STUDIES IN THE QUERCUS UNDULATA COMPLEX. II. THE CONTRIBUTION OF QUERCUS TURBINELLA

Tucker , J. M. (U. California, Davis), W. P. Cottam , and R. Drobnick . Studies in the Quercus undulata complex. II. The contribution of Quercus turbinella. Amer. Jour. Bot. 48(4): 329–339. Illus. 1961.—Quercus undulata has been interpreted as a hybrid complex involving Q. gambelii and several other species, including Q. turbinella (Tucker, 1961). In the present paper, the total distribution of the hybrids between Q. gambelii and Q. turbinella is given. Lacking direct genetic evidence, proof of hybridity is sought in a demonstration of the morphological intermediacy of these putative hybrids. Population samples of both parental species, other samples containing hybrids, and numerous individual hybrids, are analyzed on the basis of 6 differences between the parental species. The data obtained, presented in the form of pictorialized scatter diagrams, clearly show the general intermediacy of the hybrids. Of the various binomials that have been applied to forms in the Q. undulata complex, Quercus pauciloba Rydb. applies to this hybrid. The appropriate change in status (Quercus × pauciloba Rydb.) is made.     

STUDIES IN THE QUERCUS UNDULATA COMPLEX. V. THE TYPE OF QUERCUS UNDULATA

The original material of Quercus undulata Torr. was collected by Edwin James on Major Long's expedition to the Rockies in 1820. The type locality was stated by Torrey as “sources of the Canadian and the Rocky Mountains.” Evidence is here adduced that the type locality is on Ute Creek, a tributary of the Canadian River, in northeastern New Mexico. The site was found to harbor Q, gambelii, Q. grisea, and numerous intermediate hybrid forms. Certain of the latter match the type of Q. undulata quite closely. The type sheet includes three elements—a branchlet regarded as the type, a twig of Q. grisea, and an isolated acorn of Q. havardii. Torrey's new species was illustrated by a figure which does not closely resemble the type, but which is more similar to Q. havardii. The acorn of Q. havardii on the type sheet must have been collected in the Texas Panhandle or western Oklahoma, where Long's party would have encountered this species. In my opinion, Torrey's figure could have been drawn from a specimen collected there, which, except for the isolated acorn, has since been lost.     

STUDIES IN THE QUERCUS UNDULATA COMPLEX. III. THE CONTRIBUTION OF Q. ARIZONICA

Tucker, J. M. (U. California, Davis.) Studies in the Quercus undulata complex. III. The contribution of Q. arizonica . Amer. Jour. Bot. 50(7): 699–708. Illus. 1903.—Of the 7 oak species involved in the Quercus undulata complex, Q. arizonica contributes the least of all. The latter has hybridized with Q. gambelii at a few widely separated localities (listed in Table 1) in central Arizona, and northern Sonora and Chihuahua, Mexico. The putative hybrids (identifiable as Quercus undulata) occur as isolated individuals with the parental species. The parents, although regionally sympatric, are usually ecologically isolated. They differ in a number of morphological characters, 6 of which were analyzed in detail. The resulting data, presented as pietorialized scatter diagrams, demonstrate that the putative hybrids are intermediate, in general. This is taken as evidence of their hybrid nature. Factors limiting hybridization in oaks are discussed. It is speculated that hybridization between Q. arizonica and Q. gambelii has occurred since the postglacial hypsithermal interval.     

STUDIES IN THE QUERCUS UNDULATA COMPLEX I. A PRELIMINARY STATEMENT

Tucker , John M. (U. California, Davis.) Studies in the Quercus undulata complex. I. A preliminary statement. Amer. Jour. Bot. 48(3): 202–208. Illus. 1961.—The taxonomic history of Quercus undulata, a highly variable, problematic complex of the Southwest, is discussed. Conservatively treated as a single species, it comprises a wide range of forms which at one extreme approach Q. gambelii morphologically, and, at the other, Q. grisea, Q. turbinella, and other species. The postulate was made that Q. undulata had arisen through hybridization between these very different oaks. Field observations and preliminary study of numerous population samples confirm this postulate. (Detailed morphological analyses are in progress.) Seven species have apparently been involved—Q. gambelii (the “common denominator” of the complex) has hybridized in different parts of its range with one or another of the following: Q. arizonica, Q. turbinella, Q. havardii, Q. muehlenbergii, Q. mohriana, and Q. grisea. The latter 6 species are discussed individually, and the extent to which each contributes to the complex, and the area in which this occurs, are indicated.     

STUDIES IN THE EMBRYOLOGY OF COMPOSITAE. IV. THE TRIBE INULEAE

Embryology of Blumea malabarica, B. membranacea, Laggera pterodonta, Anaphalis busna and Vicoa auriculata has been studied. The anther is tetrasporangiate in all the members except in Blumea membranacea where it is bisporangiate. The anther tapetum is of the Periplasmodial type. Both tetrahedral and isobilateral pollen tetrads are found. Mature pollen grains are three-celled with thick spinous exine. The ovary is bicarpellary syncarpous and unilocular with a single basal ovule. In one instance in Blumea malabarica two ovules per ovary with a rudimentary septum separating them was observed. The single hypodermal archesporial cell functions directly as the megaspore mother cell. The embryo sac develops according to the Polygonum type. The synergids in Blumea malabarica are hooked while in other members they are pear shaped. There are three antipodal cells except in Blumea membranacea where they increase up to eight. Endosperm development in Blumea malabarica is of the Nuclear type while in Blumea membranacea and Laggera pterodonta it is of the Cellular type. One or two layers of endosperm persist up to maturity. Embryo development follows the Senecio variation of Asterad type. The embryological information of this tribe along with that of other tribes will be utilized in evaluating the interrelationships of the family Compositae in a later paper.     

STUDIES OF SPERMATOGENESIS IN THE HEPATICAE. IV. ON THE BLEPHAROPLAST OF BLASIA

Spermatogenesis in Blasia pusilla L. was reexamined with electron optics to help evaluate conflicting results of the two earlier light microscope studies of this species. The present micrographic resumé of spermatid transformation confirms Sharp's observation of centrosomes in very young spermatids and agrees with Woodburn's general account of spermatozoid maturation. Further, male gamete development in Blasia is shown to be closely comparable to that of Marchantia and Pellia. It is concluded that Sharp's report of blepharoplast development in Blasia by fragmentation and coalescence was based on anomalous plant material.     

李四光教授在(筵)类研究上的贡献

我国著名地质学家李四光教授自1920年从英国伯明翰大学采矿系学成归国后,终生从事地质科学的研究工作,在微体古生物(筵)类和石炭一二叠纪地层、中国第四纪冰川、地质力学以及石油勘探、地震等领域取得了伟大的成就,并成为中国现代地质科学的主要奠基人之一.     

COMPARATIVE STUDIES OF PYRENOID ULTRASTRUCTURE IN ALGAE OF THE MONOSTROMA COMPLEX123

The pyrenoid structure in 15 species of the Monostroma complex is very diverse us revealed by a study of the morphology of the pyrenoid matrix, associated starch shell, and pattern of intrapyrenoidalthylakoid bands. From these characteristics 8 types of pyrenoid structure were classified. The variation of pyrenoid structure was shown not only among the species studied, but also between the alternation of generations (M. angicava and M. nitidum). In M. fuscum var. splendens, M. groenlandicum, M. undulatum, and M. zostericola pyrenoid structure is the same throughout the life cycle. The pyrenoid matrix of M. zostericola is surrounded by a double membrane that prevents the direct connection of the pyrenoid matrix with chloroplast thylakoids. The pyrenoid also lacks a starch shell. These findings support the establishment of a new genus Kornmannia by Bliding to include M. zostericola. In addition, similarities in pyrenoid ultrastructure suggest an affinity of Capsosiphon fulvescens with M. groenlandicum.     

STUDIES IN THE PHYSIOLOGY OF FOREST TREES. IV. MOISTURE MOVEMENT IN DECAPITATED STEMS

Greenidge , K. N. H. (Dalhousie U., Halifax, Nova Scotia.) Studies in the physiology of forest trees. IV. Moisture movement in decapitated stems. Amer. Jour. Bot. 47(10) : 816–819. Illus. 1960.—The rates and patterns of moisture movement in large, decapitated ring-porous stems have been investigated with the aid of water-soluble dyes injected into the lower boles of standing trees. A few observations have been made also in diffuse-porous trees treated in the same manner. Movement has been found to continue to the very apices of the stubs of oak and elm stems in the complete absence of foliar surfaces. Similar results were obtained in untouched stubs, and in stubs, the sawn surfaces of which were shellacked following decapitation and prior to injection. In oak and elm thus treated, maximum rates of movement approached 1/2 the velocities characteristic of entire stems. In shellacked and unshellacked stubs injected 20–24 hr. after decapitation, rates of movement, although commensurable, were further decreased. The relative distance moved by the stain varied on occasion in ash, and rates of movement dropped markedly in this species following decapitation. Similarly, speeds of travel were much reduced in diffuse-porous species following detopping.     

BIOSYSTEMATIC STUDIES IN THE BOUTELOUA CURTIPENDULA COMPLEX. I. THE ANEUPLOID RHIZOMATOUS B. CURTIPENDULA OF TEXAS

Gould , F. W., and Z. J. Kapadia . (A. & M. College of Texas, College Station.) Biosystematic studies in the Bouteloua curtipendula complex. I. The aneuploid rhizomatous B. curtipendula of Texas. Amer. Jour. Bot. 49(8): 887–891. Illus. 1962.—Widespread throughout central U.S. is a rhizomatous form of B. curtipendula that basically is tetraploid (2n = 40). In the southwest the predominant type is a caespitose aneuploid with a high chromosome number (2n = ca. 80 to 2n = ca. 102). The present study has shown the presence of an extensive series of rhizomatous aneuploids in central Texas, with chromosome numbers ranging from 2n = 41 to 2n = 64. The distribution of these plants is centered about the region of overlap in the ranges of the 2 previously mentioned types. Available evidence indicates that the rhizomatous aneuploids have arisen through hybridization of the caespitose aneuploids and the rhizomatous tetraploids.     

THE CONTRIBUTION OF CEREBRAL ANGIOGRAPHY IN DIAGNOSIS

Angiography is important in the diagnosis of central nervous system disorders. In operable lesions it not only discloses the location of the lesion but also gives valuable information regarding its character and surrounding vascular architecture.The technique of both the pericutaneous and the open methods is described. The advantages of the controlled automatic arteriograph are described as well as pertinent information regarding cerebral circulation time.The choice of contrast media and the advantages and disadvantages of each are described.The three phases of angiography important in diagnosis—the arterial phase, the capillary phase and the venous phase—are discussed.The indications and contraindications are briefly outlined with respect to neoplasms, trauma, hemorrhage, aneurysms and other such operable lesions.The characteristic changes produced by aneurysms, vascular malformations, neoplasms and other space-occupying lesions as related to the circulatory apparatus show variations characterizing the type of lesion encountered.Angiography in traumatic conditions, while limited, is of exceptional value in the diagnosis of obscure lesions, particularly the subdural hematomas.     

STUDIES OF PALEOZOIC FUNGI. IV. WOOD-DECAYING FUNGI IN CALLIXYLON NEWBERRYI FROM THE UPPER DEVONIAN

An extensive fungal infection is present in silicified specimens of Callixylon newberryi (Dawson) Elkins and Wieland from the Upper Devonian of Indiana. Fungi are represented by branched, septate filaments with both terminal and intercalary chlamydospores. Clamp connections were not observed. Tracheids of the secondary xylem, decayed in varying degrees, show erosion troughs, cavities, and extensive lysis of tracheid walls. The pattern of decay is most similar to modern-day white rots, which are typically caused by basidiomycetes, while hyphal features are characteristic of either ascomycetes or basidiomycetes. The presence of wood decay coupled with a septate mycelium suggests the presence of higher fungi in the Devonian and indicates a more diverse Devonian mycoflora than has previously been recognized.