Rhomboid Crystals Research Articles

Tumoral calcium pyrophosphate dihydrate deposition disease: Cytopathologic findings on fine-needle aspiration

Tumoral calcium pyrophosphate dihydrate deposition disease (CPPD) is a rare non-neoplastic entity which mimics primary or metastatic soft-tissue or skeletal malignancy. Fewer than a dozen cases have been reported in the literature with only histologic descriptions. We present cytologic findings of a unique case of CPPD in a 73-year-old black female with a history of end-stage renal disease. A fine-needle aspiration (FNA) was done on a 4 x 4-cm neck mass which was clinically thought to be malignant. Cytopathologic examination showed numerous macrophages with markedly distended cytoplasm and containing multiple yellowish-orange, short rhomboid crystals. These were strongly birefringent on polarized microscopy, consistent with CPPD crystals.

Tophaceous pseudogout (tumoral calcium pyrophosphate dihydrate crystal deposition disease)

Most cases of calcium deposition seen radiologically in soft tissues are caused by calcium hydroxyapatite and occur either as a complication of trauma with associated necrosis (eg, fat necrosis), generalized connective tissue diseases (eg, scleroderma), metabolic disturbances (eg, hyperparathyroidism, familial hyperphosphatemia), sarcoidosis, myeloma, or metastases. Hydroxyapatite deposits are seen at many soft tissue sites, including joint capsules, ligaments, blood vessels, dermis, etc. On the other hand, deposits of calcium pyrophosphate are seen typically in the meniscus, articular cartilage, ligamentum flavum, and intervertebral disc. They usually are punctate or linear in distribution within the meniscus or parallel to the subchondral bone end plate. We report seven cases of massive focal calcium pyrophosphate dihydrate (CPPD) crystal deposition disease (tophaceous pseudogout) that occurred in atypical locations for CPPD. The ages of the patients ranged from 31 to 86 years (average, 60.7 years). One patient was male and six were female. The temporomandibularjoint was involved in three patients and the metatarsophalangeal joint of the great toe was involved in two patients. The hip joint and cervical spine were involved in one patient each. A mass or swelling with or without pain was a common symptom. None of the patients in our series had clinical or radiographic evidence of CPPD crystal deposition disease in any other joints. Roentgenograms showed calcified lesions with a granular or fluffy pattern. Histologically, the lesions showed small or large deposits of intensely basophilic calcified material containing needle shaped and rhomboid crystals with weakly positive birefringence characteristic of CPPD. Foreign body granulomatous reaction to the CPPD deposition was constantly found. Chondroid metaplasia around and in the areas of CPPD deposition was observed commonly. Some of the chondroid areas showed cellular atypia in chondrocytes suggestive of a malignant cartilage tumor. It is important to recognize this rare form of CPPD crystal deposition disease and to identify the CPPD crystals in the calcified deposits, thus avoiding the misdiagnosis of benign or malignant cartilaginous lesions.

Isolation of Bacillus thuringiensis from Stored Tobacco and Lasioderma serricorne (F.)

Bacillus thuringiensis was isolated from dried tobacco residues and dead tobacco beetles (Lasioderma serricorne (F.); Coleoptera: Anobiidae) collected in a large number of locations worldwide. Eighty-eight samples of stored tobacco were analyzed and yielded 78 B. thuringiensis strains which were characterized on the basis of parasporal crystal morphology, sodium dodecyl sulfate-polyacrylamide gel electrophoresis profiles, and the results of an immunoblot analysis of the insecticidal crystal proteins. Flagellar antigen identification was used to differentiate selected isolates. Strains that produced rhomboidal crystals associated with the Coleoptera-specific pathotype (Cry III group) were the most abundant strains (59% of the isolates). Preliminary toxicity assays were performed with L. serricorne larvae, and the results suggested that activity is not restricted to isolates related to the Coleoptera-specific group. The results of our survey indicate that B. thuringiensis is part of the natural microflora in the stored-tobacco environment and that this special habitat represents a source of B. thuringiensis isolates that may be used to control stored-product pests.

Structure and Function of the DNA-Dependent RNA Polymerase of Sulfolobus

Summary The DNA-dependent RNA polymerase of the thermophilic archaeon Sulfolobus acidocaldarius (RNAP, EC 2.7.7.6) was shown to consist of thirteen components ranging in size from 122 kDa to approximately 5 kDa. They were named B, A′, A″, D, E, F, G, H, I, K, L, M and N. The staining intensities indicate that they occur in an equimolar ratio. The complexity of the enzyme resembles that of eucaryal RNA polymerases. Most RNAP components and two subassemblies containing the components D plus L and E plus I could be separated in electrophoresis on a cellulose acetate support. The D-L subunit-complex exhibited a typical yellow colour with an absorbance maximum of 400 nm. Inductive coupled plasma mass spectroscopy showed the absence of heavy metal atoms in this complex, but the presence of two zinc ions per RNAP molecule. The subunit G is phosphorylated. The component F was separated into five subspecies differing in charge density. By anion exchange chromatography an F-free RNAP and five variants, each containing a different F-component (F5 to F1 were separated. Renaturation of total dissociated RNAP led to an activity recovery of up to 30%. On this basis experiments to reconstitute a functional enzyme from the separated subunits were done. The components A″, E, H and K appeared to be required for the basic activity of the RNAP. Crystallization of the RNAP yielded needle shaped and rhomboid crystals of a size of up to 0.5 mm. Only F-containing RNAP could be crystallized, but no x-ray diffraction was obtained so far. Genes encoding small subunits of the RNAP of S. acidocaldarius were compared to genes of small components of the eucaryal polymerases A (I), B (II) and C (III). Subunit K was shown to be homologous to the eucaryal component ABC23, N to ABC10s and L to AC19. No homologies to bacterial subunits were found. The components E, F and G have so far no bacterial or eucaryal counterparts. In contrast to the genes of the subunits H, B, A′ and A″, which are transcribed jointly, the genes encoding the smaller subunits were transcribed separately. A further hint to a close relationship between archaeal and eucaryal transcription machinery was the discovery of a gene directly downstream of subunit L, which had a high similarity to the eucaryal transcription factor TFIIS. In vitro transcription of the 16S/23S rRNA-promoter of S. shibatae, the promoter of transcript 3 of the Sulfolobus virus SSV1 and of mutant derivatives with a cell-free extract or with purified RNAP of S. shibatae showed that the RNAP is able to recognize the correct start site by itself and independent of Box A, whereas with a cell-free extract the start point of transcription was determined by the position of box A. We conclude that one or more factors present in the cell-free extract are involved in box A directed transcription-initiation.

Calcium pyrophosphate dihydrate deposition disease: morphological and microanalytical features

The light microscopic and polarization appearances of calcium pyrophosphate dihydrate crystal deposits in tissues are reviewed. In routine sections haematoxylinophilic crystalline deposits with a feathery or brush-like pattern are typical of calcium pyrophosphate dihydrate. Short rhomboidal crystals showing positive birefringence are seen on polarization; X-ray microanalytical and infrared spectroscopic data support the specificity of these appearances. The appearances of the crystal deposits in decalcified specimens are also described. We include six cases of calcium pyrophosphate dihydrate deposition within periarticular bone; to the best of our knowledge this has not previously been described.

Leaf anatomy of Bruniaceae: ecological, systematic and phylogenetic aspects

CARLQUIST, S., 1991. Leaf anatomy of Bruniaceae: ecological, systematic and phylogenetic aspects. Quantitative and qualitative data are given for 60 species of the 12 genera of Bruniaceae; most data are based on liquid-preserved material. Leaves of Bruniaceae are basically linear (broader forms are probably derived) with an apicula that contains phellogen activity. Most bruniaceous leaves have some degree of isolateral construction, with transition to normal bifacial construction in a few species, but more commonly transition to ‘inverse’ bifacial structure (stomata on adaxial face, palisade on abaxial face). The latter type is correlated with the tendency for leaves to be appressed to stems. Tannins and very likely other dark-staining materials are very characteristic of mesophyll cells. Six genera have a large strand of fibres on the midvein and rhomboidal crystals in bundle sheath cells. The other six genera have few or no fibres on veins and have druses in mesophyll cells (but not in bundle sheath cells). These distinctions may relate to intrafamilial taxonomy, but they also support the primitive position usually accorded to Audouinia, Thamnea and Tittmannia. A key to genera based on leaf antomy is offered. Details of epidermal cell shape, cuticular relief and trichome form and structure based on scanning electron microscopy are given. Leaf anatomy, combined with other features, favours a relationship between Bruniaceae and Grubbiaceae in particular and in broader contexts allies Bruniaceae to rosalean and possibly hamamelidalean families.

Acidophilic Macrophage Pneumonia in Laboratory Mice

Acidophilic macrophage pneumonia, characterized by an accumulation of characteristic crystalloid-laden alveolar macrophages, was seen in 30/7,500 NMRI, 7/600 T x HT, 2/100 C57BL and in no cases of 1,500 CBA and 1,100 BALB/c mice. Histologically, there was a focal accumulation of large numbers of eosinophilic macrophages, generally associated with granulocytes. Macrophages could be mononucleate or multinucleate and had a crystalline cytoplasm. Free-lying crystals were sometimes observed. Ultrastructurally, macrophages had a cytoplasmic accumulation of needle-shaped and rhomboidal crystals, often showing a clear lattice structure with a repeat of 3-5 nm. The crystalloid inclusions may be derived from the breakdown products of granulocytes and appear similar to inclusions in macrophages in other parts of the hematopoietic system. That these inclusions are probably derived from eosinophils is based on the appearance within macrophages of structures resembling eosinophil granules at various stages of degradation and the similarity between the lattice repeat of the crystalloids and that of the crystalline core of the eosinophil granule. The crystalloid inclusions may be related to the Charcot-Leyden crystals found in human beings.

The effect of cholesterol on the morphology and reactivity of the mixture of lipids used in syphilis serology

The effect of increasing amounts of cholesterol on the morphology of the liposomes constituting the VDRL-antigen was studied. The morphological parameters examined were the shape of the lipoidal particles and especially the number of lamellae on each particle in the various mixtures of lipids studied. Cholesterol in the presence of cardiolipin and lecithin is observed as rhomboid crystals, indicating that the majority of the cholesterol is located exterior to the lamellar membranes of lecithin and cardiolipin. It is shown that the effect of cholesterol is to reduce the number of individual lamellae per liposome, mainly by mechanically dispersing the cardiolipin and lecithin on the surface of the cholesterol crystals. It is suggested that cholesterol has no effect on the structure of the epitopes which react with antibodies in sera from patients with syphilis, but that, as a result of the mechanical dispersion of cardiolipin and lecithin, it creates liposomes with more accessible epitopes.

Isolation and characterization of EG2158, a new strain of Bacillus thuringiensis toxic to coleopteran larvae, and nucleotide sequence of the toxin gene.

A novel strain of Bacillus thuringiensis was isolated from soybean grain dust from Kansas and found to be toxic to larvae of Leptinotarsa decemlineata (Colorado potato beetle). The strain (EG2158) synthesized two parasporal crystals: a rhomboid crystal composed of a 73116 dalton protein of approximately 30 kDa. Plasmid transfer and gene cloning experiments demonstrated that the 73 kDa protein was encoded on an 88 MDa plasmid and that the protein was toxic to the larvae of Colorado potato beetle (CPB). The sequence of the 73 kDa protein, as deduced from the sequence of its gene (cryC), was found to have regions of similarity with several B. thuringiensis crystal proteins: the lepidopteran-toxic P1 proteins of var. kurstaki and berliner, the lepidopteran- and dipteran-toxic P2 (or CRYB1) protein of var. kurstaki, and the dipteran-toxic 130 kDa protein of var. israelensis. While B. megaterium cells harboring the cryC gene from EG2158 synthesized significant amounts of the 73 kDa CRYC protein, Escherichia coli cells did not. The cryC-containing B. megaterium cells produced rhomboid crystals that were toxic to CPB larvae.

Structural chemistry of titanium and aluminium bimetallic hydride complexes VI. Molecular structure and physico-chemical properties of (η 5-C 5 H 5) 2Ti(μ 2-H) 2 Al(Cl) (μ 2 -H) 2Ti(η 5-C 5H 5) 2, a catalyst-precursor for hydrogenation in the [(η 5-C 5H 5) 2TiCl] 2-LiAIH 4 system

The complex (Cp 2Ti) 2AlH 4Cl has been isolated from the catalytic system (Cp 2TiCl) 2-LiAlH 4, which is a precursor of the catalyst for the hydrogenation and isomerization of olefins. This complex has been studied by X-ray diffraction. The complex forms rhomboidal crystals with unit cell dimensions a = 10.414, b = 11.998, c = 16.008 Å, space group P2 12 12 1, Z = 4, and density ϱ calc = 1.40 g/cm 3. The Cp 2Ti moieties are linked to the Al atom via double hydrogen bridges; the Cl atom is bonded to the Al atom. Analysis of the EPR spectral data and some chemical properties of (Cp 2Ti) 2AlH 4Cl solutions has led us to suggest a mechanism for the formation of the catalytically active species upon interaction of this compound with olefins and solvating solvents.

Crystal-associated cholangiohepatopathy and photosensitisation in lambs.

Four outbreaks of hepatogenous photosensitisation occurred in weaned lambs in north eastern Victoria during the summers of 1985 and 1986. Attack rates varied between 7% and 43% and case fatality rates between 60% and 71%. Clinical signs included photosensitisation and jaundice. Serum biochemistry suggested hepatobiliary and hepatoparenchymal damage with impaired renal function. At necropsy livers were an ochre colour and kidneys a mottled brown to khaki. Histopathologically, needle-shaped to lenticular clefts were observed in and around bile ducts and in hepatocytes, hepatic sinusoidal macrophages and renal tubules. Optically active rhomboidal crystals were present in bile sediments. Panicum schinzii was identified as a possible cause in 2 of the 4 outbreaks. The clinical disease was reproduced in 2 of 6 lambs grazed on a toxic paddock. The disease was indistinguishable from geeldikkop except for the fact that Tribulus terrestris was not present on any of the 4 farms.

Adenosine Triphosphatase Activity of Crystalline Inclusions in Alveolar Soft Part Sarcoma: An Ultrahistochemical Study of a Case

A case of alveolar soft part sarcoma was studied by light and electron microscopy and by electron microscopic enzyme histochemistry of adenosine triphosphatase (ATPase) and 5'nucleotidase(5'Nase). The tumor showed distinct alveolar pattern and diastase resistant PAS positive crystalline inclusions were found in the cytoplasm. Ultrastructurally, characteristic rhomboid crystals and dense granules were observed and they were positive for Mg++- and Ca++-ATPases but negative for 5'Nase. Tumor cell membrane also showed positive activity of ATPase in addition to 5'Nase. These results would support the myogenous derivation of alveolar soft part sarcoma.

Immunocytochemical localization of renin in juxtaglomerular cells.

The involvement of various organelles in the synthesis, transport, and packaging of renin in the juxtaglomerular cells of newborn mice has been investigated by immunocytochemistry with the protein A-gold technique. Highly specific rabbit antibodies against mouse submandibular renin were used. Mild fixation and embedding in glycol methacrylate allowed enough sensitivity to identify a steep gradient of labeling from rough endoplasmic reticulum to Golgi complex to secretory granules. Routine fixation and embedding in Epon produced labeling differentials that allowed delineation of hitherto ill-defined types of secretory granules and vacuoles. The classical pattern of synthesis, transport, and packaging of secretory proteins involves the rough endoplasmic reticulum and Golgi complex and seems to apply to renin secretion. Immunoreactive renin is packaged as rhomboid crystals at the trans face of the Golgi complex. The limiting membrane of these rhomboids fuses to form coalescing protogranules where the crystals eventually yield their individuality maturing into secretory granules. Vacuoles containing a flocculent material, with or without a dense core, show significant immunocytochemical labeling. These vacuoles are not associated with the Golgi complex but occupy cytoplasmic areas well endowed with rough endoplasmic reticulum. As judged from their morphological features and their immunoreactivity, the vacuoles do not seem to follow the sequence of events typical of protogranules and coalescing protogranules. They possibly represent a parallel pathway of renin synthesis and transport, involving the nuclear envelope and bypassing the Golgi complex.

Wood Anatomy of Staphyleaceae: Ecology, Statistical Correlations, and Systematics

Summary Wood of Staphyleaceae is characterized by vessels which are mostly solitary; vessel elements are long with scalariform perforation plates (mostly more than 20 bars per plate) and with scalariform, opposite, or alternate lateral wall pitting. Imperforate tracheary elements range from fiber-tracheids with fully bordered pits somewhat less dense than those of tracheide (Euscaphis, Staphylea, Turpinia) to fiber-tracheide with reduced borders on pits (Huertea) to libriform fibers (Τapiscia) . Axial parenchyma is mostly abaxial, with tendencies towards vasicentric scanty and ray-adjacent cells and only a few diffuse cells. Rays are both multiseriate and uniseriate. Heterogeneous Type IIA. The multiseriate portion of multiseriate rays is often not sheathed with upright cells and consists of procumbent cells which often have bordered pits on radial walls. Rhomboidal crystals, tyloses, and dark-staining amorphous deposits are found in some but not all species. Quantitative features show wood of Staphylea to be less markedly mesomorphic than that of the other genera, a fact perhaps related to winter cold. The Mesomorphy index is held to be more useful in analysis of dicotyledon woods and in predicting relationship with ecology than a conductivity formula, because it runs parallel to ecological gradients, takes into account vessel element length (apparently related to embolism localization), and represents degrees of relinquishment of safety as woods become more mesomorphic. Statistical correlation among wood features of Staphyleaceae show vessel element length related to imperforate tracheary element length and to ray height because all of these are linked to fusiform cambial initial length. Correlation between vessel diameter and vessel element length is slightly weaker, as is inverse correlation between vessel diameter and vessel density (where packing constraints tend to enforce a correlation). The genera of Staphyleaceae can be easily characterized by wood anatomy features such as growth ring presence or absence, perforation plate bar number, presence of helical sculpture within vessels, type of imperforate tracheary element, presence of septa in fibers (in which case axial parenchyma is absent), ray dimensions, tylosis occurrence, and crystal presence. Wood of Staphyleaceae most closely resembles that of some Cunoniales (Saxifragales), and resembles that of Sapindales somewhat less.

Pharmacognosy ofAllamandaBark Drugs

AbstractBark samples of Allamanda cathartica L. (Apocynaceae), an indigenous drug of India, Philippines, etc. have been studied. Chemical, histochemical, anatomical, macromorphological and other pharmacognostic information (e.g. ash value, powder study, fluorescence, etc.) has been given. The bark drugs of the species can be distinguished from those of the allied species A. blanchetlii A.DC. by size and frequency of lenticels, cork-anatomy, number of phelloderm layers, size of starch grains, nature of pericyclic fibre patches, depth of secondary phloem. Diagnostic features are: undulated wall of cork cells, absence of latex tubes (cells present), uniformly distributed rhomboidal crystals, positive reactions to alkaloidal and glycosidal tests, dirty green fluorescence of straw-coloured aqueous extracts, and blackish orange fluorescence of brownish yellow alcoholic extracts.

Comparative Light Microscopical and X-Ray Microanalysis Study of Barium Granuloma

A barium granuloma occurring in the gastric wall was examined by various light microscopical methods and with the scanning electron microscope in association with an energy dispersive x-ray spectrometer. Barium sulphate is present in the form of a slightly granular, yellowish and greenish substance within the cytoplasm of macrophages, and shows no birefringence. Needle-shaped and rhomboid birefringent crystals are rich in magnesium and silicon, and most probably present talc crystals, one of the admixtures in common commercial preparations used for contrast x-ray examination of the gastrointestinal tract, rather than crystals of barium sulphate proper as erroneously interpreted in the literature.

Occurrence, composition, and structure of mitochondrial crystals in a hypotrichous ciliate

Studies were made on the crystals formed in the mitochondria of the hypotrichous ciliate Pseudourostyla on incubation in various media. Rhomboidal crystals were found in the matrix of cells in the logarithmic growth phase in standard medium. These crystals were composed of unit cells with two dimensional fringes with 5.0- and 6.4-nm spacings crossing at an angle of 138°. The mitochondrial polysomes and monosomes were located on the matrix side of the inner limiting membrane. The growth and decay of the crystals coincided with those of the mitopolysomes. Three other types of crystalline inclusions (honeycomb, polygonal, square-lattice) were found in the large mitochondria of “over-fed cells”. The honeycomb crystals were composed of hexagonal unit cells aggregated together with a center-to-center spacing of 10 nm. Crystal formation may be initiated by assembly of mitochondrial matrix Material, resulting in stacked circular units. These units then become compact forming hexagonal crystals. During cell degeneration the mitochondria were torn by greatly enlarged honeycomb crystals or polygonal bodies. The rhomboid honeycomb crystals and polygonal bodies could be digested with protease.

A scanning electron microscopic study of the inorganic and organic matrices comprising the mature shell of Amblema, a fresh-water mollusc

The scanning electron microscope has been used to describe the morphology of the mature shell in a fresh-water bivalve. The structure of the organic and inorganic components within the nacre, the myostracum, and the prismatic layer is described. A transitional or intermediate zone, interposed between the prismatic layer and the nacre, was identified. In demineralized samples, the organic component of the nacre was found to consist of parallel matricial sheets interconnected by irregular transverse bridges. The structure of the mineral component of the nacre was found to vary with the method of specimen preparation. With polished-etched samples, brick-like units were seen. When shells were simply broken and fixed in osmium, the layers of nacreous material consisted of fusing rhomboidal crystals of aragonite which demonstrated subconchoidal fractures. On the inner surface of the shell, the rhomboidal crystals showed an apparent spiral growth pattern. The myostracum was characterized by regions of modified nacreous structure consisting of enlarged aragonite crystals with a pyramidal morphology. The peripheral aspect of the muscle scars was characterized by rhomboidal crystals, the latter fusing to form the typical nacreous laminae. The uniqueness of the anterior adductor scar is exemplified by the presence of pores, each pore walled by pyramidal units, for the insertion of adductor fibres. In most regions of the shell, the prismatic layer consisted of one prism unit thickness with a height of approximately 225–250 μm. However, in two specialized regions of the shell, this layer was seen to consist of multiple layers of stacked prisms. The organic matrices of the prismatic layer are arranged in a honeycomb-like arrangement and packed with mineralized spherical subunits.

A scanning electron microscope and microradiographic study of closure of human coronal dentinal tubules related to occlusal attrition and caries

Mendis and Darling (1979) studied the closure of dentinal tubules in relation to occlusal attrition by microradiography. An investigation of similar teeth using scanning electron microscopy (SEM) has now been carried out and includes the dentinal tubules involved in cervical toothbrush abrasion and dental caries. Thirteen canine teeth were used for SEM of occlusal attrition. Nine were fractured transversely and 4 longitudinally. For caries, 11 teeth were studied by optical microscopy and microradiography and 5 by SEM. Two examples of toothbrush abrasion were examined by SEM. Volume fraction analysis of SEM photographs of occlusal attrition showed that the pattern of tubule closure was similar to that from microradiography. In longitudinal fractures of attrition, the tubules at the worn surface were completely occluded. Below the zone of closure, the tubules were lined by peritubular dentine as in normal dentine but much of the tubular lumen was filled with cuboid or rhomboid crystals of various sizes. In SEM of caries, most of the tubules of the translucent zone were closed. The amount of peritubular dentine was similar to that in normal non-carious dentine and the remaining lumen was occluded by a rod-like plug of granular structure not continuous with peritubular dentine. In abrasion, SEM of longitudinal fractures showed the surface was homogeneous with completely occluded tubules. Beneath this surface layer, most tubules were empty. The findings were consistent with the earlier microradiographic ones.

Wood anatomy of the dicotyledons indigenous to New Zealand

Abstract The wood anatomy of Paratrophis microphylla (Raoul) Ckn. and P. banksii Cheesem. is described. Main stemwood of P. microphylla and branchwood of P. banksii was examined. The woods are diffuse-porous with slightly distinct to distinct growth rings. Vessels are often solitary in P. microphylla whereas in P. banksii they are frequently arranged in radial multiples. Vessels have simple perforation plates, and alternate, angular intervascular pits. Tyloses are sometimes present. Pits leading to rays are simple or with narrow borders. They are large, round, and radially to axially elongated. Axial parenchyma is abundant, and occurs in various forms, i.e., paratracheal bands, terminal, aliform confiuent, vasicentric, scanty paratracheal, unilaterally scanty paratracheal. Fusiform parenchyma cells are sometimes present. Abundant intercellular spaces are associated with paratracheal bands and aliform confiuent parenchyma. Rays are noded, heterogeneous types III and II, and 1–10 cells wide. Rhomboidal crystals are sometimes more numerous in axial parenchyma and rays in P. banksii than in P. microphylla. Fibres are very thin to thin-walled with simple to slightly bordered pits present mainly on radial walls. Crystal-bearing fibres are occasionally present in P. banksii. A few anatomical differences which were observed in P. banksii and P. microphylla may have a limited diagnostic value.