Axile Placenta Research Articles

English

Morrison, David A. (John Ray Herbarium, Macleay Building (A 12) , University of Sydney, Sydney, Australia 2006*) 1988. Notes on the fruits of Lechenaultia (Goodeniaceae), with a new species from northern Australia. Telopea 3(2): 159-166. - Characteristics of the fruits and seeds of the 25 species of Lechenaultia are described and 22 of them are illustrated. Lechenaultia ovata, a rare species from the Northern Territory closely allied to L. filifo rm is , is also described. During development of the fruit, the outer walls of the loculi grow inwards and partially fuse with smaller outgrowths from the axile placenta. This results in the seeds being entirely surrounded by tissue derived from the loculus wall. The tissue between each seed then separates horizontally, thus forming an 'article' (after Carolin 1966) containing the seed. These articles then separate from each other, and are the final dispersal unit. It is these articles, with their Abstract Morrison, David A. (John Ray Herbarium, Macleay Building (A 12) , University of Sydney, Sydney, Australia 2006*) 1988. Notes on the fruits of Lechenaultia (Goodeniaceae), with a new species from northern Australia. Telopea 3(2): 159-166. - Characteristics of the fruits and seeds of the 25 species of Lechenaultia are described and 22 of them are illustrated. Lechenaultia ovata, a rare species from the Northern Territory closely allied to L. filiformis, is also described. Since the completion of my recent reVISIOn of Lechenaultia R. Br. (Goodeniaceae) (see Morrison 1987), a new species from the Northern Territory has been brought to my attention by L.A. Craven of the Australian National Herbarium. This species has a distinctive surface sculpturing on the fruits, and this has prompted me to provide detailed notes on the fruits of the other Lechenaultia species. Herbarium specimens of Lechenaultia very rarely possess fruits, and consequently knowledge of fruit shape and structure has been very limited. In particular, Carol in (1966) discusses the fruits of only five species when reviewing the Goodeniaceae, although he does note that the shape of the fruits is frequently a good characteristic for distinguishing species. Mueller (1867) and Gardner & George (1963) depict fruits of two of the species. Fruits The fruit of Lechenaultia is usually described as a capsule contammg a double row of small hard seeds, but it is actually somewhat more complex than this, and it is not homologous with a true capsule. It has been described in detail for L. bilaba by Carolin (1966), and the notes presented here are an extension of this earlier work to cover the rest of the genus. Some of the fruit characteristics that vary between species are listed in Table 1, and the fruits of 22 of the 25 species in the genus are shown in Fig. 1. Gardner & George (1963) depict the fruit of L. subcymasa, which is not included in Fig. 1 due to a lack of material; and material was also not available for L. chlarantha or L. pulvinaris. During development of the fruit, the outer walls of the loculi grow inwards and partially fuse with smaller outgrowths from the axile placenta. This results in the seeds being entirely surrounded by tissue derived from the loculus wall. The tissue between each seed then separates horizontally, thus forming an 'article' (after Carolin 1966) containing the seed. These articles then separate from each other, and are the final dispersal unit. It is these articles, with their

Lourtella, a New Genus of Lythraceae from Peru

A new genus and species of Lythraceae, Lourtella resinosa, is described from Dpto. La Libertad, Peru. It is unique in the family by possessing globose, spiny to spinulose trichomes, discontinuous nectaries, and especially by conspicuous secretory ducts in the stem and pedicel. Floral morphology and anatomy, pollen morphology, and leaf and stem anatomy are detailed. Lourtella is allied to a cluster of four genera, Adenaria, Koehneria, Pehria, and Woodfordia, but the presence of secretory ducts, together with the deviating nature of its globose trichomes and other apomorphies, isolate it within the group. Among recent specimens of Lythraceae sent to the first author for determination was a remarkable, previously unknown member of the family, collected in 1974 from a remote region of northern Peru. The specimen was unquestionably lythraceous as attested to by a large combination of characters: opposite, entire leaves; cymose, bracteolate inflorescences; actinomorphic, campanulate, 4-merous, perigynous flowers with valvate lobes and crinkled, pinnately-veined petals; stamens inserted at mid-level on the inner surface of the floral tube, the anthers dorsifixed with a narrow connective; ovary with reduced septa and fleshy axile placenta; seeds numerous, small, and obpyramidal. Young parts of the plant were coated with copious, resin-like secretions, a feature never before observed in any member of this family. The collection is the basis for description of the new genus and species of Lythraceae, Lourtella resinosa S. A. Graham, P. Baas & H. Tobe. Studies of floral morphology and anatomy, pollen morphology, and leaf and wood anatomy are presented for the collection to confirm the familial position of the plant and to allow detailed comparison with similar, recently published data from other lythraceous genera (Baas 1986; Baas and Zweypfenning 1979; Graham and Lorence 1978; Graham et al. 1986). TAXONOMY Lourtella S. A. Graham, P. Baas & H. Tobe, gen. nov.-TYPE: Lourtella resinosa S. A. Graham, P. Baas & H. Tobe, sp. nov. Fam. Lythraceae. Frutex arborescens ramis oppositis, brevibus, rigide divaricatis; rami juniores folia inflorescentiaque pilis globosis minutis obsiti, medulla caulis orificio secretorio centrali, cortex orificiis secretoriis perforatis. Folia decussata, subcoriacea, oblonga, petiolata. Dichasia 3(4)-flora, axillaria, bracteis bracteolisque persistentibus. Flores 4-meri, homoeostyli, perfecti; appendices 0. Petala 4, alba, tubo aequilonga vel longiora. Stamina 8, ad tubi 1/3_ 1/2 inserta, uniseriata, episepala ceteris vix longiora; antherae tetrasporangiferae, dorso affixae, connectivo parvo. Pollinis grana prolata, 3-colporata; exinio minute verrucato, grano amplitudo parva. Ovarium sessile, globosum, 2-loculare; dissipimenta ovarii fructusque tenerrima; placenta pyriforma vel subglobosa. Nectarium inter basim floris et staminorum locatum, interruptum. Capsula inclusa, tenuissime membranacea, ad apice irregulariter rumpens. Semina circ. 50, obpyramidata, 1 mm longa. Ab Pehria differt orificiis secretoriis caulis pedicellisque, pilis globosis spinulosis, petalis albis, ovario non-stipitatio, nectariis interruptis.

Embryological Studies in Alectra parasitica A. Rich. var. chitrakutensis Rau(Scrophulariaceae)

Summary The anther is tetrasporangiate and at maturity shows a layer each of epidermis, endothecium and tapetum and two or three middle layers. Pollen grains are tricolpate and are shed at the bicelled stage. Gynoecium is bicarpellary and the ovary is bilocular and syncarpous having numerous ovules on the swollen axile placenta. The ovule is anatropous, unitegmic and tenuinucellate. Development of the female gametophyte conforms to the Polygonum type. The endosperm development is ab initio Cellular and the endosperm shows both chalazal and micropylar haustoria; the former is unicelled and binucleate where as the latter consists of two binucleate cells. Development of the embryo follows the Onagra type. Mature seed-coat consists of the epidermal cells which are radially elongated and full of tannin deposition. Pericarp is differentiated into two zones; the outer zone is composed of thin-walled cells while the inner consists of thick-walled lignified cells.

A Revision of Octamyrtus (Myrtaceae)

differs from Rhodomyrtus and other genera of Myrtaceae in the increased number of petals, six, eight or twelve (as against four or five in Rhodomyrtus), which in Octamyrtus are very showy, unequal and strongly imbricate in the bud but enlarge rapidly to up to 6 cm long. Octamyrtus Diels in Engl., Bot. Jahrb. 57: 373 (1922). Shrubs or small trees. Leaves opposite, often large, petiolate, pinnatinerved, villous or tomentose. Flowers large, solitary or in 3-flowered dichasia, axillary or in cauliflorous clusters; bracteoles small and deciduous or leafy and persistent, ovate or lanceolate. Calyx campanulate or turbinate, hypanthium not produced above the ovary, calyx-lobes 4, broad, herbaceous, persistent, unequal. Petals 6, 8 or 12, free, white, pink or red, markedly unequal, strongly imbricate in bud. Stamens numerous in 4--6 series, free, not clustered, incurved near the apex when in bud, finally exserted, filaments filiform, anthers basifixed with parallel cells opening longitudinally. Ovary 4(-7)-locular, with many ovules in 2 series on 4 axile placentas. Style columnar, stigma capitate. Fruit a globose or oblong dry berry. Seeds numerous, compressed-reniform, horizontal in c. 10-30 rows separated by woody to chartaceous, vertical and horizontal false septa, so that the fruit appears to be 8-locular with the seeds in individual compartments. Testa crustaceous, embryo pimentoid (horse-shoe shaped, with a long radicle and short cotyledons). Lectotype species: 0. insignis Diels; McVaugh in Taxon 5: 144 (1956).

Sahniocarpon harrisigen et sp. nov. from the Mohgaonkalan beds of India

The present paper deals with a description of a new petrified fruit from the famous Intertrappean beds of Mohgaonkalan, District Chhindwara, India. The fruit is dicotyledonous pentalocular, septicidal capsule with one elongated triangular seed in each loculus on axile placenta. The seed is anatropous, endospermic showing embryo with axis. The seed coat is characteristically differentiated into three regions. The fruit wall is smooth and parenchymatous with well-developed vascular supply. Affinities are shown with Linaceae though not convincing. Hence this new fruit is named as, Sahniocarpon harrisii gen. et sp. nov.

Contribution to the embryology ofLindernia hyssopioides (L.) Haines

The results of an embryological investigation ofLindernia hyssopioides (L.) Haines [=Ilysanthes hyssopioides] (L.) Benth.] have been presented. The young anther wall consists of three layers of cells in addition to the glandular tapetum. The tapetal cells become binucleate and the nuclei fuse together. The endothecium acquires fibrous thickenings in later stages and the middle layer disorganizes. Quadripartition of microspore mother cells is simultaneous. The pollen grains at shedding are two-celled and tricolpate. The ovules on the massive axile placenta of the superior bicarpellary syncarpous ovary are anatropous, unitegmic and tenuinucellate. The development of the embryo-sac conforms to the Polygonum type. The two synergids are posteriorly vacuolate and have tapering anterior ends. The antipodal cells are ephemeral. The endosperm isab initio cellular. The division of the primary micropylar endosperm chamber is vertical and not transverse. The chalazal haustorium consists of two uninucleate cells. Occasionally it becomes 3-celled. The micropylar haustorium is made up of 4 uninucleate cells. The haustorial cells neither develop lateral extensions nor fuse together during seed development. The development of the embryo is of the Crucifer type. The daughter cell ofd functions as the hypophysis. The seeds are albuminous. The remains of the endothelium and the outer epidermis of the integument constitute the seedcoat. The results obtained have been evaluated in the light of earlier work in the tribe Gratiolae.

The Genus Hoffmannia (Rubiaceae) in Panama

Eleven new species of Hoffmannia (Rubiaceae) and diagnoses of nine previously described species from Panama are presented. A key to the species is included. The tropical genera Hoffmannia Sw., Hamelia Jacq., and Bertiera Aubl. constitute the tribe Hamelieae of the Rubiaceae, with the first two genera restricted to the tropics of the New World. Paul Standley, in his treatment of Hoffmannia in the North American Flora (Rubiales-Rubiaceae (pars) 32(3): 190-208, 1934), recognized 50 species extending from Mexico to Panama, with two species, H. pedunculata Sw. and H. tubiflora Griseb. & Desv., occurring in the West Indies. Airy Shaw (in Willis, A Dictionary of the Flowering Plants and Ferns ed. 7, Cambridge Univ. Press, 1966) notes that there are 100 species of Hoffmannia. Standley, in the North American Flora (loc. cit., pp. 191-193), as well as in the Flora of Costa Rica (Publ. Field Mus. Nat. Hist., Bot. Ser. 18: 1311-1313, 1938) furnishes the only keys to species of Hoffmannia published in relatively recent times; these are accompanied by specific diagnoses. Hoff mannia is a genus of the rain forest with the majority of species occurring at higher altitudes. In Panama, for example, Hoffmannia is generally found at altitudes of 3000 to 6000 ft, although a few species may occur at sea level or at low elevations. Panama seems to represent a good collecting ground for Hoffmannia and is rivaled or surpassed in number of species only by Costa Rica and Guatemala. The fact that eleven new species from Panama are described in this paper suggests the need for an intensification in the collecting of the genus, at least in Central America. Prior to 1959 only about 50 collections from Mexico and Central America were to be found in the herbarium of the Missouri Botanical Garden, with the majority of these from the Province of Chiriqui in Panama. Not a solitary collection from the Panamanian Province of Darien was numbered among these. In the last decade about 50 new Panamanian collections have been added to the herbarium. Particularly noteworthy are the 1968 collections of Dr. James Duke and Mr. Joseph Kirkbride, Jr. from the provinces of Bocas del Toro, Chiriqui, and Darien. Currently, Hoff mannia is known from seven of the nine provinces of the Republic; thus far the genus has not been collected in the provinces of Herrera and Veraguas. The genus Hamelia seems to be the lowland counterpart of Hoffmannia. In Panama Hamelia is rarely seen at high elevations, although the author has seen H. patens Jacq. in the region of Boquete, Prov. Chiriqui, at approximately 5000 ft elevation. Several-characters give evidence of the natural relationship of the two genera: imbricate petals, numerous ovules borne on axile placentas, reticulate ANN. MISSOURI BOT. GARD. 56(2): 269-286, 1969. This content downloaded from 207.46.13.120 on Thu, 15 Sep 2016 05:33:28 UTC All use subject to http://about.jstor.org/terms

DEVELOPMENT OF THE SEED AND FRUIT IN RHINANTHUS MAJOR AND R. SEROTINUS

There are seven sessile, campylotropous, discoid ovules in each loculus of the anteroposteriorly flattened bilocular ovary. They are arranged alternately in two rows in each chamber on the axile placenta which is nodular where the ovules are borne. Nucellus degenerates early except at the chalazal end of the curved embryo sac, and the inntermost layer of the integument functions as endothelium. The aggressive, multinucleate micropylar haustorium grows as a tubular body through the micropylar canal and ramifies in the placenta while the two‐nucleate chalazal haustorium creates a large space by digesting a good deal of the chalazal tissue. Endosperm is differentiated into three regions: the middle storage, the haustorial micropylar, and the chalazal. Thickness of the integument is considerably added to by the endothelium and by its surrounding meristematic zone of the integument. There are two prominent wings on the dorsal and smaller ones on the lateral faces of the cochlidiospermous seed, its ventral face being occupied by a prominent basal body. A heavily cutinized envelope, formed by the endothelium, surrounds the ovoid storage endosperm. Testa of the seed is mainly composed of the thickened epidermis and the endothelium. The micropylar and the chalazal parts of the endosperm become tanniferous and serve to plug the two ends of the seed. Embryo is straight, and it bears two cotyledons and two plumular leaves.

DEVELOPMENT OF THE SEED AND FRUIT IN MELAMPYRUM NEMOROSUM L. AND M. ARVENSE L.

The ovary is bilocular, with four massive axile placentae, each bearing a sessile hemianatropous, unitegmic, and tenuinucellate ovule. The innermost integumentary layer forms endothelium around the micropylar part of the embryo sac. The micropylar canal is surrounded by the micropylar tube, whereas the endothelium is hypodermal in this region. The endothelium and an adjacent meristematic region contribute to the growth of the integument. The endosperm is of the Brunella type described by K. Schnarf in 1929. The chalazal haustorium is a highly aggressive, two-nucleate chamber which becomes inactive and is filled with a haustorial chalazal endosperm. The two multinucleate micropylar haustorial cells give rise to many tubular extensions which pass through the micropylar tube, but only one reaches the placenta. The cells of the storage endosperm are pitted and thickened with hemicellulose. An opaque tanniferous zone of endosperm separates the storage endosperm from the chalazal endosperm. The embryo is small and straight, with two cotyledons and a hypocotyledonary region. The seed coat is feeble, one to three layered. The pericarp is many layered and cuticularized. The two innermost lignified layers form columns at the dorsal line of the two valves of the capsule, where it dehisces. The chalazal part of the developing seed absorbs nourishment directly from the pericarp.

Studies of Floral Morphology in the Epacridaceae

1. The organography and vascular anatomy of the flower have been described for twenty-four species representing twelve genera of the Epacridaceae: in the Epacrideae, Dracophyllum secundum, Epacris impressa, E. longiflora, E. pulchella, Sprengelia incarnata, and S. ponceletia; and in the Styphelieae, Acrotriche aggregata, A. depressa, A. serrulata, Astroloma conostephioides, Brachyloma ericoides, Leucopogon amplexicaulis, L. attenuatus, L. biflorus, L. concurvus, L. melaleucoides, L. microphyllus, L. richei, Lissanthe strigosa, Melichrus procumbens, M. urceolatus, Monotoca scoparia, Styphelia triflora, and Trochocarpa laurina. 2. The flowers of the Epacridaceae are bracteate, tetracyclic, normally pentamerous, sympetalous, hypogynous, and actinomorphic. Anthers are introrse and appendaged only in some species of Leucopogon and in Melichrus. The fruit is either a loculicidal capsule (Epacrideae) or drupaceous (Styphelieae). The ovary is composed basically of five carpels, although the actual number of locules in the ovary ranges from one to ten. The axile placentae bear more than one ovule in the Epacrideae but only one in the Styphelieae. 3. The vascular tissue in the pedicel forms a complete cyclinder which is broken by single traces to the bracts and bracteoles. The cylinder may be continuous or broken at the level of divergence of the sepal traces. In acropetal succession whorls of traces to the following organs arise: sepals; petals; stamens; and dorsal, septal, and ventral regions of the carpels. Various degrees of non-divergence between traces occur, particular between stamen and septal carpel supply. In two species the ventral carpel bundles are found to differentiate and mature basipetally in the central column. 4. Traces to the sepals are occasionally three but more often one; when three, the lateral traces may be independent or arise in common with the adjacent petal traces. The sepal traces may branch immediately on leaving the central cylinder or only in the base of the calyx. The vascular bundles in the sepals are usually associated with either a continuous band or groups of fibers. 5. In the Styphelieae there may be fertile and sterile carpels in the same whorl. The dorsal carpel bundles of the fertile carpels and sometimes of the sterile carpels extend into the style; the laterals and septals fade at the summit of the ovary. 6. The anatropous ovules are unitegmic and tenuinucellate and have a well-developed endothelium. The eight-nucleate megagameotphyte arises from a single archesporial cell. Either the micropylar (6, 33) or chalazal megaspore of a linear tetrad functions; that is, development is of the Polygonum type. A filiform apparatus is frequently present in the synergids. 7. A comparison of the organography and vascular anatomy of the flowers supports the retention of the usual generic divisions in the Epacridaceae and the close affinity of this family with the Ericaceae.