Anatomy of the Secondary Phloem and the Crystalliferous Phloem Fibers in the Stem of Torreya grandis

The structure of the secondary phloem and the development of the crystaleiferous phloem fibers in the stem of Torrey grandis were observed under the ligth microscope and SEM. The secondary phloem is composed of sieve cells, phloem parenchyma cells, crystalliferous phloem fibers and stone cells in the longitudinal system, and the uniserite homogeneous phloem rays consisting of parenchyma cells only in the radial system. In the cross section, there are 3–9 sieve cells in radial rows forming discontinuous tangential layers, the crystalliferous phloem fibers often in a single discontinuous tangential layer and the stone cells dispersed in rangential layer of phloem parenchyma. The developmental process of crystalliferous phloem fibers is as follows: initial cells appeared in the end of April and were well differentiated in the first week of May. Some crystals were deposited in the primary wall, while others were free in the cell. At the end of May, the secondary wall of most crysalliferous phloem fibers started to be thickened. With the thickening of the secondary wall, all the crystals were embedded in the wall from June to August From the end of September to the early days of October, the crystalliferous phloem fibers reached their full maturation. It is shown by microchemical identification and EDAX analysis that the crystals embedded in the wail of crystalliferous phloem fibers are calcium oxalate crystals.     

A Study on the Genus Cephalotaxus Sieb. et Zucc.

The genus Cephalotaxus contains a small number of species. It is adequately appreciated as a newly discovered cancerresistant medicament for the alkaloids obtained from its branches leaves and barks are of curative effect. This paper deals with the classificatory revision based on the morphological features, with the reference to the anatomical characters of leaves, types of alkaloids and pollen morphology observed. Two new combinations are proposed, and 4 species and varieties are reduced in the paper. The genus Cephalotaxus is thus suggested to consist of 2 sections and 9 species. The trees occur in East Asia and the north of Indo-China, with 88% found in China where is the distribution centre and refuge of the genus. The genus in discussion is of unique morphological features which are distinctly different from these of Amentotaxus, Cephalotaxaceae, containing a single genus of Cephalotaxus, is closely related to Taxaceae, and therefore the Cephalotaxaceae is best placed in the Taxinieae of Coniferales.     

A study of the alkaloids in Cephalotaxus and their bearing on the chemotaxonomic problems of the genus

The family Cephalotaxaceae contains so far known only 1 genus with 8 species and possibly 2-3 varieties mostly native in China. In recent years, some ester alkaloids of Cephalotaxus have been shown significant activity in a variety of experimental leukemia systems. 6 species (including varieties) of the genus have been investigated for their alkaloids. The detected alkaloids in Cephalotaxaceous plants, from the chemotaxonomic point of view, may be of some significance to the plant systemstics. Our present study has indicated that: (1) The species C. sinensis and C. fortunei (C. oliveri ?) are chemically considered to be more primitive than others, while C. harringtonia, C. hainanensis and C. wilsoniana (including C. mannii?) seem to be derived. (2) Chemical evidence has suggested that the genus Cephalotaxus be accorded a family rank. (3) On the basis of morphology, anatomy, embryogeny, geographical distribution etc., the recent findings in the chemistry of Cephalotaxaceae support the inclusion of Cephalotaxaceae, Taxaceae and Podocarpaceae in Taxineae of Coniferales. (4) C. fortunei, C. hainanensis and C. oliveri (C. harringtonia) contain richer ester alkaloids than other species of the genus. C. fortunei which has a wide distribution and great amount in many provinces of China, may prove to be a good new resource for antitumor medicine.     

红豆杉科次生韧皮部的比较解剖

在光学显微镜及扫描电镜下,比较观察了红豆杉科Ｔａｘａｃｅａｅ５属即红豆杉属Ｔａｘｕｓ,白豆杉属Ｐｓｅｕｄｏｔａｘｕｓ、穗花杉属Ａｍｅｎｔｏｔａｘｕｓ,榧树属Ｔｏｒｒｅｙａ和澳洲红豆杉属８种植物茎次生韧皮部的结构。其主要结果为：红豆杉科植物茎次生皮部由轴向系统和径向系统两部分构成。轴向系统由筛胞,韧皮薄壁组织细胞,蛋白细胞及韧皮纤维组成;径向系统由韧皮射线构成,但是,在横切面上,各个组成分子的层次有     

Systematic implications of wood and bark anatomy in the Pacific Island genus Meryta (Araliaceae)

Wood anatomy was examined in 16 species of Meryta (a genus of c . 35 species) and bark anatomy was studied in 12 species. All but two of these taxa form an assemblage corresponding to the Northern Arc clade, one of two major groups identified by a recent molecular phylogenetic study. M. sinclairii and M. tenuifolia (corresponding to the New Zealand/Fiji clade) differ distinctly by having more numerous simple perforation plates, multiseriate rays with few marginal rows, and the absence of sclerified cells in collapsed secondary phloem, a bark feature that has not yet been found elsewhere in Araliaceae. The increase in abundance of simple perforation plates in the wood of these two species is not accompanied by a decrease in the number of bars on scalariform perforation plates. The wood structure of Meryta bears a strong resemblance to members of the Pacific Schefflera clade, sharing similar ranges of variation of several features. Bark characters, such as the diameter of the cortical secretory canals, the types of crystal in cortical cells, the types of axial parenchyma cell in collapsed secondary phloem, and the presence of sheath cells by phloem rays, appear to be of diagnostic value for some species of Meryta .  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 153 , 363–379.     

Anatomy of Secondary Phloem of Glyptostrobus in Relation to Its Systematic Position

A anatomical characters of secondary phloem in Glyptostrobus pensilis (Staunt.)Koch were observed by means of both light and scanning electron microscopy(SEM). The secondary phloem is composed of axial and radial systems. In the axial systems, the phloem consists of sieve cells, phloem parenchyma cells, albuminous cell and phloem fibers. In the radial systems, it consists of phloem rays. The alternate arrangement of different cells in cross section results in tangential bands. The sequence of radial arrangement follows the pattern of sieve cells, phloem parenchyma cells, sieve cells and phloem fibers, sieve cells. Many crystals of calbium oxalate are embedded in the radial walls of seive cells. The phloem fibers are of only one type. The phloem rays are homogeneous, uniseriate. According to the anatomical characters of secondary phloem of Glyptostrobus pensilis (Staunt.)Koch and comparison with the other genera of Taxodiaceae, Glyptostrobus, Metasequoia and Taxodium have close relationships.     

Spatial relation between xylem and phloem in the stem of Hibiscus cannabinus L. (Malvaceae)

The distribution of the phloem in relation to the xylem was examined in the stem of Hibiscus cannabinus L. with reference to a report in the literature that this species has internal (intraxylary) phloem, a feature not previously observed in the Malvaceae. In the present study, the stem was found to have phloem only outside the xylem (external or extraxylary phloem). In the protophloem, the sieve tubes are obliterated while the internode elongates and the associated cells become fibres with thick secondary walls. Fibres occur in the secondary phloem also. As seen in transections of stems, the secondary xylem forms a continuous ring. The primary xylem extends in the form of arcs into the pith. The tracheary cells of the protoxylem become crushed or completely obliterated in elongating internodes. The associated parenchyma cells either retain thin walls or develop secondary thickenings.     

Development and morphology of stone cells in phloem of Toxicodendron vernicifluum

Key message

The morphology and development of sumac phloem sclereid were observed, sclereid was developed from phloem parenchyma and lignin was deposited in the cell wall of parenchyma and formation sclereid.

Abstract

Sumac [Toxicodendron vernicifluum (Stokes) F.A.Barkley] is a unique economic tree species in China. Raw lacquer is the sap flowing from the phloem of sumac. Stone cell clusters exist in the secondary phloem of sumac stem. In the present study, the morphology and development of stone cell clusters in sumac phloem were observed with optical microscope and transmission electron microscope. The distribution of lignin in the composition molecules of secondary phloem was observed with histochemistry method and fluorescence microscope. The results showed that phloem stone cells of sumac were developed from phloem parenchyma cells, and that lignin was deposited in layers in the cell wall of phloem parenchyma cells which cause the formation of stone cell clusters and which have the secondary wall. Studies on the ultrastructure of stone cells indicated that there was an obvious stratification and pits during the process of lignin deposition.     

水松的次生韧皮部解剖及其系统位置的讨论

在光学显微镜和扫描电子显微镜下观察,水松茎次生韧皮部的主要特征为：韧皮部由轴向系统和径向系统组成。轴向系统由筛胞、韧皮薄壁组织细胞、蛋白细胞和韧皮纤维组成,径向系统由韧皮射线组成。在横切面上,轴向系统的各组成分子以单层切向带交替有规律的排列,其排列顺序为：筛胞－韧皮薄壁组织细胞－韧皮纤维-筛胞。筛胞的径向壁上嵌埋有草酸钙结晶,韧皮纤维仅一种类型,韧皮射线同型、单列。根据水松茎次生韧皮部的解剖研究,并与杉科其它各属的有关资料进行比较,我们认为：水松属与水杉属和落羽杉属有较近的亲缘关系。     

杨柳科(Salicaceae)7种植物次生韧皮部的比较研究

本文研究和比较了杨柳科2属7种植物次生韧皮部解剖结构。结果表明:(1)杨属和柳属植物在次生初皮部解剖上有某些共同特征:次生韧皮部具有明显分层现象;韧皮纤维和含晶细胞与筛管分子、伴胞和韧皮薄壁组织细胞是切向带相间排列;筛管分子均为复筛板,端壁倾斜平均含有7-8个筛域。(2)两属植物在射线和晶体类型上有明显区别:柳属植物次生韧皮部无石细胞;杨属植物不具功能韧皮部中含有石细胞。(3)两属植物均有一些较为原始的韧皮部解剖特征。     

Investigation on Fertilization of Cephalotaxus

The structure of spermatogenous cell of Cephalotaxus is unique among the gymnosperms. While towards the mature stage, its nucleus is close to one side of the spermatogenous cell, and on the other side there is abundant and prominent . cytoplasm, which contain a group of the aggregate cytoplasms of radial arrangement similar to blepharoplast of spermatogenous cell of Ginkgo. But, there are two opposite blepharoplasts at either side of the nucleus in Ginkgo, and while there is only one blephareplast at one side in Cephalotaxus. This is one feature of the sexual process in Cephalotaxus. When the pollen tubes approach the top of the archegonia, the division of the spermatogenous cell takes place and there are two almost similar sperm cells both in size and morphology. It is interesting to note that the cytoplasm of the sperm cell contains certain granules of nucleolus-like structure, which appears to be a rare phenomenon among the gymnosperms. This is another feature of the sexual process in Cephalotaxus. These two features are the important characters of Cephalotaxaceae. The egg morphology of Cephalotaxus is also unique among the conifers, its outline looks like a carrot. The upper part of the egg is rather wide and is about 85 to 108 μm in width. On the other hand, the opposite end is gradually becoming narrow and about 910 to 1100 μm in total length. So the ratio of the length and width in the egg of Cephalotaxus is about 10:1. The structure of the egg in Celhalotaxus fortunei and C. oliveri have the following common feature: 1. When their eggs mature the cytoplasm of the egg at lower part of the nucleus possesses deep- staining and fine granules of 2 to 3 groups of aggregate cytoplasm. 2. During maturation of the egg, some of the granules of nucleolus-like structure are scattered in the cytoplasm. As fer- tilization takes place the number of these granules reaches the peak. This condition has been encountered in the egg of Amentotaxus argotaenia. Therefore we could conclude that they are closely related between Cephloraxaceae and Taxaceae. The fertilization of Cephalotaxus fortunei occured on May 10 to 24 (1983), and that of C. oliveri took place on May 28 to June 13 (1983). The fertilization of the genus belong to the type of undergoing mitosis prior to complete fuse of both male and female nuclei. This type of fertilization has been found only in Pinaceae and Cephalotaxaceae. After fertilization the structure of fertilized egg becomes prominent in polar organization. In other words, the cytop- lasm at upper part of the fertilized egg becomes highly vacuolated and that at lower portion, conversely, is rich in abundant proteinous vacuoles and certain granules of nucleolus-like structure dispersed in the cytoplasm. Because the division and differentiation of the proembryo are proceeding at the base of the archegonium, the large inclusions and the nucleolus-like granules may be involved in the nourishing and development of the proembryo.     

Studies on Pollen Morphology and Exine Ultrastructure in Cephalotaxaceae

The pollen morphology of Cephalotaxaceae was examined with LM, SEM and TEM. Pollen grains in this family are spheroidal or subspheroidal, rounded in polar view, but usually wrinkled with irregular shape. Pollen size is 22.6- 34.8 μm in diameter. There is a distinct or indistinct tenuity on distal face. The tenuity occasionally slightly rises above the outline of pollen grains, but often sukened. Exine rather thin, 1—1.5μm thick, layers obscure, surface of pollen grains is nearly psilate or weakly granulate. Under SEM exine is covered with fine and dense granules, and sparse Ubisch bodies are found on the granular layer. The Ubisch bodies are provided with minute gemmate processes on the surface. Acorrding to our observation under TEM, exine consists of ectexine and lamellate endexine, with the former divided into outer ectexine of granules densely arranged and inner ectexine of loosely arranged microgranules. Granules of the outer ectexine are relatively thick, and connected with each other, forming a structure just like tectum or separate from each other. Microgranules of the inner ectexine are distinct or indistinct. Endexine is provided with 5- 7 lamellae. As far as information of pollen morphology is concerned, Cephalotaxus oliveri is rather special in the Cephalotaxaceae. First, the tenuity in pollen grains occupies one half of the distal part, much larger than that of the other species in the family. Second, the ectexine in Cephalotaxus oliveri may be divided into two distinct layers, outer ectexine and inner ectexine. The former is made of a layer of sporopollenin masses, which are connected with each other to form tectumlike structure, while the latter consists of a layer of loosely arranged granules or small segments of sporopollenin. The inner ectexine is different from that of other species by having a thicker layer of sporopollenin granules. Based on these two features, we support the division of Cephalotaxus into two Sections, Sect. Pectinatae and Sect. Cephalotaxus. Pollen grains of Cephalotaxaceae are similar to those of the Taxaceae in having spheroidal shape and the tenuity on its distal face. These characteristics strengthen the evidence for a close relationship between the Cephalotaxaceae and Taxaceae. Although pollen grains of the Cephalotaxaceae and Taxaceae are similar in some characteristics, they have obvious differences in , for example, size of tenuity, the fine structure of Ulbisch bodies and of the outer and inner ectexine. On the basis of pollen morphology, the present author considers theCephalotaxaceae slightly more primitive than the Taxaceae.     

部分裸子植物叶片总蛋白分析

采用ＳＤＳ－ ＰＡＧＥ 技术, 分析了红豆杉科（Ｔａｘａｃｅａｅ） 植物南方红豆杉（ Ｔａｘｕｓ ｃｈｉｎｅｎｓｉｓｖａｒ－ ｍａｉｒｅｉ （Ｌｅｍｅｅ ｅｔ Ｌｅｖｌ－） Ｃｈｅｎｇ ｅｔ Ｌ－Ｋ－Ｆｕ） 、穗花杉（ Ａｍｅｎｔｏｔａｘｕｓ ａｒｇｏｔａｅｎｉａ （Ｈａｎｃｅ） Ｐｉｌ ｇｅｒ） 、云南穗花杉（ Ａ－ ｙｕｎｎａｎｅｎｓｉｓ Ｌｉ） 、白豆杉（ Ｐｓｅｕｄｏｔａｘｕｓｃｈｉｅｎｉｉ（Ｃｈｅｎｇ） Ｃｈｅｎｇ） 以及三尖杉科（Ｃｅｐｈａｌｏｔａｘａｃｅａｅ） 、植物三尖杉（ Ｃｅｐｈａｌｏｔａｘｕｓ ｆｏｒｔｕｎｅｉ Ｈｏｏｋ－ｆ－） 、粗榧（ Ｃ－ｓｉｎｅｎｓｉｓ （Ｒｅｈｄ－ｅｔＷｉｌｓ－） Ｌｉ） 、海南粗榧（ Ｃ－ｈａｉｎａｎｅｎｓｉｓ Ｌｉ） 、篦子三尖杉（ Ｃ－ｏｌｉｖｅｒｉ Ｍａｓｔ－） 和罗汉松科（Ｐｏｄｏｃａｒｐａｃｅａｅ） 、植 物罗汉松 （ Ｐｏｄｏｃａｒｐｕｓ ｍａｃｒｏｐｈｙｌｌｕｓ （ Ｔｈｕｎｂ－ ） Ｄ－Ｄｏｎ） 、鸡毛 松（ Ｐ－ｉｍｂｒｉｃａｔｕｓ Ｂｌ－） 、竹柏（ Ｐ－ ｎａｇｉ（Ｔｈｕｎｂ－） Ｚｏｌｌ） 、陆均松（ Ｄａｃｒｙｄｉｕｍ ｐｉｅｒｒｅｉ Ｈｉｃｋｅｌ） 共１２ 种植物的叶片蛋白, 在蛋白质水平上采用     

Anatomical Studies on Secondary Phloem of Euonymus bungeanus

The anatomical structures, especially the type, distribution and arrangement of the constituent elements in the secondary phloem of Euonymus bungeanus Maxim. have been studied. The results showed that the secondary phloem was thicker, consisted of sieve-tube elements, companion ceils ,phloem parenchyma cells ,secretory ceils and rays. Sieve-tube elements, phloem parenchyma cells and secretory cells were alternately arranged in tangential bands, forming a conspicuous zone-like constitution. There was no obvious boundary between the functional phloem and the non-functional phloem. Sieve-tube elements were long, slender cells with very oblique end walls and compound sieve plates. Sieve areas on lateral wall were highly differentiated. Companion cells were triangular in transection and slender in radial section. Mostly,two or three companion cells stayed along with one sieve-tube element. In the functional phloem, phloem parenchyma cells were also slender, containing a few starch grains;but in the nonfunctional phloem they enlarged and contained abundant starch grains. Secretory cells were longer than sieve-tube elements, consisting of rubber-like material. Rays were uniseriate. Finally, the authors also discussed the phylogenetic position of E. bungeanus, which may provide some references for further study of the classification of different genera of Celastraceae.     

Secondary phloem anatomy of Cycadeoidea (Bennettitales)

Secondary phloem anatomy of several species of Cycadeoidea is described from trunks in the Wieland Collection, Peabody Museum of Natural History. The trunks were collected from the Lakota Formation, Lower Cretaceous, Black Hills of South Dakota. Secondary phloem is extensively developed and consists of alternating, tangential bands of fibers and sieve elements, with rare phloem parenchyma. Uniseriate rays, 2-22 cells high, occur between every one to three files of the axial system. Fibers are long, more than 1200 μm, approximately 26.6-34.2 μm in diameter, and have slit-like apertures on the lateral walls. Sieve elements range from 16-25 μm in diameter and are up to 500 μm long. Elliptical sieve areas appear on both end and radial walls and measure 10 μm across; minute spots, which may represent sieve pores, are present within the sieve areas. Secondary phloem of North American Cycadeoidea is similar in organization (alternating tangential bands) and cell types (sieve cells, fibers, axial parenchyma) to that known in other extant and fossil cycadophytes and some seed ferns. The unusual pattern of cell types and thickness of secondary phloem is discussed in the context of plant habit, phloem efficiency, and potential phylogenetic importance.     

Comparative Anatomy of the Leaves of Cephalotaxus (Cephalotaxaceae)

The internal structure and cuticular characters of the leaves of Cephalotaxus were investigated under light microscope and scanning electron microscope. The materials used belong to 9 species, 2 varieties and 1 cultivar. The leaf characters of C. oliveri Mast. are as follows: stomata are amphicyclic and occasionally monocyclic, the stomatal frequency is 120.6/mm², the hypodermis is present, there are a large number of filiform sclereids and a few brachysclereids and astrosclereids in the mesophyll, the cuticular projections on the lower surfaces are indistinct. This species differs from all the other species of Cephalotaxus, in which stomata are amphicyclic only, the stomatal frequency is 47.3-88.1/mm², hypodermis is absent except in C. harringtonia and C. harringtonia cv. ‘Fastigiata’, foliar astrosclereids, hrachysclereids asd fibriform selereids may be present or entirely absent, there are distinct cuticular projections on the lower surface. Based upon the above-mentioned features, the gross morphology as well as the alkaloids. Cephalotaxus may be divided into two sections, namely: Sect. Cephalotaxus and Sect. Pectinatae. In addition, also discussed are following problems: the classification of some species in Sect. Cephalotaxus, the suggested subdivision of Sect. Cephalotaxus into 4 series, and the systematic position of Cephalotaxaceae.     

Repetitive cellular patterns in the secondary phloem of conifer and dicot trees,and a hypothesis for their development

Abstract

The radial fusiform cell files of the secondary phloem of conifers and dicots are composed of different cell types?–?fibres, parenchyma and sieve cells (in conifers), or sieve elements plus companion cells (in dicots). These cell types are arranged in characteristic, species-specific sequences along the radii of the files. The sequences are replicated in adjacent files and this leads to tangential bands of similar cell type. Moreover, the sequences are developed repetitively so that a sequence found in one year's growth increment of phloem is repeated in the next increment. In some species, many repetitions of the same sequence occur within one annual increment. A general hypothesis has been developed to account for the radial sequences of cell types. It is proposed that there is a gradient of a phloem-promoting morphogen, a series of morphogen thresholds for the determination of each phloem cell type, and a particular spatio-temporal pattern of periclinal cell division in the phloem domain of the vascular cambium that generates a corresponding pattern of cell displacement through the morphogen gradient in the immediately post-mitotic zone of cell determination. The feasibility of the hypothesis was supported by means of simulation which, using a constant set of initial conditions, could reproduce very nearly all the radial sequences of cell types found in the secondary phloem of a range of species of conifers and woody dicots. The tangential banding of the various cell types suggests that cell production and cell determination are events which occur synchronously across the radial files. The repeating blocks of cell types may constitute functional modules of phloem tissue, and the constituent cells probably have particular patterns of symplasmic connections and mechano-structural properties.     

CO2浓度加倍对辽东栎维管组织结构的影响

 以辽东栎(Quercus liaotungensis)的13年生幼树为材料,分别培养在大气CO2浓度加倍(700μl·L-1)与对照(350μl·L-1)的开顶式熏气室中,研究CO2浓度升高对其茎次生木质部和次生韧皮部结构的影响。结果表明：经CO2浓度加倍处理的两个生长季内,辽东栎的年轮宽度明显增加,为对照的300％～370％,其中晚材宽度的增加更为显著,为对照的750％～830％。另外,晚材中导管的密度和径向直径分别比对照增加50％和20％;木纤维细胞的比例约为对照的170％。但早材的导管分子和木纤维细胞与对照相比均无显著变化。在CO2浓度加倍条件下,辽东栎的次生韧皮部中含晶韧皮薄壁细胞的数目,每条韧皮纤维切向带中韧皮纤维细胞的数目,以及韧皮纤维长度均有显著增加(p≤0.05)。相反地,韧皮纤维细胞的直径和筛管分子长度却无明显变化。值得提出的是,在CO2浓度加倍的条件下,次生韧皮部的宽度、筛管分子的直径、以及每年形成的韧皮部细胞总数分别为对照的82％、87％和80％。综上所述,大气CO2浓度加倍对辽东栎次生木质部的生长发育具明显的正效应,而对次生韧皮部的细胞总数与筛管分子的影响则呈负效应。     

The endophytic system of mediterranean Cytinus (cytinaceae) developing on five host Cistaceae species

BACKGROUND AND AIMS: One of the most extreme manifestations of parasitism is found in the genus Cytinus, a holoparasite whose vegetative body is reduced to an endophytic system living within its host root. There are two species of Cytinus in the Mediterranean, C. hypocistis and C. ruber, which parasitize various genera of Cistaceae, one of the most characteristic families of the Mediterranean scrublands. The aim of this work is to describe the endophytic systems of C. hypocistis and C. ruber, and their tissue relationships with their host. METHODS: Roots from five different hosts infected with C. hypocistis and C. ruber were harvested, and examined by anatomical techniques under light microscopy to elucidate the characteristics of the endophytic system of Cytinus, and to determine if differences in endophytic systems occur between the two species and in response to different hosts. KEY RESULTS: The endophyte structure is similar in both Cytinus species irrespective of the host species. In the initial stages of the endophyte, rows of parenchymal cells spread through the host pericyclic derivatives and phloem, and begin to generate small nodules in the outermost region of the host xylem. Later the nodules anastomose, and bands of parasitic tissue are formed. The host cambium continues to develop xylem tissue, and consequently the endophyte becomes enclosed within the xylem. The bands of parasitic tissue fuse to form a continuous sheath. This mature endophyte has well-developed vascular system with xylem and phloem, and forms sinkers with transfer cells that grow through the host xylem. CONCLUSIONS: The endophytic system of Cytinus develops in all host root tissues and reaches its most mature stages in the host xylem. It is more complex than previously reported, showing parenchyma, xylem and phloem tissues. This is the first report of well-developed phloem in a holoparasitic endophytic species.