previously described species,L. alata, is provided. TheLiriodendroidea seeds are closely similar to seeds of extantLiriodendron, but are distinguished in being much smaller and winged. A new genus and species,Illiciospermum pusillum, is established based on seeds with close similarity to those of the extant genusIllicium. The seeds are small, anatropous and exotestal with outer epidermis of testa forming a palisade layer. The facets of the palisade cells have deeply undulate anticlinal walls. The micropyle area is seen on the outer integument as a transverse slit placed on a raised strophiole-like structure close to the hilum. TheIlliciospermum seeds represent the first unequivocal record of theIlliciaceae in the Cretaceous. Another seed of possible illiciaceous affinity is described as aff.Illiciospermum sp. 相似文献
17.
描写了自黑龙江省发现的紫堇科紫堇属一新种,鹤岗延胡索。此种与新疆元胡相似,但本种叶的小叶多在顶端具1~5牙齿,花序苞片有3~5小裂片,上花瓣及其辦片和距均较小,蜜腺呈狭卵球形,弯曲,顶端尖锐而与新疆元胡相区别。 相似文献
18.
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. 相似文献
19.
Comparative floral biology of Rhynchospora ciliata (Vahl) Kukenth and R. pubera (Vahl) Boeckeler (Cyperaceae): the role of white involucral bracts in attracting pollinating insects
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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. 相似文献
20.
A new specimen of an araucarian cone,Araucaria nihongii, was found attached to the vegetative organs ofYezonia vulgaris, and is described asAraucaria vulgaris comb. nov. Thick branches show characteristic bark structure with lenticular patches. Secondary wood is usually araucarioid.
Leaves are arranged helically on shoots, which are imbricate, appressed and fused to surface of the stem. External and anatomical
features of leaves closely resembleBrachyphyllum. The seed cone is spherical with winged bracts and thin ovuliferous scales. One seed is borne per cone-scale complex. The
seed coat and nucellus wall show typical araucarian structure. An araucarian plant that boreBrachyphyllum-like foliage and aEutacta-like seed cone was predicted by Harris in 1979. This reconstructed plant,Araucaria vulgaris, supports this theory and proves the presence of an extinct characteristic-form of the genus. A new section of the genus
was proposed forAraucaria vulgaris.
Structure and Affinities of the Petrified Plants from the Cretaceous of Northern Japan and Saghalien XV, Consecutive number
from previous paper (Nishidaet al. 1993). 相似文献