THE PALM GYNOECIUM

The morphology, anatomy, and histology of the gynoecia at or close to anthesis are described for 20 genera of palms selected to represent different taxonomic alliances and to include major gynoecial types within the family. Palms may have 1–10 carpels, but most have three. Fifteen genera, including 14 coryphoid palms and the monotypic Nypa fruticans, are apocarpous and the remainder, approximately 190, are syncarpous. Fusion of carpels in some gynoecia begins in the base, in others in the styles. Pseudomonomerous pistils occur in several different alliances: the ovarian parts of two carpels are reduced but three usually equal and functional styles and stigmas are present. The carpel is often follicular in shape with the ventral suture open or, more frequently, partially or completely closed. The carpel may be stipitate or sessile and usually has a conduplicate laminar part. Most carpels are spirally and laterally inserted on the receptacle, but the carpel in some unicarpellate genera (e.g., Thrinax) appears terminal. Stipes, ovarian parts, styles, and stigmas vary in structure and development. Septal nectaries which differ in size, in the presence or absence of specialized canals, and in position, characterize all genera of some groups but only some genera of others. Diverse vascular configurations in the bases of gynoecia vary according to the extent of the floral axis, the development of carpellary stipes, and the connation of the carpels and their adnation to the tip of the floral axis. Four types of carpellary vascular systems are present in the genera described: (1) most palm carpels have three major traces consisting of a dorsal bundle and two ventral bundles, and they may also have up to four pairs of lateral bundles or occasionally more; (2) in certain cocosoid palms no ventral bundles can be distinguished, but a dorsal bundle, many parallel lateral bundles, and a row of immature ventral strands vascularize each carpel; (3) carpels of Phytelephas have a dorsal bundle, two pairs of major lateral bundles and about four pairs of shorter lateral bundles, with no identifiable ventral bundles; (4) carpels of Nypa have many dichotomously branched bundles but none that are recognizable as dorsal, ventral, or lateral strands. Additional peripheral bundles or systems may be present in each of the above types. Ovules are supplied by 1–15 bundles. These are derived either from the carpellary stele; from ventral bundles only; from ventral, lateral, and dorsal bundles; or from a combination of these origins. Certain areas of the gynoecia or certain parts of dorsal carpellary walls in some genera are much less mature at anthesis than surrounding tissues. Implications for floral biology and relationships within the palms and of palms to other groups are discussed.     

A Preliminary Study on the Taxonomy of the Family Magnoliaceae

A new system of classification of Magnoliaceae proposed. This paper deals mainly with taxonomy and phytogeography of the family Magnoliaceae on the basis of external morphology, wood anatomy and palynology. Different authors have had different ideas about the delimitation of genera of this family, their controversy being carried on through more than one hundred years (Table I). Since I have been engaged in the work of the Flora Reipublicae Popularis Sinicae, I have accumulated a considerable amount of information and material and have investigated the living plants at their natural localities, which enable me to find out the evolutionary tendencies and primitive morphological characters of various genera of the family. According to the evolutionary tendencies of the characters and the geographical distribution of this family I propose a new system by dividing it into two subfamilies, Magnolioideae and Liriodendroideae Law (1979), two tribes, Magnolieae and Michelieae Law, four subtribes, Manglietiinae Law, Magnoliinae, Elmerrilliinae Law and Micheliinae, and fifteen genera (Fig. 1 ), a system which is different from those by J. D. Dandy (1964-1974) and the other authors. The recent distribution and possible survival centre of Magnoliaceae. The members of Magnoliaceae are distributed chiefly in temperate and tropical zones of the Northern Hemisphere, ——Southeast Asia and southeast North America, but a few genera and species also occur in the Malay Archipelago and Brazil of the Southern Hemisphere. Forty species of 4 genera occur in America, among which one genus (Dugendiodendron) is endemic to the continent, while about 200 species of 14 genera occur in Southeast Asia, of which 12 genera are endemic. In China there are about 110 species of 11 genera which mostly occur in Guangxi, Guangdong and Yunnan; 58 species and more than 9 genera occur in the mountainous districts of Yunnan. Moreover, one genus (Manglietiastrum Law, 1979) and 19 species are endemic to this region. The family in discussion is much limited to or interruptedly distributed in the mountainous regions of Guangxi, Guangdong and Yunnan. The regions are found to have a great abundance of species, and the members of the relatively primitive taxa are also much more there than in the other regions of the world. The major genera, Manglietia, Magnolia and Michelia, possess 160 out of a total of 240 species in the whole family. Talauma has 40 species, while the other eleven genera each contain only 2 to 7 species, even with one monotypic genus. These three major genera are sufficient for indicating the evolutionary tendency and geographical distribution of Magnoliaceae. It is worthwhile discussing their morphological characters and distributional patterns as follows: The members of Manglietia are all evergreen trees, with flowers terminal, anthers dehiscing introrsely, filaments very short and flat, ovules 4 or more per carpel. This is considered as the most primitive genus in subtribe Manglietiinae. Eighteen out of a total of 35 species of the genus are distributed in the western, southwest to southeast Yunnan. Very primitive species, such as Manglietia hookeri, M. insignis and M. megaphylla, M. grandis, also occur in this region. They are distributed from Yunnan eastwards to Zhejiang and Fujian through central China, south China, with only one species (Manglietia microtricha) of the genus westwards to Xizang. There are several species distributing southwards from northeast India to the Malay Archipelago (Fig. 7). The members of Magnolia are evergreen and deciduous trees or shrubs, with flowers terminal, anthers dehiscing introrsely or laterally, ovules 2 per carpel, stipule adnate to the petiole. The genus Magnolia is the most primitive in the subtribe Magnoliinae and is the largest genus of the family Magnoliaceae. Its deciduous species are distributed from Yunnan north-eastwards to Korea and Japan (Kurile N. 46’) through Central China, North China and westwards to Burma, the eastern Himalayas and northeast India. The evergreen species are distributed from northeast Yunnan (China) to the Malay Archipelago. In China there are 23 species, of which 15 seem to be very primitive, e.g. Magnolia henryi, M. delavayi, M. officinalis and M. rostrata, which occur in Guangxi, Guangdong and Yunnan. The members of Michelia are evergreen trees or shrubs, with flowers axillary, anthers dehiscing laterally or sublaterally, gynoecium stipitate, carpels numerous or few. Michelia is considered to be the most primitive in the subtribe Micheliinae, and is to the second largest genus of the family. About 23 out of a total of 50 species of this genus are very primitive, e.g. Michelia sphaerantha, M. lacei, M. champaca, and M. flavidiflora, which occur in Guangdong, Guangxi and Yunnan (the distributional center of the family under discussion) and extend eastwards to Taiwan of China, southern Japan through central China, southwards to the Malay Archipelago through Indo-China. westwards to Xizang of China, and south-westwards to India and Sri Lanka (Fig. 7). The members of Magnoliaceae are concentrated in Guangxi, Guangdong and Yunnan and radiate from there. The farther away from the centre, the less members we are able to find, but the more advanced they are in morphology. In this old geographical centre there are more primitive species, more endemics and more monotypic genera. Thus it is reasonable to assume that the region of Guangxi, Guangdong and Yunnan, China, is not only the centre of recent distribution, but also the chief survival centreof Magnoliaceae in the world.     

COMPARATIVE MORPHOLOGY OF THE CARPEL IN THE ROSACEAE. III. POMOIDEAE: CRATAEGUS,HESPEROMELES, MESPILUS,OSTEOMELES

The carpels in Crataegus, Hesperomeles, Mespilus, and Osteomeles appear to constitute a morphologically related group: all have bony pits, ovules that tend to be acollateral (usually superposed), and clearly separate ovular and wing bundles, i.e., no “ventral” bundles, at the level of ovular insertion. In species whose carpels have no sutural opening, the integuments are more extensively fused with one another, the degree of intercarpellary fusion tends to be greater, and the carpels are fused with the floral cup to relatively higher levels than in those species whose carpels have a sutural opening. In the few cases in which wing and ovular bundles are adnate at the locular base (Crataegus monogyna, Mespilus, Osteomeles anthyllidifolia, O. Schwerinae), the extent of inter- and extracarpellary fusion and sutural closure is among the most advanced.     

COMPARATIVE MORPHOLOGY OF THE CARPEL IN THE ROSACEAE VI. POMOIDEAE: ERIOBOTRYA,HETEROMELES, PHOTINIA,POURTHIAEA, RAPHIOLEPIS,STRANVAESIA

The pomoid genera, Eriobotrya, Photinia, Pourthiaea, Raphiolepis, Stranvaesia, and Heteromeles, have compound inflorescences and biovulate carpels which become papery at maturity. The carpels of all of these except Heteromeles are fused with one another. There are open sutures in the carpels of Heteromeles, Photinia, Pourthiaea, and Raphiolepis, and in these four genera the extent of fusion of the ovular bundle with the wing bundle is related directly to the state of tegumentary fusion and to the extent of fusion of the carpel with the floral cup. In those species of Eriobotrya and Stranvaesia with closed sutures the integuments tend to be fused, as do the ovular and wing bundles, and the carpels are adnate with the floral cup for a considerable distance; in species with open sutures the integuments tend to be free, the ovular and wing bundles tend to be separate, and the extent of fusion of carpel with floral cup tends to be shorter. In genera with connate carpels the wing bundles of adjoining carpels may also be fused. The greatest extent of fusion occurs in Eriobotrya and Raphiolepis, in which there may also be attenuation and disappearance of the wing bundles above the region of ovular insertion and even reduction and disappearance of the carpellary margin.     

THE TERMINAL IDIOBLASTS IN MAGNOLIACEOUS LEAVES

The idioblasts terminating the foliar veinlets were studied in 152 species of the following magnoliaccous genera: Alcimandra, Aromadendron, Elmerrillia, Kmeria, Liriodendron, Magnolia, Manglietia, Michelia, Paramichelia, and Talauma. In all genera, except Liriodendron, some of the veinlets in mature leaves terminate in enlarged, nonliving cells called tracheoidal elements. Only one wall-facet (rarely 2) in such elements is differentially thickened; this wall lies adjacent to a conventional tracheary element. Ultimate cells of other veinlets in the Magnoliaceae differentiate as thick-walled sclereids, conventional tracheids, clavate tracheids, reticulate-walled dilated tracheids, or secretory cells. The terminal elements differentiate relatively late during leaf enlargement. In the Magnoliaceae, foliar structure is frequently characteristic at the generic level, and in some cases at the species level.     

Comparative floral anatomy and ontogeny in Magnoliaceae

Floral anatomy and ontogeny are described in six species of Magnoliaceae, representing the two subfamilies Liriodendroideae (Liriodendron chinese and L. tulipifera) and Magnolioideae, including species with terminal flowers (Magnolia championi, M. delavayi, M. grandiflora, M. paenetalauma) and axillary flowers (Michelia crassipes). The sequence of initiation of floral organs is from proximal to distal. The three distinct outermost organs are initiated in sequence, but ultimately form a single whorl; thus their ontogeny is consistent with a tepal interpretation. Tepals are initiated in whorls, and the stamens and carpels are spirally arranged, though the androecium shows some intermediacy between a spiral and whorled arrangement. Carpels are entirely free from each other both at primordial stages and maturity. Ventral closure of the style ranges from open in Magnolia species examined to partially closed in Michelia crassipes and completely closed in Liriodendron, resulting in a reduced stigma surface. Thick-walled cells and tannins are present in all species except Michelia crassipes. Oil cells are normally present. Floral structure is relatively homogeneous in this family, although Liriodendron differs from other Magnoliaceae in that the carpels are entirely closed at maturity, resulting in a relatively small stigma, in contrast to the elongate stigma of most species of Magnolia. The flower of Magnolia does not terminate in an organ or organ whorl but achieves determinacy by gradual diminution.     

ONTOGENY AND ANATOMY OF THE FLOWER OF LIMNOCHARIS FLAVA (BUTOMACEAE)

The flowers of Limnocharis flava (L.) Buch. are borne in an indeterminate umbel and each consists of three sepals, three yellow petals, and about 18 carpels surrounded by numerous stamens and staminodia. The androecium is centrifugally developed, and the last-formed members are staminodial; it is supplied by branching vascular systems. Carpels arise almost simultaneously, and a prominent residual floral apex remains. The carpels are partially conduplicately closed and are also primitive in possessing laminar placentation and in lacking differentiation of a style. The gynoecium is essentially apocarpous, but there are slight fusions of adjacent carpels near their ventral margins where they are attached to the receptacle. It is suggested that the Limnocharis flower is the most primitive in the family.     

POLLEN MORPHOLOGY OF THE CHLORAEINAE (ORCHIDACEAE: DIURIDEAE) AND RELATED SUBTRIBES

Pollen organization and morphology of the South American Chloraeinae (Orchidaceae) was examined by scanning electron microscopy and compared with that of the remainder of the otherwise Australasian Diurideae. All five genera of the Chloraeinae, Bipinnula, Chloraea, Codonorchis, Gavilea, and Geoblasta, and at least one genus from each of the other subtribes were sampled. The Australasian Diurideae are diverse in pollen organization and morphology. The two genera of the Acianthinae, Corybas and Acianthus, have very different pollen and their classification is questioned. Monad pollen organization of Pterostylis (Pterostylidinae) is reinterpreted as primitive and not secondarily derived. Pollen of the Chloraeinae is uniform in exine morphology and organization. Most species sampled have reticulate pollen which tends to be foveolate distally. The basic pollen unit of all Chloraeinae is the tetrad, except Codonorchis which possesses monads. Pollen morphology and organization of the Chloraeinae is most similar to the Caladeniinae, which supports the contention that the Chloraeinae including Codonorchis should be retained in the Diurideae.     

木兰科种子内种皮合点区形态及其系统学意义

在扫描电镜下系统研究了木兰科10属52种成熟种子内种皮合点区形态。该形态分为孔型和管型两大类。孔型为内种皮合点区具一小穿孔。木莲属Manglietia、香木兰属Aromadendron、盖裂木属Talauma(8种)、南洋含笑属Elmerrillia和鹅掌楸属Liriodendron具此类型。管型由内种皮合点区向下凹陷形成的小窝和由窝底向外伸出的小管组成。华盖木属Manglietiastrum、盖裂木属Talauma(3种)、长蕊木兰属Alcimandra、含笑属Michelia、合果木属Paramichelia和观光木属Tsoongiodendron具此类型。在木兰属部分种中还观察到两种形态之间的过渡类型。上述形态特征在属内稳定并为木兰科植物所特有,而且明显表现出原始类群的合点区形态大多为孔型,进化类群的合点区形态大多为管型的特点。     

Magnolia cattienensis sp. nov. (Magnoliaceae) from Vietnam

A new species of the family Magnoliaceae, Magnolia cattienensis Q. N. Vu from Cát Tiên National Park, in the Lâm ??ng Province, south of Vietnam is described and illustrated. Magnolia cattienensis is most closely related to M. henryi Dunn, but differs by narrowly cuneate and gradually attenuate bases of the leaves (vs broadly cuneate, not attenuated), pilose pedicles (vs glabrous), and villose peduncles (vs glabrescent), pubescent gynoecium (vs glabrous), and fewer mature carpels (26–30 vs 85–90) with dense trichomes (vs glabrous).     

ANATOMY OF THE GYNOECIUM IN TWO SPECIES OF BAKERIDESIA (MALVACEAE)

Structure of the gynoecium is described in two species of Bakeridesia, subgenus Bakeridesia (Malvaceae, tribe Malveae). The dorsal wall of each carpel bears a winglike projection with a marginal pair of pubescent, bluntly dentate wings. The projection arises as a single, solid ridge of tissue after the ovules are initiated and after the ventral carpellary margins are fused with the receptacle. Two multiseriate layers of fiber-sclereids line each locule and continue into the winglike projection where they are separated by parenchyma. Gynoecial vascularization is described in detail. The richly vascularized carpels are supplied by five traces: a median dorsal trace, which bifurcates into two dorsal bundles; two lateral traces; and two ventral traces. Adjacent ventral traces, lateral traces, and septal bundles are fused—i.e., they are held in common by neighboring carpels. The presence of lateral carpellary traces may be a primitive character in the tribe Malveae.     

A cladistic analysis of Nassauvia Comm. ex Juss. (Asteraceae, Mutisieae) and related genera

FREIRE, S. E., CRISCI, J. V. & KATINAS, L., 1993. A cladistic analysis of Nassauvia Comm. ex Juss. (Asteraceae, Mutisieae) and related genera. Nassauvia and the most closely related genera Calopappus and Triptilion from the southern Andes and Patagonia of South America, form a monophyletic group diagnosed by the following synapomorphies: cypsela trichomes single two-celled, cypsela testa with strengthened cells, pollen grains spheroidal to spheroidal-oblate, colpi membrane with sexine processes, pappus bristles two to six, and pappus deciduous. Furthermore, Nassauvia, Triptilion, and Calopappus form a group with two other Andean genera, Moscharia and Polyachyrus, diagnosed by occurrence of pseudocephalia and a reduction in the number of flowers to five, three or one. A cladistic analysis of the group was undertaken using 35 characters from morphology, anatomy, and palynology. The monophyletic terminal taxa were the 38 species of Nassauvia, the genus Triptilion, the monotypic genus Calopappus, the genus Polyachyrus, and the genus Moscharia. Character polarity was based on outgroup comparison using Cephalopappus. The analysis resulted in 223 equally parsimonious cladograms, each with 70 steps and a consistency index of 0.57. A successive weighting procedure was applied, resulting in 15 cladograms with a consistency index of 0.82. Results of the cladistic analysis support most of the current systematic classification of Nassauvia, with three exceptions: (1) Nassauvia (excluding Calopappus) is paraphyletic; (2) section Masligophorus appears to be a polyphyletic group (N. pygmaea does not cluster with the remaining species of the section); (3) section Panargyrum (without N. lagascae= section Caloptilium) appears to be a paraphyletic group. The capitula arranged in cymose conflorescences in Triptilion are regarded as a primitive condition which gave rise to all stages present in Nassauvia (conflorescence spicate, pseudocephalium, capitula solitary). The capitula arranged in pseudocephalia in Moscharia and Polyachyrus are regarded as a parallel development to the pseudocephalium found in Nassauvia. Nassauvia, subgenus Strongyloma appears as the most primitive taxon, with its spicate conflorescence, whereas section Masligophorus with its solitary capitulum is thought-derived. These results correspond well with cytological data where species of the subgenus Strongyloma have n= 11 and the species of section Masligophorus are tetraploids (n = 22).     

COMPARATIVE MORPHOLOGY OF THE CARPEL IN THE ROSACEAE VII. POMOIDEAE: CHAENOMELES,CYDONIA, DOCYNIA

The multi-ovulate pomoids, Chaenomeles, Cydonia, and Docynia, all have closed sutures and extensive fusion between carpel and floral cup and between ovular and wing bundles. Although the ovules in Docynia are generally apotropic and few in number (4–7), the ovules in the other two genera are pleurotropic and numerous (15–48). A statistical treatment of the whole tribe of Pomoideae shows that in carpels with open sutures ovular and wing bundles definitely tend to be separate while in those with closed sutures these bundles tend to be fused. To a lesser degree carpels with open sutures also tend to have bitegmic ovules, separate carpels, and a lesser extent of fusion between carpel and floral cup, while carpels with closed sutures tend to have monotegmic ovules, united carpels, and a greater extent of fusion between carpel and floral cup.     

Sclerotesta morphology and its systematic implications in magnoliaceous seeds

Seeds of 101 species from 14 genera were observed using stereoscopic and scanning electron microscopy. Sclerotesta morphology is stable within the genera of Magnoliaceae. Two different morphological types are described according to features of the chalazal region, which have great value in classification and have been found only in Magnoliaceae. One is the pore type, characterized by being simple, observed in the relatively primitive taxa of this family, including Manglietia, Pachylarnax, Magnolia (19 species), Aromadendron, Talauma (eight species), Parakmeria (one species), Kmeria (one species), Elmerrillia and Liriodendron . The other one is the tube type, which is characterized by having a more complex structure consisting of a central hollow tube contained within a hole. This type was observed in relatively advanced taxa, including Manglietiastrum, Magnolia (15 species), Talauma (three species), Parakmeria (four species), Kmeria (one species), Alcimandra, Michelia, Paramichelia and Tsoongiodendron . Transitional types between these two were observed in some species of Magnolia . Chalazal region morphology, together with other useful sclerotesta characters, including seed size, shape, the raphal sinus and the external surface of the sclerotesta, may be used as diagnostic characteristics of genera, and even species in Magnoliaceae. A key to identify the different genera is supplied.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 142 , 407–424.     

THE FLORAL ANATOMY OF DIPTERONIA

Hall , Benedict A. (State U. of New York, Cortland.) The floral anatcmy of Dipteronia. Amer. Jour. Bot. 48(10): 918–924. Illus. 1961.—The floral morphology of Dipteronia sinensis closely resembles that of such species of Acer as A. pseudosieboldianum. Both these species share the following characters: (1) complete flowers; (2) functional unisexuality of staminate flowers, resulting from abortion of the pistil; (3) andromonoecious condition, the same tree bearing both perfect and functionally staminate flowers; (4) nectariferous disc, extrastaminal in position. The vascular anatomy of the 2 species, described in detail in this paper, differs only in minor ways, having similar traces supplying, respectively, perianth, androecium and gynoecium. The greatest difference between the 2 genera lies in the form of the mature fruit, which in Dipteronia has the wings of the samaras completely surrounding the seeds; yet in both genera the vascular skeleton of the fruit is essentially the same. There is a similar cohesion of the vascular traces of sepals and petals in both these species. Differences between these and certain other species of Acer such as A. negundo and A. carpinifolium, herein described, greatly exceed those between A. pseudosieboldianum and Dipteronia. The flowers of A. negundo, for example, have undergone extreme reduction from the presumed ancestral type, having no petals or disc and lacking either stamens or carpels. These facts support the inclusion of Dipteronia in the Aceraceae, but make questionable its status as a genus separate from Acer.     

Pollen morphology and ultrastructure of selected species of Magnoliaceae

The pollen morphology and ultrastructure of 20 species, representing eight genera of the Magnoliaceae are described based on observations with light, scanning and transmission electron microscopy. The family represents a homogeneous group from a pollen morphological point of view. The pollen grains are boat-shaped with a single elongate aperture on the distal face. The tectum is usually microperforate, rarely slightly or coarsely rugulose. Columellae are often irregular, but well-developed columellae do occur in some taxa. The endexine is distinct in 14 species, but difficult to discern in the genera Parakmeria, Kmeria and Tsoongiodendron. Within the aperture zone the exine elements are reduced to a thin foot layer. The intine has three layers with many vesicular-fibrillar components and tubular extensions in intine 1. The symmetry of the pollen grains, shape, type of aperture and ultrastructure of the intine show a remarkable uniformity in the family. Nevertheless there is variety in pollen size, ornamentation and the ultrastructure of the exine. The pollen of Magnoliaceae is an example of an early trend of specialization, and supports the view that Magnoliaceae are not one of the earliest lines in the phylogeny of flowering plants.     

The floral anatomy of Victoria Schomb. (Nymphaeaceae)*

The vasculature and development of the flower of Victoria Schomb. are described. The vasculature is basically similar to that found in other genera of the Nymphaeaceae sensu stricto (e.g. Nymphaea L. and Nuphar Sm.). The early development of the flower is similar to that of a hypogynous flower, but meristematic activity shifts from the apex to the periphery in the form of an intercalary ring meristem. The innermost appendicular organs, including the gynoecium, arise by differentiation of tissues formed by this intercalary ring meristem. Evidence is assembled from the mature vasculature and developmental studies: (a) to refute Troll's interpretation that receptacular strips of tissue occur between the carpels and that the outer ovary wall is totally receptacular; (b) to propose that the occurrence of epeltate carpels in Victoria, as correctly described by Troll, has been phylogenetically ‘read’ in the wrong direction; (c) to propose that the flower of Victoria has evolved by (1) the adnation and connation of the proximal portions of the appendicular organs which now envelop the syncarpous gynoecium and (2) the concomitant condensation from a primitive ranalian floral apex.     

POLLEN MORPHOLOGY AND SYSTEMATIC RELATIONSHIPS AMONG NEW WORLD SPECIES IN TRIBE ANTIRRHINEAE (SCROPHULARIACEAE)

The morphology of mature pollen grains among 12 New World genera in tribe Antirrhineae has been examined with light and scanning electron microscopy. Pollen from 29 American species have mean polar diam that range from 17 to 26 μm, have a tectate structure with perforate, microreticulate, or reticulate surface pattern, and are subspheroidal to prolate, and trizonocolporate with fusiform or narrowly oblong colpi that are free or occasionally fused at the poles. Among the genera, pollen size is positively associated with style length but not haploid chromosome number. Three major morphological categories are recognized based on grain shape, exine structural pattern, and colpus shape. Two of these morphotypes each characterize individual genera (Mohavea, Linaria). The other morphological category includes ten New World genera and has been divided into three subcategories based on variation in lumina diam and intermittent occurrence of fused colpi. Only Antirrhinum and Pseudorontium have species or populations with pollen in more than one subcategory. Concordance of morphological, anatomical, chromosomal, and palynological data suggests that Linaria and Mohavea are best placed in separate subtribes from other native American genera. Compared to Old World taxa in tribe Antirrhineae, the most common pollen type (subspheroidal, microreticulate, apocolpate, fusiform colpi) may be the most primitive. Pollen grains with fused colpi (Antirrhinum p.p., Pseudorontium) and perforate (Mohavea) or reticulate (Holmgrenanthe) structural patterns probably represent derived types.     

STUDIES OF PALEOZOIC FERNS: TUBICAULIS STEWARTII SP. NOV. AND EVOLUTIONARY TRENDS IN THE GENUS

Eggert , Donald A. (Yale U., New Haven, Conn.) Studies of Paleozoic ferns: Tubicaulis stewartii sp. nov. and evolutionary trends in the genus. Amer. Jour. Bot. 46(8): 594–602. Illus. 1959.—Tubicaulis stewartii, a new species of the order Coenopteridales is described. The specimen was derived from the Upper Pennsylvanian of Berryville, Illinois, and is characterized by having a lacunar middle cortex, a well-developed integumentary system bearing uniseriate hairs, and xylem parenchyma organized into vertically anastomosing strands. In addition, multiseriate (somewhat transitional to reticulate) bordered pitting is present in the petiolar metaxylem elements, while those of the stem stele are multiseriate scalariform. The habit is intermediate between that of a form such as Osmunda and a tree fern, having an upright tapering stem which gives off prominently decurrent petioles in a 2/5 divergence. A reinvestigation of the type specimen of the most closely allied species, T. multiscalariformis, of Upper-Middle Pennsylvanian age, has shown that it has similar features in the cortex, metaxylem, and integumentary layers. Tubicaulis multiscalariformis and T. stewartii form a distinct group in the 6 species now known, whose evolution has most likely involved the retention of a more primitive form of pitting (multiseriate scalariform) with parenchymatization of the xylem. The remaining species of the genus have not developed xylem parenchyma but have developed circular bordered pitting. The relationships of the genus to other genera in the Coenopteridales remain obscure.     

A PHYTOCHEMICAL APPROACH TO THE GLEICHENIACEAE

The Gleicheniaceae, containing approximately 120 species, is a family of primitive ferns distributed throughout most of the tropics and subtropics. Historically the family was considered to be monogeneric; however, most recent authors using morphological, anatomical and cytological information have subdivided the group into 5 or 6 distinct genera. Some authors have even elevated certain species to family or ordinal levels (e.g., Platyzoma and Stromatopteris). The distribution of flavonol-3-0-glycosides supports the segregation of the Gleicheniaceae, sensu lato, into at least three groupings. Flavonoids similar to those identified within the Psilotaceae (flavones, biflavones, and C-glycosylflavones) were not detected during this study.