摘要:

Detailed descriptions, supplemented by line drawings, of holotype collections of 13 species of wood-rotting fungi described from North America by Burt are presented. Additional specimens are cited, providing many new geographic records and substratum relationships for North America. Hyphal systems are discussed andHypochnus canadensisBurt (nowTomentella bombycina(Karst.) Erikss.) is reported as having a dimitic hyphal system. One new combination is proposed,Tomentella epigaea(Burt) Larsen (basionym,Hypochnus epigaeaBurt).

ISSN:0008-4026    

DOI:10.1139/b65-159

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

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 theBrunellatype 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.

ISSN:0008-4026    

DOI:10.1139/b65-160

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

The blue-green algaAnacystis nidulanswas treated with different concentrations of colchicine, sulfanilamide, hydroxylamine, and diethyl sulfate. Its growth was inhibited by relatively low concentrations of hydroxylamine and diethyl sulfate but not by those of colchicine. Colchicine stimulated the algal growth at a concentration of 1000 mg/l and inhibited it at a concentration of 5000 mg/l.Strains of the alga that are resistant to high concentrations of sulfanilamide were produced by subculturing it in increasing concentrations of the drug. These were found to be fully cross-resistant to the same concentrations of sulfaguanidine but not to sulfathiazole. Repeated subculture of the alga in an hydroxylamine medium failed to increase materially its resistance to hydroxylamine.Treatment ofAnacystis nidulanswith the mutagen diethyl sulfate failed to induce any streptomycin-resistant mutants.

ISSN:0008-4026    

DOI:10.1139/b65-161

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

Vegetative proliferation was observed on plants ofAgropyron spicatum(Pursh) S. & S. (including var.inermeHeller) in a growth room, plant nursery, and two field sites. Plantlets were formed both in the spikelets, usually in the terminal florets, and on vegetative culms. Only certain plants from thePseudotsuga menziesii – Agropyron spicatumassociation exhibited this phenomenon. The phenomenon is probably physiological, induced by environmental changes, but genetic predisposition must also be present.

ISSN:0008-4026    

DOI:10.1139/b65-162

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

The anther is tetralocular and its wall consists of four layers: epidermis, endothecium, a middle layer, and the uninucleate tapetum. The endothecial cells develop characteristic fibrous thickenings. Microspore mother cells divide meiotically to form four nuclei. One of them grows in size and becomes the functional nucleus of the pollen grain while the three non-functional ones are pushed to the periphery. A cleavage furrow accompanied by a cell plate separates them from the functional nucleus. Similar walls, though less prominent, separate the non-functional nuclei from each other. The walls are comparatively distinct inCyperus rotundusandKyllinga melanospora.The ovule is anatropous, bitegmic, and crassinucellate. The inner integument forms the micropyle. An outgrowth from the funiculus gives rise to an obturator. The hypodermal archesporial cell divides to form a two-layered parietal tissue and a sporogenous cell. Embryo sac is of thePolygonumtype. Double fertilization takes place.The embryogeny conforms to theJuncusvariation of the onagrad type inCyperus rotundusandKyllinga melanosporaand to the asterad type inScirpus mucrinatus.The integuments each are two-layered. The inner becomes three- to four-layered at the micropylar end. Both of them ultimately fuse to form a thin testa. The thick pericarp also functions as testa.

ISSN:0008-4026    

DOI:10.1139/b65-163

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

The origin of the pectic layer of the cell wall ofScenedesmus quadricaudacan be related to the activity of the nuclear envelope. During the four-nucleate stage, dense vesicles are formed by budding off from the outer nuclear membrane. These vesicles then migrate toward the plasma membrane and their contents are released from the cytoplasm by the process of reverse pinocytosis. From the released matrix the props and the net are organized; they become the easily recognized basic structure of the pectic layer of the cell wall.

ISSN:0008-4026    

DOI:10.1139/b65-164

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

Cone count records for a 28-year period on 80 Douglas fir, 14 grand fir, and 9 western white pine were statistically analyzed with the annual diameter increment to evaluate the relationship between cone and wood production. The width of annual rings was depressed only during the years of cone production, suggesting that carbohydrates used in cone development were supplied from current photosynthesis rather than from stored reserve. The initiation of reproductive buds did not appear to be dependent on the level of carbohydrates in a tree and the role of carbohydrates was probably only that of nutrition during cone development. Maturing cones did not exhibit any inhibitory effect on initiation of new flowering buds. Different species may require a different combination of climatic factors for initiation of flowering buds.

ISSN:0008-4026    

DOI:10.1139/b65-165

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

In studies ofCronartium quercuum(Berk.) Miyabe ex Shirai, temperature and moisture conditions necessary for spore production, spore germination, and oak and pine infection were determined. Seasonal development studies then revealed that a series of favorable events was necessary for an inoculum "buildup" to occur on oak. Initial infection of oak by aeciospores resulted from at least 10 hours of saturated air accompanied by free water with the temperature between 8° and 28 °C. Late spring frosts and dry weather during aeciospore dissemination limited the spread. Secondary spread by urediospores was limited by dry weather and the decreasing susceptibility of oak leaves with age. The susceptible foliage produced by sprouts from recently cut oak stumps tended to prolong uredial spread. Infection of pine was only possible when viable teliospores were present on oak. During the years 1955–1958 in central Wisconsin they were present from the first week in June until the first of July if secondary spread by urediospores did not occur, or for about 2 weeks longer if secondary spread did take place. A period of at least 13 hours of 100% relative humidity following a measurable rainfall was necessary for production and germination of basidiospores. These conditions occurred infrequently and in some years not at all in central Wisconsin.

ISSN:0008-4026    

DOI:10.1139/b65-166

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

Morphological and anatomical studies of two species ofLepisorus(J. Smith) Ching,L. excavatus(Bory) Ching andL. thunbergianus(Kaulf) Ching, are described in detail for the first time. Both the plants are epiphytic with small, creeping rhizomes, bearing branched roots and two rows of simple, lanceolate, glabrous, short-petioled leaves. In both cases the roots are diarch, the rhizomes are dictyostelic, and the petioles have many vascular bundles. Leaves have a T-shaped xylem. Large, rounded exindusiate sori are arranged on either side, close to the midrib, in two rows. Sporangia are leptosporangiate and protected by peltate paraphyses. Monolete, bilateral spores with a two-layered granulate exine are present.

ISSN:0008-4026    

DOI:10.1139/b65-167

出版商:NRC Research Press    

年代:1965

数据来源: NRC

ISSN:0008-4026    

DOI:10.1139/b65-168

出版商:NRC Research Press    

年代:1965

数据来源: NRC