Vegetative Anatomy Research Articles

Studies in Cyperaceae: XVII Novelties inFimbristylis (L.) Vahl and their vegetative anatomy

Two novelties ofFimbristylis collected from Tamil Nadu (Madras State) are described and illustrated. One of them belongs to the sectionFuscae and the other one toCymosae. The vogetative anatomical characters of these two novelties not only fall within the ambit of the range of anatomical variability of the genus as a whole but their respective anatomical features in combination appear to be characteristic and different from those of the species already known anatomically.

Investigations on the life histories of three Farlowia species (Rhodophyta: Cryptonemiales, Dumontiaceae) from Pacific North America

Cultures of Farlowia compressa, F. mollis, and F. conferta, begun with carpospores indicate that all three species have a life history in which upright gametophytes alternate with a crustose tetrasporophyte resembling Haematocelis and/or Cruoriopsis. Tetrasporangia were produced by F. mollis and F. conferta only in 15°C, 8:16 h photoregime. Tetrasporangia were not produced in culture by F. compressa, but field-collected tetrasporophytes with a vegetative anatomy identical to cultured crustose plants released tetraspores forming upright gametophytes. Uprights were initiated only in long-day conditions (15°C, 16: 8 h for F. compressa and F. conferta; 15°C, 16: 8 h and 10°C, 12: 12 h for F. mollis).

Contributions to the Morphology and Anatomy of Strasburgeria and a Discussion of the Taxonomic Position of the Strasburgeriaceae

A comprehensive study of floral and vegetative anatomy of the monotypic New Caledonian genusStrasburgeria Baillon was undertaken to provide a more thorough and accurate generic description, and to help clarify the evolutionary relationships of the plant. Detailed descriptions of leaf, stem, nodal, wood, floral, fruit, and seed morphology and anatomy are presented. In general, vegetative characters are primitive whereas those of the reproductive organs are regarded as advanced or specialized.Strasburgeria is envisioned as an early and independent offshoot from the thealean ancestral stock. It appears that the most appropriate treatment of the genus is to recognize the family Strasburgeriaceae and put it adjacent to the Ochnaceae in the current widely accepted manner.

A morphological and embryological study of Callicoma serratifolia Andr. (Cunoniaceae).

The morphological and anatomical features of Callicoma serratifolia populations on the New England Tablelands reveal the existence of two distinct groups, here designated A and B. Major morphological differences between these groups include leaf margin serration, distribution of hairs on stems and branches, possession of one trichome type in group A in contrast to two types found in group B, overall leaf size and venation patterns. At the anatomical level the differences are in vessel dimensions and the number of bars on perforation plates. Features common to both groups include bisexual, pentamerous and apetalous flowers, tetrasporangiate versatile anthers with a glandular tapetum, simultaneous cytokinesis in pollen mother cells and colporate pollen which is released at the 2-celled stage. The ovules are anatropous, bitegmic and crassinucellate with a polygonum type of embryo sac development. The endosperm is of the nuclear type. Both integuments contribute to the formation of the seed coat. The embryo is straight. While in its vegetative anatomy C. serratifolia resembles members of the families Eucryphiaceae, Saxifragaceae and Escalloniaceae, embryologically it closely resembles Baueraceae and less closely the subfamily Hydrangeoideae of the Saxifragaceae.

COMPARATIVE ANATOMY AND MORPHOLOGY OF PS1LOXYLON AND HETEROPYXIS, AND THE SUBFAMILIAL AND TRIBAL CLASSIFICATION OF MYRTACEAE

SummaryEvidence from wood, leaf, and floral anatomy, from palynology, and from reconsideration of vegetative and reproductive morphology fully support (1) the placement of Heteropyxis by Fernandes (1971), Stern & Brizicky (1958), and Weberling (1963) in Myrtaceae/Leptospermoideae on the basis of organography, palynology, and petiole and wood anatomy, and (2) the placement of Psiloxylon by van Tieghem (1904) in Myrtaceae on the basis of especially vegetative anatomy. Diagnostic myrtaceous characters shared by both genera include: entire, simple, gland‐dotted, penninerved leaves wth intramarginal veins; rudimentary stipules (Heteropyxis only); pentamery; nectary lining floral tube; imbricate, persistent calyx; many pollen features; sunken styles; baccate or capsular fruits (resp. Psiloxylon and Heteropyxis); exalbuminous seeds; bicollateral bundles; secretory cavities in all aerial organs, including the anthers; unilacunar one‐trace nodes; arcuate petiolar bundles with sclerenchymatous sheaths (only in lamina of Psiloxylon); vestured pits; wood fibers with distinctly bordered pits; and tannin. Both genera, however, differ from many, but not all Myrtaceae in having: alternate leaves; unisexual, but bisexual‐appearing flowers (only the staminate in Psiloxylon); perigyny; few stamens (Psiloxylon diplostemonous, Heteropyxis essentially obdiplostemonous); short style and divided stigma (Psiloxylon only); cancellate seed (Psiloxylon only); and such wood characters as septate, crystalliferous fibers and lack of vasicentric tracheids in Psiloxylon, and lack of axial parenchyma in Heteropyxis. The segregates Heteropyxidaceae and Psiloxylaceae should thus be included in Myrtaceae. The foregoing ensemble of characters conclusively excludes for Heteropyxis any assignment to Rhamnaceae or Rutaceae, for Psiloxylon any assignment to Bixaceae sensu lato, Flacourtiaceae, or Guttiferae, and for both genera an assignment to Lythraceae. Because it would be anomalous in either of the two traditional myrtaceous subfamilies, Psiloxylon is best treated as a new subfamily in Myrtaceae. Finally, since Leptospermeae and Chamaelaucieae differ as much from each other as either does from Myrteae, Chamaelaucieae should be elevated to subfamilial status in Myrtaceae. The family Myrtaceae thus has four subfamilies: Myrtoideae, Psiloxyloideae, Leptospermoideae, and Chamaelaucioideae. An addendum discusses Briggs & Johnson's (1979) detailed paper on vegetative and especially reproductive structure of Myrtaceae.

Studies in Cyperaceæ. — XIX. Novelty in Lipocarpha : L. raynaleana and its vegetative anatomy

Studies in Cyperaceæ. — XIX. Novelty in Lipocarpha : L. raynaleana and its vegetative anatomy

Comparative anatomy and systematics of woody Saxifragaceae. Deutzia*

A comparative account is given of the vegetative anatomy of 33 species and four hybrids of Deutzia. Anatomical evidence supports the retention of section Neodeutzia with Deutzia.

Comparative anatomy and systematics of woody Saxifragaceae. Philadelphus*

A comparative account is given of the vegetative anatomy of 32 species of Philadelphus. The subgcneric classification of the genus by Hu is partially supported by differences in leaf anatomy. The wood of Philadelphus is homogeneous except for the lianous P. mexicanus. Xylem differences between this and other species are attributed to modifications related to the lianous habit.

The affinities ofPlagiopteron suaveolensGriff. (Plagiopteraceae)

Abstract Flower, pollen and macromorphological characters of the monotypic genus Plagiopteron indicate affinities with Elaeocarpaceae (Malvales) and Flacourtiaceae (Violales). The vegetative anatomy can also be interpreted in support of this view but, in addition, indicates a possible affinity with Celastraceae (Celastrales). Inclusion of Plagiopteron as a monotypic family (Plagiopteraceae) in Malvales with a position close to Elaeocarpaceae is recommended. The relationship with Flacourtiaceae, however, suggests a link with Violales.

Comparative studies of vegetative anatomy and morphology of the Gesneriaceae of Sri Lanka

An anatomical and morphological survey has been made of all 13 species of Gesneriaceae in Sri Lanka. Descriptions have been prepared of the leaves, petioles, and stems. Aeschyanthus ceyianica (Trichosporeae) has been found to closely resemble other species in the genus. Anatomically, Didymocarpui and Chirita are apparently closely allied to each other within the tribe Didymocarpeae, while Chamnpionia has several distinctive and interesting features. Rhynchoghssum and Epithema, both assigned to the tribe Klugieae, are less allied anatomically than they appear morphologically. Rhynchotechum (Cyrtandreae) shows features in keeping with its distinct taxonomic position. The possible significance of this type of comparative study is discussed.

Studies in Cyperaceae: XVI. Novelties inCyperus Linn. and their vegetative anatomy

Three novelties collected from Tamil Nadu (Madras State) are described and illustrated of which one belongs to the sectionSulcati and the other one toFlavescentes of the subgenusPycreus. The third novelty comes under the sectionDiffusi of the genusCyperus proper. The new taxon described under sectionSulcati seems to be remarkable in view of the fact that it possesses a characteristic and a peculiar type of epicarpic surface markings. The vegetative anatomy of these three novelties is also presented here which speaks for their distinctness in this respect.

Comparative studies of vegetative anatomy in the Theaceae of Sri Lanka

Anatomical characters of the mature leaf blade, petiole, young stem and wood were examined in order to substantiate taxonomic boundaries between genera and species of Theaeeae in Sri Lanka. Two species of Temstroemia, one of Adinandra, four of Eurya and two of Gordonia were studied. The presence of sclereids in most organs of the plant was found to be a common character within the family. However, three distinct types of sclereid are reported. Two basic types of stomata, anomocytic and gordoniaceous, are recognized. The origin of phellogen in the young stems is pericyclic in Gordonia and subepidermal in the other three genera. The species within these genera also appear to have several distinctive characters of their own. Important wood characters have been tabulated in order to illustrate the primitive and advanced characters. Gordonia, especially, exhibits anatomical features which are quite different from those of Temstroemia, Adinandra send Eurya.

THE GENUS PLATOMA (GIGARTINALES, RHODOPHYTA) WITH A DESCRIPTION OF P. ABBOTTIANA SP. NOV.1

ABSTRACTPlatoma abbottiana (Gymnophlaeaceae; Gigartinales), a new species of benthic red algae, is described from Isla Mejía and is the second member of this genus reported from the Gulf of California, Mexico. Vegetative anatomy and reproductive details of the carpogonial and auxiliary cell branches of the new species are described and illustrated. Geographical distributions of the seven previously described Platoma species are given. Their distinguishing morphological characteristics are compared to those of the new species. The correct time and place of valid publication of the generic name, Platoma, and some of its binomials are discussed.

Reproductive Structures and Evolution in Ludwigia (Onagraceae). I. Androecium, Placentation, Merism

This article, based on serial sections from 19 species of Ludwigia (supplemented where necessary with preparations from other Onagraceae), begins an effort to outline the evolution of flower, fruit, and seed characters within the genus and to link the outline with what is known of floral evolution elsewhere in the family. New observations include the following: all Ludwigia anthers have a prominent endothecium, and developing anthers of certain advanced species are markedly H-shaped in cross section; pollen of two species matures in isolated packets; ovules of L. leptocarpa, though commonly 1-seriate, can be distally pluriseriate; only rarely does a Ludwigia placenta have a median groove suggesting paired carpel margins.' The deeply intrusive placentas seen in section Myrtocarpus, but lacking in some of the other sections, are probably ancestral, and the old idea that diplostemony and 4+-mery are holds up well when reexamined critically. Few families have been as intensively studied by evolutionary botanists as the Onagraceae. Relationships among many infraspecific variants and among closely connected species groups have been firmly established through cytological work, breeding experiments, and field observations of reproductive events. As one proceeds to more widely separated taxa, however, biosystematic methods become inapplicable; consequently, evolutionary links among the genera of Onagraceae are not yet well understood. Structural comparison remains the bestperhaps the only-way to improve our knowledge of these links. First, structural differences among the taxa must be identified, then the direction of evolutionary change can be inferred by critically weighing the alternatives. The Onagraceae are ideal in several respects for comparative studies of floral structure. For one thing, the family is of manageable size: Raven currently recognizes 17 genera and estimates the number of species to be 600-700. Spirit collections of many of these species are available for anatomical work because of the research efforts of Raven and his collaborators. Another advantage in working with Onagraceae is that the taxa are diverse enough to be challenging, yet undoubtedly of common evolutionary origin. Among the characters that show the Onagraceae to be a natural family are the peculiar viscin threads on onagraceous pollen (Skvarla et al., 1977) and the distinctive 4-nucleate embryo sac (Seshavataram, 1970; Bhatnagar & Johri, 1972:91; Palser, 1975:641). Still another advantage is that the nearest extra-familial affinities of the Onagraceae are known to be among the myrtalean families Combretaceae, Crypteroniaceae, Lythraceae, Melastomataceae, Myrtaceae, Punicaceae, and Sonneratiaceae. Similarities in floral structure within this alliance were recognized by pre-Darwinian taxonomists and are now seen as indicators of shared ancestry, with strong con1 I thank P. Raven and T. P. Ramamoorthy for criticizing the typescript. The National Science Foundation contributed indirectly, via a series of grants to Raven, by supporting the field work of several collectors. Photographs and anatomical preparations are the work of Smithsonian photographer V. Krantz and museum specialist S. Yankowski, respectively. 2 Department of Botany, Smithsonian Institution, Washington, D.C. 20560. ANN. Missoum BOT. GARD. 64: 644-655. 1977. This content downloaded from 157.55.39.138 on Mon, 27 Jun 2016 07:10:40 UTC All use subject to http://about.jstor.org/terms 1977] EYDE-EVOLUTION IN LUDWIGIA 645 firmatory evidence from such diverse sources as embryology (Subramanyam, 1951) and vegetative anatomy (Carlquist, 1975; van Vliet, 1975; van Vliet & Baas, 1975). Ideas on ancestral versus derived in the Onagraceae can be tested by looking into the related families for satisfactory distribution of the putative an-

Vegetative Anatomy of Maihuenia (Cactaceae) with some Theoretical Disucssions of Ontogenetic Changes in Xylem Cell Types

Vegetative Anatomy of Maihuenia (Cactaceae) with some Theoretical Disucssions of Ontogenetic Changes in Xylem Cell Types

Hydatellaceae — a new family of monocotyledoneae

Abstract Studies of embryology and seed anatomy of Centrolepidaceae indicate significant differences between the genera Hydatella and Trithuria on the one hand, and the major part of this family on the other. This agrees with differences in flower morphology, pollen morphology, and vegetative anatomy, and indicates that the family Centrolepidaceae s.l. is a heterogeneous taxon. Therefore, Hydatella and Trithuria are segregated into a newly proposed family, Hydatellaceae. Whereas Centrolepidaceae s.str. seem to be closely related to Restionaceae and Poaceae, the affinities of Hydatellaceae are stilt obscure.

FLORAL ANATOMY IN THE SAXIFRAGACEAE SENSU LATO. IV. BAUEROIDEAE AND CONCLUSIONS

This paper presents a description of the floral anatomy and morphology of Bauera rubioides and a general discussion of how the patterns of variation in floral characters among the subfamilies of the Saxifragaceae sensu lato described in this and previous papers correlate with the patterns of variation in other types of characters (i.e., embryology, biochemistry, etc.). Major conclusions are: (1) The Saxifragoideae, including Ribes, forms a rather homogeneous taxon with regard to floral and other characters. (2) Since the high degree of similarity in floral structure between Itea (Iteoideae) and members of the Saxifragoideae is not correlated with similarities in a number of other characteristics, the affinity between the two probably is not as strong as floral characters suggested. (3) The differences in floral structure between Parnassia (Parnassioideae) and the Saxifragoideae are correlated with differences in other characteristics, and on this basis the taxon should be excluded from the family. (4) Brexia and Ixerba (Brexioideae) are strikingly dissimilar in floral structure and therefore probably do not belong in the same subfamily. Tentatively, Ixerba may find a place in the Escallonioideae, but the relationships of Brexia remain problematical. (5) Bauera (Baueroideae), which has a floral structure quite distinct from that of the Saxifragoideae, shares a number of similarities in embryology, pollen morphology, vegetative anatomy, and biochemistry with the Cunoniaceae and is probably better placed in that family than in the Saxifragaceae. (6) Kirengeshoma palmata (Kirengeshomoideae) should be transferred to the Hydrangeoideae and the whole removed from the Saxifragaceae, since certain floral characters which isolate the group from the Saxifragoideae are correlated with differences in embryology, pollen morphology, leaf and nodal anatomy, and cytology. (7) The Escallonioideae remains a major taxonomic problem because so little information is available on the members of this taxon.

Leaf Anatomy and Systematics of New World Velloziaceae

During a survey of the vegetative anatomy of the Velloziaceae it became quite clear that the taxonomy of the American species seems to be correlated with anatomical characters that are used to distinguish genera in the family, especially in studies by Smith (1962), but that taxonomic treatments of the African species have not been based on a critical evaluation of morphological characters. The first major attempt to remedy this situation was the publication of a revision of the Old World species of Vellozia by Greves (1921). She indicated that the outgrowths on the external ovary walls are sufficiently constant and characteristic to afford a simple classification and that it is not necessary to rely solely on the perianth and stamens as major characters. Earlier, Baker (1898) had treated all the African species under section Xerophyta of Vellozia in the family Amaryllideae, thus following his classification in Bentham & Hooker, 'Genera Plantarum' (i88o). Hutchinson's (1959) treatment essentially follows Baker's classification. In their 'Checklist of the flowering plants and ferns of the Transvaal and Swaziland', Burtt-Davy & Pott-Leendertz (I912: 121), although aware of the undesirability of publishing new combinations in a checklist, transferred to the genus Barbacenia several species described earlier in Vellozia. They made these changes without giving any taxonomic reasons as it was assumed at the time that an account of the family was about to be published in Germany. Such a mass transfer of names was not supported by other botanists (cf. Bullock, 1966). Hutchinson (I959) was likewise aware of the unsatisfactory state of the taxonomy of this family and stressed the need for careful monographic studies. For the American Velloziaceae, Smith's (1962) classification was based on whether the anthers are basifixed (Vellozia) or dorsifixed (Barbacenia and Barbaceniopsis). This classification seems more logical and satisfactory to me since it accords well with the distinctive sclerenchyma distribution in the leaves of this family (Ayensu, I967b & 1968). The present investigation, therefore, is undertaken with the hope that an eventual monographer will take cognizance of the importance of vegetative anatomy in the taxonomy of the Velloziaceae. In his synopsis of the African species of Xerophyta, Baker (1875) claimed that the genus Vellozia was published by Vandelli after Jussieu had named similar plants under Xerophyta. However, it is now known that Vellozia Vandelli (1788) antedates Xerophyta Jussieu (1789) by one year. (See Bullock, 1966, for further information.)

Vegetative Anatomy of Cultivated Grapes--A Review

The anatomy of vegetative structures of cultivated grapevines, as described in selected literature, is presented, with emphasis on development of established vines of <i>Vitis vinifera</i>. Other topics briefly considered are the anatomy of propagules, muscadine grapes, tetraploid vines, phylloxera galls, mineral-deficient vines, and injury of leaves by ozone and 2,4-D. The terms used to describe grapevine morphology and anatomy are defined in a glossary. A growing root shows zones of cell division, cell elongation, and tissue differentiation. Vascular structure is similar in the root and the stem, although the mitotic activity of vascular and cork cambia is more irregular. Root cortex is often invaded by endotrophic mycorrhiza. The stem primary vascular system is composed of leaf, bud, and tendril traces. Procambium and phloem differentiate acropetally, and xylem differentiates in both directions from the nodes. During the first growing season of the stem, a cambium produces secondary xylem and phloem and extends rays. Xylem consists of large scalariform vessels surrounded by thick-walled pitted parenchyma and large masses of living septate fibers. Phloem consists of blocks of living septate fibers alternating with blocks of sieve elements, companion cells, and parenchyma. Ray cells are pitted and thick-walled in the xylem but thin-walled in the phloem. Cells of the stem and root store starch, which is greatly depleted when shoots begin to grow in the spring. Phellogen forms from the living cells of the nonconducting primary phloem in the first year in stems of <i>Euvitis</i> Planch. (in the subepidermal layer in <i>Muscadinia</i> Planch.), and then successively each year in the nonconducting secondary phloem. It cuts off all the tissues lying outside of it, and these are shed with the periderm. In spring, sieve elements formed the previous year are revitalized and function as conduits until new sieve elements are formed from the cambium. Each foliage leaf on a growing shoot has a precocious axillary bud consisting of a single prophyll and a variable number of leaves. This develops into the summer lateral branch. The four vascular traces of this axillary bud diverge from the traces of the subjacent tendril or bud, not from those of the subtending leaf. The bud in the prophyll of the summer lateral develops into the primary bud with 2-3 prophylls, a few leaves, and then several leaves opposed by clusters or tendrils in a generally regular pattern. Formed in the axils of the two basal prophylls of the primary shoot are the secondary and tertiary buds, respectively. These three buds, surrounded by the prophyll of the summer lateral, enter dormancy at the end of the growing season and constitute the compound bud or eye of the mature cane. The next season the primary bud develops into the fruiting shoot. The secondary and tertiary buds may develop into shoots or remain latent for extended periods. A tendril arises as a primordium on the apical meristem opposite that of a leaf. Two of its vascular traces are connected with those of the bud below it, and two with those of the leaf above it. It functions first as a hydathode and later as a twining organ. At each node, five traces to the leaf leave the ring of stem vascular bundles through separate gaps. The traces divide and anastomose to form the complicated network of palmate venation in the leaf, each tooth ending in a hydathode. Blade tissues of a mature leaf, which are differentiated from six layers of meristematic cells, comprise the upper epidermis, one layer of palisade cells, three layers of spongy mesophyll cells, and the lower epidermis with stomates.

The Ecology of Chondrus crispus at Plymouth, Massachusetts. I. Ontogeny, Vegetative Anatomy, Reproduction, and Life Cycle

The Ecology of Chondrus crispus at Plymouth, Massachusetts. I. Ontogeny, Vegetative Anatomy, Reproduction, and Life Cycle