Subsidiary cells in the Orchidaceae: their general distribution with special reference to development in the Oncidieae

Subsidiary cell formation in leaves of the Oncidieae begins with the production of a trapezoid cell on each side of the guard cell mother cell. The trapezoid cells are formed by oblique divisions in the tiles of cells next to the tile of cells containing the guard cell mother cell. The trapezoid cell usually divides unequally to form a subsidiary cell and a derivative cell. The subsidiary cell is smaller and next to the guard cell mother cell. The derivative cell enlarges and is often indistinguishable from the other epidermal cells. Rarely, polar subsidiary cells are also formed. In very rare cases the smaller of the division products of the trapezoid cell divides to form two subsidiary cells next to each guard cell. Subsidiary cells have been found in all tribes of the epidendroid and vandoid groups, all neottoid tribes examined except the Orchideae, and the subfamily Cypripedioideae. The absence of subsidiary cells in primitive genera of the epidendroid tribes and the presence of subsidiary cells in the most advanced genera of the epidendroid and vandoid groups supports the hypothesis that the presence of subsidiary cells is an advanced condition in the Orchidaceae.     

Systematic and comparative anatomy of Cymbidieae (Orchidaceae)

Cymbideae comprise an assemblage of 28 genera nearly all of which are represented in this study. Their anatomy is relatively homogenous with the exception of Govenia , in which roots lack velamen and pseudobulb vascular bundles lack sclerenchyma, conditions that do not obtain in other genera. Marginal fibre bundles in leaves of Grammatophyllum and Porphyroglottis consist of clusters of thicker-walled, narrower, epidermis-facing fibres as well as thinner-walled, wider, mesophyll-facing fibres. This feature also occurs in some species of Maxillaria . Baculate tilosomes appear in the roots of a majority of genera in Cymbidieae, as they do in species of Maxillaria , confirming DNA analyses showing a close relationship between tribes Cymbidieae and Maxillarieae. Govenia is singled out both on anatomical and molecular grounds as being ill-placed in Cymbidieae. Cladistic analysis produces only a few tentative hypotheses of phylogenetic relationships among the 28 genera, showing that anatomical characters are of limited value in assessing affinities within this tribe. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 139 , 1–27.     

The superior olivary complex in C57BL/6 mice.

The cellular and cytoarchitectural features of the lateral superior olive, the medial superior olive, the superior paraolivary nucleus and the medial, lateral and ventral nuclei of the trapezoid body are described in C57BL/6 mice using Nissl, Bodian and Golgi techniques. Principal, spindle and marginal cells are present in a well-defined lateral superior olive. The dendrites of these cells run primarily within rostrocaudal sheets as in the cat. The principal cells of the medial nucleus of the trapezoid body are similar to the principal cells in the cat. Large multipolar cells characterize the lateral nucleus of the trapezoid body and bipolar cells with a medial-lateral orientation are found in the medial superior olive. The largest neurons are found in the superior paraolivary nucleus and the lateral superior olive, and the medial and ventral nuclei of the trapezoid body. While brain weight and neuronal packing density change with development, the characteristic location of cell groups and the shape and Nissl-staining pattern of neurons in the youngest brains examined were essentially unchanged in the adult mice, although dendritic maturation had occurred. The homologies of the C57BL/6 superior olivary complex nuclei with the same areas described in other mouse strains, rat and cat are discussed. This study expands our understanding of the organization of the superior olivary complex in an inbred strain of Mus musculus and relates it to other species. The data about changes occurring during postnatal maturation may aid in the interpretation of behavioral and physiological studies of neonatal plasticity of the auditory system.     

Biphenanthrene from Stanhopea lietzei (Orchidaceae) and its chemophenetic significance within neotropical species of the Cymbidieae tribe

Orchidaceae are one of the largest families of flowering plants. In this work, the first phytochemical study of the non-flowering parts of the South American species Stanhopea lietzei (Regel) Schltr. is reported. It led to the isolation of nine compounds, including the rare dimeric compound 2,2′,7,7′-tetramethoxy-4,4′,6,6′-tetrahydroxy-(1,1′)-biphenanthrene (1). This compound was tested for the first time against HeLa human cancer cells, with IC₅₀ 16.9 ± 0.9 μg/mL. Biological assays against neotropical parasites, virus and other human cancer cell lines are also reported. Finally, the relevance of biphenanthrenes, flavonoids, and C-glycosylated phenolic compounds for chemophenetics relationships within neotropical species of the Cymbidieae tribe and Oncidiinae, Maxillariinae, Cyrtopodiinae and Stanhopeinae subtribes was also discussed.     

Earliest orchid macrofossils: Early Miocene Dendrobium and Earina (Orchidaceae: Epidendroideae) from New Zealand

Fossil leaves of two Early Miocene orchids (Dendrobium and Earina) are reported from New Zealand. The distinctive, raised tetra- to cyclocytic stomatal subsidiary cells of Earina and characteristic papilla-like absorbing glands and "ringed" guard cells of Dendrobium support the placement of the fossils into these genera. These therefore represent the first Orchidaceae macrofossils with cuticular preservation, the oldest records for subfamily Epidendroideae, as well as the first New Zealand and southern hemisphere fossil records for Orchidaceae. These taxa belong in basal clades to the Vandeae/Cymbideae or Epidendreae (Earina) and the Australasian clade of Dendrobium sensu lato. This phylogenetic placement demonstrates expansion of epiphytic orchids into Zealandia by the mid-Cenozoic and an important role for southern continents in the diversification of Orchidaceae.     

Cuticle micromorphology of leaves of Pinus (Pinaceae) in east and south-east Asia

Cuticle micromorphology of 21 species of Pinus in east and south-east Asia was studied with scanning electron microscopy and leaf morphology was described. Cuticle characters that can be distinguished by their size, shape, and surface texture, as well as by the number of subsidiary cells, the rows of epidermal cells within a stomatal band, the number of cells between stomata in stomatal rows, and the patterns of cuticular flanges are described in detail. Most of these characters have not been considered in sufficient detail previously. Some of the inner cuticular features, such as the texture of periclinal walls, the shape of the top of the anticlinal walls, the comparative size of the lateral and polar subsidiary cells, and the development of the groove near bristles, are diagnostic characters for subgenera. The agreement between cuticle characters and taxa is discussed. Cuticular characters were used to try to resolve the position of taxa that currently appear in different places in different classifications.     

Cuticle micromorphology of leaves of Pinus (Pinaceae) from Mexico and Central America

Cuticle micromorphology of 34 taxa of Pinus from Mexico and Central America was studied with scanning electron microscopy, and leaf morphology was described. In total, 29 characters, 22 from the inner cuticular surfaces and seven from the outer, were described in detail. These characters have value either for testing infragenerie classifications or for identifying individual taxa. Characters relating to the periclinal wall texture of the epidermal cells, the shape and degree of development of the anticlinal walls of the epidermal cells, the basal and apical shapes of anticlinal epidermal cell walls, the continuity of the epidermal cells, the size ratio of the polar to lateral subsidiary cells, the grooves on subsidiary cells, the cuticular flanges between guard and subsidiary cells, the groove near the bristles and the elevation of the Florin ring ridge and striations on the Florin ring are particularly useful for infrageneric classification. The agreement between these characters and infrageneric classifications is discussed. Characters relating to the end wall shapes of the epidermal cells, the relative length of epidermal cells, the shape of the stomatal apparatus, the texture of guard and lateral subsidiary cell surfaces, the polar extensions, the number of subsidiary cells and epidermal cell layers between stomatal rows, the integrity of stomatal rows, cell numbers between stomata in a row, cuticular flanges between guard cells, bristle flanges and surface textures, epicuticular waxes, striations on Florin rings and stomatal shapes, contain some important information for identifying Mexican pines. The distribution of the states of each character is compared with that of the Asian pines. Cuticular characters are used to help determine the affinities of taxonomically difficult taxa.     

国产省藤属植物的叶表皮形态学

对国产省藤属（Calamus L．）植物17种2变种的叶表皮进行光学显微镜观察,除单叶省藤（C.simplicifolius）、短叶省藤（C.egregiw）和白藤（C.tetradactylus）外,其它种均为首次报道。省藤属植物的叶表皮形态较为一致,气孔器为轮列4细胞型（tetracytic,或称四轮列型）,即有4个副卫细胞,其中2个为侧副卫细胞,2个为端副卫细胞;表皮细胞为长方形,纵向排列。表皮毛有3种类型：多细胞排成单列的单毛（人喙省藤C．macrorrhynchus）、多细胞排成2-3列的单毛（毛鳞省藤ethysanolepis等）、多细胞分枝毛（白藤等）。表皮细胞的长度和宽度特征、细胞壁的厚薄及波纹的深浅和形状、端副卫细胞的长短等细微特征在种问存在差异,可以区分种类。叶表皮结构还反映了种问的亲缘关系。因此,叶表皮特征对于省藤属种类的划分和亲缘关系的确定有较大的分类学意义。     

Epidermal Structures and Stomatal Ontogeny in Some Mimosaceae

The structure of trichomes and stomata on leaflets of 21 speciesof the Mimosaceae are described. Non-glandular trichomes inMimosa pudica are of three types: unicellular, with a roundedthick-walled base and a terminal unicellular body, and multicellular.Capitate, clavate, or cylindric, 3–6-celled glandularhairs are observed on leaflets of Mimosa pudica only. Leafletsare amphistomatic in all species except Adenanthera pavonina,Calliandra sp., Parkia biglandulosa, Pithecellobium dulce, andSamanea saman in which they are hypostomatic. Only paracyticstomata are found in Leucaena leucocephala and Mimosa pudica.In the rest stomata are of more than one type. In spite of thediversity, the most frequent type in these species is paracytic.Anisocytic stomata, in all cases, are secondarily derived fromparacytic ones by transverse or oblique wall formation in asubsidiary cell. Similarly some stomata with one subsidiarycell are also secondary derivatives of the paracytic ones becauseof one of the subsidiary cells assuming the form of an epidermalcell. The development has been traced in 14 species and thatof paracytic stomata may be mesogenous or mesoperigenous, thatof stomata with one subsidiary cell mesogenous but anomocyticstomata are ontogenetically perigenous. Occasionally a meristernoidis cut off from one of the subsidiary cells of a paracytic stoma.The organization of a stoma from such a meristemoid has beentraced.     

On Cordaites neimengensis sp. nov from Lower Permian of Zhungeerqi,Inner Mongolia, China

The leaf cuticle of Cordaites neimengensis sp. nov was studied by light and scanning electron microscopy. The specimens were collected from kower Permian of Zhungeerqi, Inner Mongolia (Neimenggu), China. Comparing with other species of Cordaites, it was a new species of the genus, based on the structure of its epidermis. Cordaites neimengensis sp. nov (Pis. Ⅰ to Ⅲ; Text-fig.l,B) The specimen comprises two incomplete leaves over 16 cm in length. One is about 1.4 cm wide at the lower part and 0.3 cm wide at the upper part, with nearly 29 veins per cm and 3 to 5 interstitials. The width of the other leaf is about 7.5 cm at the lower part and 8.2 cm at the upper part with 25 veins per cm and 3 to 5 interstitials. Epidermis amphistomatic. Epidermal cells of upper cuticle aligned in longitudinal rows, nearly rectangular in shape, about 33.6 to 86.4 pm x 10.2 to 28. 8 pm in size. Stomatal apparatus consisting of 2 sunken guard cells surrounded by 2 lateral and 2 polar subsidiary cells. Stomata haplocheillic, about 56.2 pm x 45.5 pm in size, usually arranged in short chains, with one polar subsidiary cell (usually 23.1 to 25.4 pm wide, 34.1 to 39.2 pm long in size) shared with 2 consecutive stomata. The polar subsidiary cells round, oblong or rhomboid in shape. The guard cells reniform or bean-shaped, usually 9.7 to 11.6 pm wide, 23.4 to 29.1 pm long in size. Density and index of stomata about 18/mm2 and 3.2%, respectively. Epidermal cells of lower cuticle also nearly rectangular in shape, about 62.4 to 144 pm × 9.6 to 16.8 pm in size. Stomata on the lower cuticle, haplocheillic, 40.8 pm wide and 48 pm long in size, with a pair of sunken guard cells, which is bean-shaped and surrounded by 2 lateral and polar subsidiary cells. Stomata arranging in parallel bands, typically one, sometimes two. As for the latter, a single row of lateral subsidiary cells (9.2 to 14.4 pm wide, 33.6 to 62.4 pm long in size) is shared with 2 parallel rows of stomata and occasionally also in bands with two rows side by side. In view outside, small papillae on the outer periclinal wall as well as the lateral subsidiary cells. In view inside, some folds along the anticlinal wall but flat about the periclinal wall. Nonstomatic bands usually with 1 to 10 rectangular cell rows. Density and index of the stomata about 209/mm2 and 27.2 %, respectively. 1401%-type: 9342; locality: Heidaigou of Zhungeerqi; Inner Mongolia, North China; Age: Lower Pennian (Shanxi Formation).     

Three-Dimensional Reconstruction of the Stomatal Complex in Pinus canariensis Needles Using Serial Sections

Abstract: The three-dimensional (3D) morphology of the stomata in leaves of Pinus canariensis is described with respect to the spatial arrangement of guard cells, subsidiary cells, polar and lateral cells. Serial semi-thin sections of the stomatal apparatus were digitally reconstructed and analysed with regard to the position, shape and size of the cell types involved. The stomatal complex consists of 16 cells with uniquely shaped polar and lateral cells. The polar cells form a kind of roof above the epistomatal chamber thereby reducing the surface aperture. The structural features of the stomatal complex differ from other Pinus species and are presumed to be an adaptation to extreme environmental conditions.     

Identification of K(+) channels in the plasma membrane of maize subsidiary cells

The stomatal complex of Zea mays consists of two guard cells with the pore in between them and two flanking subsidiary cells. Both guard cells and subsidiary cells are important elements for stoma physiology because a well-coordinated transmembrane shuttle transport of potassium and chloride ions occurs between these cells during stomatal movement. To shed light upon the corresponding transport systems from subsidiary cells, subsidiary cell protoplasts were enzymatically isolated and in turn, analyzed with the patch-clamp technique. Thereby, two K(+)-selective channel types were identified in the plasma membrane of subsidiary cells. With regard to their voltage-dependent gating behavior, they may act as hyperpolarization-dependent K(+) uptake and depolarization-activated K(+) release channels during stomatal movement. Interestingly, the K(+) channels from subsidiary cells and guard cells similarly responded to membrane voltage as well as to changes in the K(+) gradient. Further, the inward- and outward-rectifying K(+) current amplitude decreased upon a rise in the intracellular free Ca(2+) level from 2 nM to the micro M-range. The results indicate that the plasma membrane of subsidiary cells and guard cells has to be inversely polarized in order to achieve the anti-parallel direction of K(+) fluxes between these cell types during stomatal movement.     

海南莎草属植物叶下表皮微形态的研究

利用光学显微镜对海南莎草属(Cyperus Linnaeus)15个种1个变种的叶下表皮微形态进行了研究。结果显示:(1)该属叶下表皮微形态基本特征如下:长细胞为长筒形、短筒形,少数为近方形,边缘波状、深波状;无短细胞的存在;副卫细胞为高圆屋顶形、圆屋顶形、圆屋顶至三角形或三角形;(2)根据保卫细胞的形态将海南莎草属分为两大类型即保卫细胞两端明显加厚型和保卫细胞两端不明显加厚型;(3)海南莎草属叶下表皮微形态一致,表明莎草属是一个自然类群,但在莎草属种间叶下表皮的长细胞形态、保卫细胞及副卫细胞形态、气孔长宽等存在一定的差异,可作为本属种间分类鉴别的参考依据。     

STRUCTURE AND ONTOGENY OF THE STOMATAL COMPLEX IN PINUS STROBUS L. AND PINUS BANKSIANA LAMB.

The morphology of the stomatal complex in Pinus strobus L. and P. banksiana Lamb, is described and it is proposed that the stomatal complex should be considered an eight-celled complex consisting of two guard cells, and two polar, two lateral, and two hypodermal subsidiary cells. An ontogenetic study found these cells closely related developmentally. It was also found that the stomatal complex in these two pines could not readily be classified as haplocheilic because a polar subsidiary cell arises from the same protodermal cell as does the guard cell mother cell. A modification of the classical concept of stomatal development was necessary to describe the stomata as eumesoperigenous.     

A Scanning Electron Microscopic Observations of the Leaves in Some Conifers

Scanning electron microscopic observations of the leaves in some conifers are described. These are hyplocheilie stomata surrounded by different morphological subsidiary cells. In Keteleeria, the lateral wall of larger subsidiary cells possesses prom.inant eutieular globoides. Cuticular semigloboides between the sinuoms epidermal anticlinal walls are most obvious in other epidermis. However the single laver of cushion cells which looated underneath the guard ceils of the abaxial epidermis in Cathaya is discovered. The mesophyll ceils with incurved walls of Cathaya consist mainly of single layer of flat oubical cells flat longi-cubieal cells as of the polytriehaeeous lamcllae, thus it may be designated as mesolamellae. It not only supports the establishment of Cathaya Chun and Kuang as a new genus of the Pinaeeae but also may be another important biosystematical evidence between Cathaya and Pinus. The distribution and polymorphism of foliar solereids in Amentotaxus which are different from leaves of other gymnosperms described. The transfusion tracheids are also different in some ways from other genera.     

台湾岛和海南岛兰科植物区系特征比较

为探明台湾岛和海南岛兰科( Orchidaceae)植物区系特征,在充分查阅相关资料的基础上,对2个岛屿兰科植物的物种组成、生活型和分布区类型进行分析,并对这2个岛屿与大陆陆地和周边国家兰科植物的分布特征进行比较和分析。结果表明：2个岛屿的兰科植物共有146属639种,其中,台湾岛有107属446种,海南岛有96属302种。2个岛屿树兰亚科( Subfam. Epidendroideae)的属和种比例均最高;原始的拟兰亚科( Subfam. Apostasioideae)在台湾岛无分布,而在海南岛分布有2属4种。从属和种的数量看,含1种和2~5种的属比例较高,分别占台湾岛兰科植物总属数的43.9%和36.4%,占海南岛兰科植物总属数的45.8%和40.6%;且包含种数多的属的比例较低。从生活型看,2个岛屿地生兰和附生兰的比例较高,分别占台湾岛兰科植物总种数的52.7%和34.3%,占海南岛兰科植物总种数的37.1%和55.3%。从分布区类型看,台湾岛和海南岛的兰科植物分别可划分为11和10个分布区类型,且均以热带亚洲至热带大洋洲分布型属和种的比例最高,热带亚洲分布型属和种的比例也较高。从热带成分与温带成分的数量比(R/T)看,台湾岛和海南岛兰科植物属的R/T值分别为3.6和3.3,种的R/T值分别为10.9和11.9,说明2个岛屿的兰科植物均以热带成分为主,台湾岛还包含一定的温带成分。从共有属和共有种看,2个岛屿与大陆陆地的兰科植物共有属均约占各自兰科植物总属数的90.7%,其中,三地共有属有66属;台湾岛与大陆陆地的兰科植物共有种比例较低(46.2%),而海南岛与大陆陆地的兰科植物共有种比例较高(74.9%),说明2个岛屿与大陆陆地兰科植物属的同源性较高,且海南岛兰科植物的大陆性特征更明显。与周边国家相比,2个岛屿与越南的兰科植物共有种比例较高,分别占台湾岛和海南岛兰科植物总种数的33.9%和75.2%。综合分析结果显示：台湾岛和海南岛的兰科植物种类丰富,生活型齐全,且具有明显的热带性质,但台湾岛的兰科植物还表现出一定的温带性质;2个岛屿与大陆陆地兰科植物的亲缘关系较近,但台湾岛兰科植物的特有性更明显。     

Comparative anatomy of Sirhookera (Orchidaceae) growing in Western Ghats of southern India

We compared the anatomical characteristics of vegetative organs, peduncle and mycorrhizal morphology of the two known species of Sirhookera (Epidendroideae, Orchidaceae) to identify anatomical markers for identification and the ecological adaptations of these species. The leaves are hypostomatic bearing tetracytic stomata and the walls of subsidiary cells are smooth in Sirhookera lanceolata and undulate in Sirhookera latifolia. On the adaxial and abaxial surfaces the leaves are covered by a thick cuticle. The hypodermis is dimorphic and present on both sides of the leaf; chlorenchyma is homogenous and the vascular bundles are collateral. The rhizome of Sirhookera possesses a single-layered epidermis, thick cuticle, thin-walled parenchymatous ground tissue containing starch grains and scattered collateral vascular bundles. A thick-walled sclerenchymatous band separates the cortex from the parenchymatous ground tissue comprising of banded cells in the peduncle. Starch grains are present in the ground tissue of the S. latifolia peduncle. The roots consist of the velamen, ∩-thickened exodermis, thin-walled cortex consisting of water-storage cells, O-thickened endodermis and a vascular cylinder with parenchymatous pith. Starch grains are present in the root cortical cells of S. lanceolata but absent in S. latifolia. Fungal pelotons that aids in nutrient acquisition were observed in the root cortical region of both species. The study revealed significant differences between the anatomical characteristics of the two species and that most of the anatomical features of Sirhookera relate to their ecological adaptations.     

Variation in the structure and development of foliar stomata in the Euphorbiaceae

The structure and ontogeny of foliar stomata were studied in 50 species of 28 genera belonging to 17 tribes of the family Euphorbiaceae. The epidermal cells are either polygonal, trapezoidal, or variously elongated in different directions and diffusely arranged. The epidermal anticlinal walls are either straight, arched or sinuous. The architecture of cuticular striations varies with species. The mature stomata are paracytic (most common), anisocytic, anomocytic and diacytic. Occasionally a stoma may be tetracytic, cyclocytic or with a single subsidiary cell. The ontogeny of paracytic stomata is mesogenous dolabrate or trilabrate, mesoperigenous dolabrate; that of diacytic stomata is mesogenous dolabrate, whereas that of anisocytic stomata is mesogenous trilabrate; rarely an anisocytic stoma may be mesoperigenous. Hemiparacytic stomata are mesoperigenous unilabrate; tetracytic stomata are mesoperigenous dolabrate and anomocytic stomata perigenous. Abnormalities encountered include four types of contiguous stomata, stomata with a single or both guard cells aborted and persistent stomatal initials. Cytoplasmic connections between the guard cells of two adjacent stomata or the guard cell of a stoma and an adjacent epidermal/subsidiary cell, or both types occurring in a species, were noticed. The stomatal development, distribution, diversity and basic stomatal type with reference to systematics are discussed.     

The genus Eugenia L. (Myrtaceae) in southern Africa: the structure and taxonomic value of stomata

The mature stomatal morphology of 11 southern African species of Eugenia , and also of E. uniflora L. (naturalized) and E. incerta Diimmer (a garden plant of unknown origin) has been studied by light and scanning electron microscopy.
Leaves of all the species are hypostomatic and water-stomata are occasionally present. Two different stomatal types, X and Y, differing mainly in their cuticular ornamentation, were found in the southern African species. The grouping of species based on stomatal characters supports a previous grouping of species on the basis of periderm and seed characters.
Conspicuous lipid bodies, usually present in the subsidiary cells, are limited to the southern African species. Although the subsidiary cells do not differ in shape and size from adjacent epidermal cells, their contents often have a higher tannin content than ordinary epidermal cells. The variable patterns of arrangement of the three to five subsidiary cells makes it difficult to identify the stomata with existing classifications based on mature topography. Thus, a new term 'anomostaurocytic' is proposed for the stomatal type found in the southern African species.
Stomata of E. uniflora and E. incerta are paracytic and anomocytic respectively, and the cuticular ornamentation of their stomata differs from those of the southern African species. The view that E. incerta is not closely related to the southern African species is supported by differences in its cuticular ornamentation, lack of lipid bodies in the subsidiary cells, anomocytic stomata and prominent T-pieces at the guard cell poles.     

A SYSTEMATIC STUDY OF ENDOTHECIAL THICKENINGS IN THE ORCHIDACEAE

Endothecial cell thickenings were examined in anther macerations of representative species from 210 genera of the Orchidaceae. Nearly all species examined possessed the characteristic thickened walls which, in several tested species, gave a positive reaction to phloroglucinol, indicating the presence of lignin. Four basic thickening types were identified; distribution of the types was found to be largely in agreement with previously recognized suprageneric groups. Type I thickenings are tightly packed channels of loops or helices and were found in the “neottioid” genera, the Apostasioideae, and putatively basal genera in the remaining subfamilies. Because of its occurrence in the Apostasioideae, which is believed to be the most basal subfamily, Type I is hypothesized to be the plesiomorphic thickening type for the remainder of the Orchidaceae. Type II thickenings appear as scattered loops and may be a synapomorphy for the Orchidoideae, as they were found in all genera sampled from the subfamily except Disperis. Type III thickenings are circular in appearance and were found in the Cypripedioideae and in some members of the Spiranthoideae and Epidendroideae. Type IV thickenings show little regular arrangement, appearing to be scattered bars, and were observed primarily in the Epidendroideae and also in some Spiranthoideae. Three subtypes were recognized in Type III and Type IV. Some genera, such as Triphora, Goodyera, and Elythranthera, had thickenings that appeared intermediate between the recognized types. In general, terrestrial genera were found to have regularly arranged, well-developed thickenings, while many epiphytic groups showed congested, irregular, thinner thickenings.