Addendum of pollen morphology of genus Peucedanum L. in Southwest China
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In this paper,pollen morphology of 6 species of the genus Peucedanum was investigated.Pollen grains of all the species were examined by LM and SEM.Among them 3 species were palynologically reported here for the first time.The study showed that pollen grains of Peucedanum were in various shapes.Their frame work was trigonal in solid form Ktricolporate,pleurot reme and exine 2-lauered.The statification of exine was clear.According to the characteristics of the pollen grains in Peucedanum,it may be divided into clearly distinguished types: Rectangular type and Equatorially-constricted type.The evolutionary trends of pollen types were as follows: retangular type-equatorial-constrictd type.Pollen information supports Peucedanum as an advanced taxon in Umbelliferae.The trendency of evolution in Peucedanum is that:the size of pollen is from big to small;equater is from straight to contractus.According to pollen information,sect.Bracteolata shoud be a comparatively primitive taxon.Keywords:
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Reticulate
Gesneriaceae
Morphology
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The genus Centaurea L. is one of the largest genera in the family Asteraceae. The number of taxa included in this genus ranges from 500 to 600 worldwide. Iran is one of the major centers of diversity for this genus. Pollen morphology has proved useful in the systematics of Asteraceae, as well as in that of some of its genera and species. The pollen morphology of 19 taxa of the genus Centaurea was investigated in detail by light and scanning electron microscopy. Examination under light microscopy showed pollen grains to be tricolporate, isopolar, radially symmetrical, oblate spheroidal, prolate spheroidal, subprolate, tectum perforate and scabrate. Based on the exine ornamentation observed under scanning electron microscopy, we identified two types of pollen grains, designated type I (dense acute spinules) and type II (sparse spinules). All of the taxa evaluated resemble Wagenitz's Jacea type. We present micrographs of pollen grains, together with descriptions of the characteristics of their structure. We found that the pollen characters (shape, exine structure, sculpturing) were useful for classification.
Centaurea
Morphology
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The pollen morphology of 40 Convolvulus L. taxa was examined using scanning electron microscopy. Of these, fourteen, including eight endemic to Iran, were studied in detail for the first time. Pollen was evaluated mainly for the following diagnostic characteristics: polar axis, equatorial axis, P/E ratio, pollen shape, colpi length, colpi width, type of tectum architecture, perforation diameter and number of perforations per unit area. Pollen is radially symmetrical, isopolar and tricolpate. The largest pollen belongs to C. armenus Boiss. & Kotschy ex Boiss. and C. persicus L, while C. leptocladus Boiss. has the smallest pollen. Pollen shape is polymorphic. However most species have subprolate and prolate-spheroidal pollen. The tectum is perforate (the most common), microreticulate or reticulate. Supratectal elements are present as granules more or less irregularly scattered over the whole surface. In the present study, pollen morphological characters were compared with previous results. C. persicus and C. leiocalycinus Boiss. have distinct pollen compared with other species from Iran. Although pollen characters alone are insufficient to reconstruct the taxonomic relationships within Convolvulus, palynological data can provide some useful information for species-level revisions.
Convolvulus
Reticulate
Morphology
Eudicots
Convolvulaceae
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Abstract The pollen morphology of 12 taxa belonging to four genera of Boraginaceae have been investigated by LM and SEM. The pollen grains vary from genus to genus, and even in some species. In general, the pollen grains are small, isopolar, sometimes subisopolar, colporate with four, five or more apertures; apertural membrane granular. Exine tectate, tectum psilate. The taxonomic implications of the pollen morphological features are discussed.
Boraginaceae
Morphology
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Pollen of 72 species from 7 genera of the Asphodelaceae was studied by means of LM and SEM in order to investigate their taxonomic relationships. The pollen of all the genera investigated is heteropolar, monosulcate, non-operculate and differs in size, form and exine ornamentation. The species of Eremurus are homogenous palynologically and studies of this genus do not support the segregation of the genera Henningia, Selonia, and Ammolirion. The pollen of Bulbinopsis mainly differs from the pollen of Bulbine species in having a perforate-areolate exine surface (B. bulbosa) but the genera are close in their other palynological features. The genera Asphodelus and Asphodeline have the largest, almost spheroidal grains with the thickest exine but differ in details of exine ornamentation. The species of Kniphofia are very close palynologically.
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We analyzed the pollen grains of 11 species within the subfamily Bombacoideae. The pollen grains were acetolyzed, after which they were analyzed and photographed under light microscopy. Unacetolyzed pollen grains were analyzed and photomicrographed under scanning electron microscopy. We studied pollen characters such as shape, size, exine ornamentation and aperture type. The species were separated by a pollen key, which considers the presence or absence of "calotte" in the pollen grains. This attribute separated Ceiba and Eriotheca from the other genera. Some species are differentiated by specific characters: in Bombacopsis glabra and B. stenopetala, the sexine is rugulate or "vermiculate" with isolated pilate elements; in B. calophylla, the pollen grains are sinu-aperturate; Ceiba speciosa show atypical, duplicolumellate sexine; C. erianthos is the only species with 5-colporate pollen grains and a pentagonal amb; in Pachira aquatica the reticulum has muri with spiculaspinulose muri ("reticulum cristate"). The variation in the pollen morphology confirms the eurypalynous status of the genera studied here.
Sensu
Aperture (computer memory)
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Morphology
Aperture (computer memory)
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Magnoliaceae
Subfamily
Morphology
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Pollen morphology of 6 species, 1 variety and 1 form of 4 genera (Cham aedaphne Moench., Ledum Linn., Phyllodoce Salisb., Vaccinium Linn. ) of family Er icaceae, distributing in northeast of China ,was examined in the light microsc op e(LM) and with the scanning electron microscope(SEM). All of the pollen grains o f the 4 genera are characterized in tetrahedral tetrad. Pollen grains of the 4 g enera are spheroidal or subspheroidal with 3-colporates, which shaped as half-c olpi due to two neighborly grains of tetrahedral tetrad link together. Exine is composed with two layers in LM. The ornamentation of the exine is reticulate or granulate. The mean size of the pollen grains ranges from 34.0 to 43.7μm. Pol len grains are diverse in size and in ornamentation of the exine. These can be taken as the characters for identification of species.
Reticulate
Tetrad
Morphology
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The genus Heracleum (Umbelliferae) consists of over 70 species. So far, 26 species and 3 varieties of them are found in China; about 25 species and 1 variety distributed in Sorth -westen China. Hengduan Mountains is one of the another centers of distribution in the world. In the present paper, pollen morphology of 16 species of the genus Heracleum from this area was investigated. Pollen grains of all the species were examined by LM, SEM. Among them 14 species were palynologically reported here for the first time. The study showed that pollen grains of Heracleum in vary shape. Their framework was trigonal in solid form, tricolporate, pleurotreme and exine 2-lauered. The stratification of exine was clear and columellae usually were distinct. According to the characteristics of the pollen grains in Heracleum, it may be divided into clearly distinguished types: Rectangular type andEquatorially-constricted type. The evolutionary trends of pollen types were as follows: rectangular type→equtorial-constricted type. Pollen information supports that O. Drude (1898) etc. treated Heracleum as an advanced and nutural taxon in Umbelliferae. According to pollen information, Sect. Wendtia should be a comparatively primitive taxon, and Sect. Millefolia shorld be an advanced taxon in this genus.
Morphology
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