Mouth Of Tube Research Articles

Airflow resistance measurement for a layer of granular material based on the Helmholtz resonance phenomenon.

A Helmholtz resonance technique was employed to predict the airflow resistance of layers of granular materials, namely glass beads, brown rice, soybean, adzuki beans, and corn kernels. Each granular sample was placed on the tube mouth of an open-type Helmholtz resonator. The resonant frequency was determined by measuring the electric impedance of a loudspeaker that was installed in the resonator and driven by a chirp signal linearly sweeping from 90 to 220Hz for 6.0 s. For a changing sample layer thickness, the resonant frequency was measured, and the specific airflow resistance was calculated by measuring the static pressure drop required for N2 gas to flow through the layer at a constant velocity of 0.042m/s. When the thickness of the layer was fixed, the Helmholtz resonant frequency decreased as the specific airflow resistance increased, regardless of the kind of granular material.

Effect of ZnS layers on optical properties of prepared CdS/TiO2 nanotube arrays for photocatalyst

The TiO2 nanotube arrays (TiO2 NTAs) prepared by re-oxidation were chosen as basement. The NTAs prepared through re-oxidation show smoother surface and more uniform tube mouth on large scale compared with the first as-grown one. We use successive ionic layer adsorption and reaction method to deposit quantum dots (ZnS and CdS) onto the sample successively. The findings reveal that two kinds of quantum dots (∼10 nm) distribute regularly and the nanotube mouth is open. From the UV–Vis absorption spectrum of samples, the red shift occurs after the sedimentation of the two quantum dots, which proves that the double modification can expand the absorption to 650 nm. Among all specimens, the sample produced by co-deposition has the highest speed of catalytic efficiency of 90.7% compared with bare TiO2 NTAs (52.9%) and just CdS QDs sensitized sample (65.8%). In the test of photocatalysis durability, the decay percentages of CdS/TiO2 NTAs and ZnS/CdS/TiO2 NTAs were 35.8 and 48.4%, respectively, which means that the ZnS passivation layer plays a crucial role in enhancing photocatalytic activities.

Formation, Evolution, and Extinction of Standing Waves in Evaporation from Pores.

We report on the formation, evolution, and extinction of standing waves (SWs) detected by infrared measurements at the upper region of a curved meniscus interface pinned at the mouth of a horizontally positioned capillary pore. The SWs are clear and strong in acetone but absent in ethanol for both tube sizes investigated (1-2 mm diameter). Dependent upon the tube size and the initial liquid filling ratio, the SWs start sooner for a lower filling ratio. The intriguing experimental observation is that the SWs disappear at a specified liquid length between the receding meniscus and the one pinned at the tube mouth, which seems to depend strongly upon the tube size and independent of the initial liquid filling ratio. The origin of the SWs could be due to the strong interaction between surface tension and gravity, which also generates oscillatory periodic Marangoni flow in the meniscus liquid phase.

Optimal shape of entrances for a frictionless nanochannel

In a nearly frictionless channels such as narrow carbon nanotubes, flow is limited by the viscous dissipation occurring at the tube mouth. Using both numerical and analytical approaches, it is demonstrated that such end effects can be reduced to a considerable extent by adding an entrance of well-chosen shape.

Tailoring the Blast Exposure Conditions in the Shock Tube for Generating Pure, Primary Shock Waves: The End Plate Facilitates Elimination of Secondary Loading of the Specimen.

The end plate mounted at the mouth of the shock tube is a versatile and effective implement to control and mitigate the end effects. We have performed a series of measurements of incident shock wave velocities and overpressures followed by quantification of impulse values (integral of pressure in time domain) for four different end plate configurations (0.625, 2, 4 inches, and an open end). Shock wave characteristics were monitored by high response rate pressure sensors allocated in six positions along the length of 6 meters long 229 mm square cross section shock tube. Tests were performed at three shock wave intensities, which was controlled by varying the Mylar membrane thickness (0.02, 0.04 and 0.06 inch). The end reflector plate installed at the exit of the shock tube allows precise control over the intensity of reflected waves penetrating into the shock tube. At the optimized distance of the tube to end plate gap the secondary waves were entirely eliminated from the test section, which was confirmed by pressure sensor at T4 location. This is pronounced finding for implementation of pure primary blast wave animal model. These data also suggest only deep in the shock tube experimental conditions allow exposure to a single shock wave free of artifacts. Our results provide detailed insight into spatiotemporal dynamics of shock waves with Friedlander waveform generated using helium as a driver gas and propagating in the air inside medium sized tube. Diffusion of driver gas (helium) inside the shock tube was responsible for velocity increase of reflected shock waves. Numerical simulations combined with experimental data suggest the shock wave attenuation mechanism is simply the expansion of the internal pressure. In the absence of any other postulated shock wave decay mechanisms, which were not implemented in the model the agreement between theory and experimental data is excellent.

Pressure retaining method based on phase change for coring of gas hydrate-bearing sediments in offshore drilling

Coring of gas hydrate-bearing sediment with situ-pressure retained is significant for both geophysics and geochemistry. However, the core recovery of current pressure corers is relatively low, which is attributed to the sensitivity of mechanical valves to solid particles and drilling cuttings. To improve the core recovery of the pressure corers, the pressure retaining method based on the phase change of situ drilling fluid has been used to seal the core tube mouth. The pressure retaining capacity of the ice valves made from seawater mixed with different mass concentrations of bentonite was tested; the influence of the ice valve length and freezing temperature on the pressure retaining capacity was also studied. Results show that the ice valve made from pure seawater could not retain pressure for the fissures caused by stress because of the temperature difference and the incompletely freezing of the ice valve caused by the concentrated inorganic salts in the core of the ice valve. The ice valve made from seawater mixed with 7% mass concentration of bentonite can sustain pressures of up to 47MPa. Both high ice valve length and low freezing temperature are beneficial for improving the pressure sustaining capacity of the ice valve. Results indicate that using the ice valve made from seawater mixed with bentonite to instead mechanical valves in the pressure corer can be a potential solution to improve the recovery of pressurized hydrate-bearing sediment core.

Transport properties of simple organic molecules in a transmembrane cyclic peptide nanotube.

Multiple molecular dynamics simulations have been performed to explore the transport properties of single methane, methanol, and ethanol molecules through the water-filled transmembrane cyclic peptide nanotube (CPNT) of 8 × (WL)₄-POPE, as well as the potential application of this CPNT in the separation of an alcohol/water mixture. Molecular size and hydrophilicity/hydrophobicity were found to significantly influence molecular diffusion behavior in the channel. Methane and ethanol display more explicit distributions in midplane regions, while methanol mainly occurs in α-plane zones. Methane and ethanol drift faster near an α-plane zone, whereas methanol diffuses uniformly throughout the whole transmembrane region. The dipole orientation of channel methanol is significantly affected by the bare carbonyl groups at the tube mouths and flips mainly in gap 4, whereas the rotation of ethanol is blocked. Ball-shaped hydrophobic methane experiences more flips in gap 4. The PMF (potential of mean force) profiles of the three organic molecules disclose their different diffusion behaviors in the CPNT. Amphiphilic alcohols are able to form direct H-bonds with channel water and the tube. Both single and double water bridges with the tube were observed in the methanol and ethanol systems. The different adsorption behaviors of the alcohols and water in the dehydrated CPNT may lead to the potential application of the CPNT as a means of separating alcohols from water.

Systematics of the southern African genus Ixia L. (Iridaceae): 5. Synopsis of section Ixia, including five new species

The southern African winter-rainfall genus Ixia L., with almost 100 species, is divided into four sections, with sect. Ixia distinguished by a filiform perianth tube closely clasping the style, and filaments that occlude the mouth of perianth tube and are sometimes partly united but never decurrent in the tube. The section was last revised by G. J. Lewis in 1962, at which time it included 18 species and several varieties. Five species have since been described, I. atrandra Goldblatt & J.C. Manning, I. calendulacea Goldblatt & J.C. Manning, I. frederickii M.P. de Vos (subsequently reduced to synonymy in I. dubia Vent.), I. mostertii M.P. de Vos and I. superba Goldblatt & J.C. Manning. One more, I. purpureorosea G.J. Lewis, was later transferred to sect. Hyalis (Baker) Diels. Here we provide a revised key and synopsis of sect. Ixia as the final contribution in our series of systematic studies in the genus, which already includes revisions of sects. Dichone (Salisb. ex Baker) Goldblatt & J.C. Manning, Hyalis (Baker) Diels and Morphixia (Ker Gawl.) Pax. We recognize a total of 29 species in sect. Ixia, including five new species: I. alticola Goldblatt & J.C. Manning and I. angelae Goldblatt & J.C. Manning from the central Cedarberg; late-flowering I. helmei Goldblatt & J.C. Manning from near Bot River; I. roseoalba Goldblatt & J.C. Manning from the western Langeberg; and yellow- or pink-flowered, usually stoloniferous I. sarmentosa Goldblatt & J.C. Manning from marshes and seeps at low elevations in Western Cape. We also recognize white-flowered I. leucantha Jacq. (currently a synonym of I. polystachya L.), I. fuscocitrina Desf. ex DC. (currently a variety of I. maculata L.), and elevate I. polystachya var. longistylis M.P. de Vos to species rank as I. longistylis (M.P. de Vos) Goldblatt & J.C. Manning. I. patens var. linearifolia G.J. Lewis and I. viridiflora var. minor M.P. de Vos are reduced to synonymy in their respective species.

A Theoretical Study of Nonlinear Optical Properties for Stilbene Grafted to Carbon Nanotubes

DFT method was used to calculate the equilibrium geometries, electron structures and first-hyperpolarizabilities of grafted SWCNT (4,4) by organic chromophore stilbene at B3LYP/6-31G* level. ZINDO method was also used to calculate first-and second-hyperpolarizabilities. The calculated results show that stilbene graftings make the energy gap a little reduced and the maximum absorption wavelength red shifted, however grafting of stilbene breaks the symmetry of pure nanotube and lets hyperpolarizability increase obviously. We also found that grafting on tube mouth results in better nonlinear for their better conjugation and amide bond-linking shows bigger hyperpolarizabilities relative to direct bond-linking.

The effect of wall thickness and material on Marangoni driven convection in capillaries

Abstract We present results of an experimental investigation of Marangoni convection for an evaporating meniscus in open air pinned at the mouth of a capillary tube. Four different liquids have been studied: ethanol, methanol, acetone and, for the first time, also FC-72. This experimental configuration has been studied before by the present authors and others. However, it is the first time that the effect of the capillary tube thickness and material is experimentally investigated. In particular, the study considered the same internal diameter for all the tubes (1 mm) and three borosilicate external diameters (1.4, 2, and 3 mm) as well as one polycarbonate (1.25 mm) and one sapphire (3 mm). These three tube materials were chosen for their very different thermal properties and their optical transparency. The evaporation rate is measured by tracking the second meniscus receding inside the capillary tube while the first one is pinned at the tube mouth. It was found that the evaporation rate is influenced more by the thermal conductivity of the tubes than the wall thickness. An infrared camera has also been employed to measure the interfacial temperature at the meniscus pinned at the tube mouth and also along the wall of the tube close to the tube mouth. In addition, a heat transfer analysis has been performed at the tube mouth along with a mass transfer analysis which allowed the evaluation of the temperature of the meniscus interface and the evaporation rate, respectively, and comparing these results with the measured ones. The deviation found is maximum 65% between measured and calculated temperature differences between wall and meniscus and 6.7% for the evaporation rate. The results are qualitatively assessed in the light of those obtained for evaporating sessile drops and the trends found are similar.

New species, combinations and range extensions in Hesperantha Ker Gawl. (Iridaceae: Crocoideae) from western South Africa

The southern and tropical African genus Hesperantha, now with some 88 species, is distinguished in subfam. Crocoideae by the style dividing near or below the mouth of the perianth tube into relatively long style branches and, with a few exceptions, by woody corm tunics. We describe three new species from Northern Cape, South Africa discovered in September 2014. Hesperantha palustris (sect. Concentricae) from marshes at high elevation and Hesperantha filiformis (sect. Concentricae) from rocky sites, were both collected on the Hantamsberg. H. palustris is one of the tallest species in the genus, reaching up to 480mm, with moderate-sized white flowers opening after dark. The diminutive H. filiformis, one of only a few species with just three leaves, has a perianth tube slightly longer than the spreading white tepals. The third new species, Hesperantha eremophila, has the flat-based corm of sect. Hesperantha and is restricted to the Vandersterrberg in the Richtersveld National Park. We also recognize Hesperantha falcata subsp. lutea for populations with yellow flowers opening during the day and closing in late afternoon. Typical plants of H. falcata have white flowers opening in the late afternoon. We also record two range extensions: an additional population of the Roggeveld Escarpment endemic, Hesperantha secunda, from the Keiskie Mtns SW of Calvinia; and high altitude populations of Hesperantha rivulicola from 1 380m on the Hantamsberg, otherwise known from lower elevations near Nieuwoudtville and Calvinia (760–980m).

Marangoni convection in evaporating meniscus with changing contact angle

In this work, the Marangoni convection in the liquid phase of an evaporating meniscus interface in open air has been studied for varying contact angles. Ethanol undergoes self-evaporation inside a capillary tube of borosilicate glass with internal diameter of 1 mm. The evaporation is not uniform along the meniscus interface pinned at the capillary tube mouth, and this creates a gradient of temperature between the wedge and the centre of the meniscus. It is this temperature difference and the scale (1 mm) that generate a gradient of surface tension that is acknowledged to drive the vigorous Marangoni convection in the meniscus liquid phase. In previous studies of this configuration, the meniscus has mainly been concave and for this reason, other researchers attributed the differential temperature along the meniscus to the fact that the meniscus wedge is closer to the tube mouth and also further away from the warmer liquid bulk than the meniscus centre. The present study investigates concave, flat and convex meniscus by using a syringe pump that forces the meniscus to the wanted shape. With the present investigation, we want to further demonstrate that it is instead the larger evaporation at the meniscus triple line near the wedge that controls the phenomenon. Flow visualization and infrared temperature measurements have been performed. For concave and convex meniscus, the temperature measurements are in line with the predicted trend; the Marangoni vortices for these two menisci shapes spin in the same direction according to the temperature differences along the meniscus. For a flat meniscus, an intriguing experimental evidence has been found: the temperature difference is inverted with respect to concave and convex menisci, but surprisingly, the Marangoni vortices spin in the same direction than for concave and convex menisci.

Can’t swallow, can’t transfer, can’t toilet: Factors predicting infections in the first week post stroke

Post stroke infections are a significant clinical problem. Dysphagia occurs in approximately half of stroke patients and is associated with respiratory infections; however it is unclear what other factors contribute to an increased risk. This study aimed to determine which factors are most strongly predictive of infections in the first 7days post stroke admission. A retrospective review of 536 stroke patients admitted to Australian hospitals in 2010 was conducted. Data were collected on 37 clinical and demographic parameters. Univariate and multivariate logistic regression analysis was performed. The overall incidence of infection was 21%. Full assistance with mobility and incontinence on admission were associated with increased odds of general infection. Nil by mouth and presence of a nasogastric tube were significantly associated with patients developing respiratory infections. Urinary incontinence was a significant predictor for a urinary tract infection. Incidence of infection was highest on day two post admission. This study found enteral feeding, requiring full assistance with mobility and incontinence were significantly associated with developing infections in acute stroke. It contributes valuable new data from a large cohort of stroke patients demonstrating a period of susceptibility to infection in the very acute post stroke period.

Onset of Marangoni convection in low viscosity silicon oil inside a heated capillary tube

In the present experimental investigation the onset of Marangoni convection inside a heated capillary tube filled with low viscosity silicon oil is presented and discussed. The 1 cSt viscosity silicon oil used evaporates spontaneously at ambient temperature. The evaporation of silicon oil inside the 1 mm internal diameter tube is not uniform, being larger near the meniscus triple line region than in the centre; this creates gradients of temperatures (which have been measured by InfraRed thermography) and therefore of surface tension. For the unheated tubes this gradient of surface tension is found to be not big enough to set a convection motion (Marangoni convection) which was reported by one of the present authors in previous studies using alcohols. With increasing power supplied to the tube by an electric heater, the Marangoni convection sets in and strengthens at increasing powers till the pinned meniscus detaches from the tube mouth and recedes inside the capillary.

Correlation between the replacing time of plasma drainage bag and the bacterial growth rate

Objective To explore the correlation between the replacing time of plasma drainage bag and the bacterial growth rate among orthopaedic surgery patients , and to control or reduce the risk of catheter-related infection.Methods The convenient sampling method was used to select 100 patients with postoperative serum drainage tube and disposable drainage bag , from September 2012 to August 2013.Patients were randomly divided into the control group （group A, 33 cases） and the observation group （group B, 32 cases; group C, 35 cases）.The amount of drainage were recorded every 24 hours of the three groups of patients , and then the drainage bags were emptied .Group A replaced the drainage bag regularly every day; Group B replaced the drainage bag every 48 hours;Group C did not replace the drainage bag .The outside mouth of the drainage tube and the drainage liquid were taken to bacterial culture . The positive rate of bacterial culture , patients’postoperative body temperature and the rate of incision infection were compared within groups .Results Twenty-four hours after operation, the results of bacterial culture among three groups were negative .However, after 48 hours, six patients （18.1%） in group A, two patients （6.4%） in group B showed positive results of the bacterial culture .None of the patients in group C had the positive results .The comparison among three groups was statistically significant （χ2 =10.32,P〈0.05）.After 72 hours, eight patients （24.2%） in group A, two patients （6.4%） in group B showed positive results of the bacterial culture .None of the patients in group C had the positive results.The comparison among three groups was statistically significant （χ2 =11.82,P〈0.05）. The incidence of incision infection of group A , group B and group C were 15.1%（5/33）, 6.3%（2/32） and＆amp;nbsp;0.0%（0/35）, respectively.There was a significant difference among three groups （χ2 =11.18,P〈0.05）.The body temperature of the three groups showed no significant difference （F=7.53,P〉0.05）.Conclusions With the increase of drainage bag replacement frequency , the positive rate of bacterial culture , as well as the drainage bag and drainage tube mouth bacteria culture positive rate increase .Therefore, for orthopaedic patients , the plasma drainage tube and disposable drainage bag should be emptied every 24 hours after the measurement of drainage liquid, but do not have to be replaced every 48 hours or every 24 hours. Key words: Infection; Postoperative care; Replacing time; Plasma drainage bag; Drainage tube; Bacterial growth rate

Respiratory Infections in Acute Stroke: Nasogastric Tubes and Immobility are Stronger Predictors than Dysphagia

Swallowing problems occur in 37-78 % of stroke patients. Evidence points to multiple factors contributing to the development of pneumonia in the first week post stroke, of which the presence of dysphagia is one. A heightened understanding of the very acute phase (first 7 days post stroke) is required to improve management of this population. We conducted a retrospective review of 536 stroke patients admitted to Australian hospitals in 2010. Data were collected on 37 clinical and demographic parameters. Descriptive statistics and univariate and multivariate logistic regression analyses were performed. Dysphagia was present in 58.5 % of admissions. For those patients remaining in the study for the full week there was a recovery rate from dysphagia of 30.5 %. Overall incidence of respiratory infection was 11 %. Respiratory infections developed in 17 % of patients with dysphagia. Impaired Glasgow Coma Scale, ischemic stroke, and significantly impaired mobility were associated with swallowing difficulties. Being nil by mouth and insertion of a nasogastric tube were significant predictors for respiratory infections. This study of a large cohort of acute stroke patients supports research indicating that aspiration pneumonia is multifactorial in nature and the incidence of respiratory infection is significant in the very acute stroke period.

Three-dimensional Marangoni cell in self-induced evaporating cooling unveiled by digital holographic microscopy

A digital holographic microscope has been used to trace the trajectory of a tracer particle inside the liquid phase of an evaporating meniscus formed at the mouth of a 1-mm2 borosilicate tube filled with ethanol. The Marangoni flow cells are generated by the self-induced differential evaporating cooling along the meniscus interface that creates gradients of surface tension which drive the convection. The competition between surface tension and gravity forces along the curved meniscus interface disrupts the symmetry due to surface tension alone. This distorts the shape of the toroidal Marangoni vortex. Thermocapillary instabilities of the evaporating meniscus are reported by analyzing the trajectories of the tracer particle. It is found that the trajectory of the tracer particle makes different three-dimensional loops and every four loops it returns to the first loop. By analyzing several loops it was found that the characteristic frequency of the periodic oscillatory motion is around 0.125 Hz.

Molecular dynamics study of Na+ transportation in a cyclic peptide nanotube and its influences on water behaviors in the tube

The dynamics of Na(+) transportation in a transmembrane cyclic peptide nanotube of 8 × (WL)4/POPE has been simulated. The curve of PMF (potential of mean force) for Na(+) moving through the tube, based on ABF (adaptive biasing force) method, indicates that Na(+) possesses lower free energy in an α-plane region than in a mid-plane one. It was found that Na(+) would desorb one or two water molecules in the first solvation shell when entering the tube and later maintain in a solvation state. The average numbers of water molecules around Na(+) are 4.50, 4.09 in the first solvation shell, and 3.10, 4.08 in the second one for Na(+) locating in an α-plane zone and a mid-plane region, respectively. However, water molecules far away from Na(+) location still nearly arrange in a form of 1-2-1-2 file. The dipole orientations of water molecules in the regions of gaps 1 and 7 display "D-defects", resulted from the simultaneous electrostatic potentials generated by Na(+) and the bare carbonyls at the tube mouths. Such "D-defects" accommodate the energetically favorable water orientations thereby.

New taxa of <i>Hesperantha</i> (Iridaceae: Crocoideae) from the southern African winter rainfall region and a review of the <i>H. pilosa</i> complex

The southern and tropical Africa genus Hesperantha Ker Gawl., now with 85 species, is distinguished in subfam. Crocoideae by the style dividing into relatively long, usually laxly spreading style branches at or shortly below the mouth of the perianth tube (rarely well within the tube or above the mouth of the tube) and, with a few exceptions, by hard, woody corm tunics. We describe three new species here. H. dolomitica Goldblatt J.C.Manning, a narrow endemic of limestone outcrops on slopes north of the Vars River in the Knersvlakte, Western Cape, has the bell-shaped corms characteristic of the small sect. Hesperantha but is distinctive in the section in its pure white perianth with relatively long tube and soft-textured, falcate to distally trailing leaves. H. laxifolia Goldblatt J.C.Manning from the Pakhuis Mtns, Western Cape, stands out in sect. Hesperantha in its prostate, somewhat succulent foliage leaves, and spikes of 2–5 white flowers with unusually short filaments less than 1 mm long and particularly short anthers, ± 4 mm long. The short style branches, ± 4 mm long, remain suberect rather than laxly spreading. H. secunda Goldblatt J.C.Manning from the Roggeveld Escarpment, Northern Cape, has until now been included in H. pilosa but differs in its secund spike of nodding flowers with short style branches, and leaves with broadly winged margins. We also recognize a new subsp. bracteolata (R.C.Foster) Goldblatt J.C.Manning of H. pilosa (L.f.) Ker Gawl. for populations of plants with diurnal flowers with usually blue or purple (occasionally white) tepals lacking dark pigmentation on the reverse. With additional material to hand, we reduce blue-flowered H. ciliolata Goldblatt to synonymy in subsp. bracteolata and report range extensions for H. pilosa subsp. pilosa, now recorded as far east as the Langeberg near Cloete’s Pass.

The Cape genus <i>Micranthus</i> (Iridaceae: Crocoideae), nomenclature and taxonomy

The genus Micranthus (Pers.) Eckl., has traditionally been treated as comprising three species, all with virtually identical, bilaterally symmetric, deep or pale blue to white flowers arranged in crowded, 2-ranked spikes and with divided style branches, but differing in their foliage. Examination of plants in the field and herbarium shows that there are four additional species. M. filifolius Goldblatt J.C.Manning, from the Caledon District of the southwestern Western Cape, has up to six, filiform leaves, the blades of at least the lowermost terete and cross-shaped in section, and usually pale blue-mauve flowers. M. simplex Goldblatt J.C.Manning from high elevations on Zebrakop, Piketberg, has the smallest flowers in the genus, white but tinged lilac as they age, linear leaves up to 1.5 mm wide, and undivided style branches. M. cruciatus Goldblatt J.C.Manning, from the northern Cedarberg and Bokkeveld Mtns, has up to four leaves, the lower with linear or terete blades with heavily thickened margins and central vein and relatively large flowers, unusual in having the style dividing at the mouth of the perianth tube into particularly long branches, these deeply divided as is typical of the genus. M. thereianthoides Goldblatt J.C.Manning, from the Paardeberg south of Malmesbury, is unique in the genus in having flowers with an elongate perianth tube. We also document the occurrence of large populations of putative hybrids at some sites. We provide a complete revision of Micranthus with original observations on leaf anatomy, pollen morphology and reproductive biology and discuss its confused taxonomic and nomenclatural history and that of the three common species of the genus, known for over 150 years. In so doing, we neotypify Gladiolus alopecuroides L. (1756) [= Micranthus alopecuroides (L.) Eckl. (1827)], type of the genus, and choose lectotypes for M. plantagineus Eckl. var. junceus Baker (1892) and Gladiolus fistulosus Jacq. Now with seven species, Micranthus remains endemic to the Cape flora region, extending from its extreme northern limit in the Bokkeveld Mtns south-eastwards to Port Elizabeth. We also deal with the genera Paulomagnusia Kuntze and Beilia Kuntze with which Micranthus has sometimes been associated, although both are nomenclatural synonyms of Thereianthus G.J.Lewis, a genus close allied to Micranthus.