1,110 research outputs found
Comment on "Typicality for Generalized Microcanonical Ensemble"
The validity of the so-called "typicality" argument for a generalised
microcanonical ensemble proposed recently is examined.Comment: Version to appear in PR
Family I. Chroococcaceae, part 3
The third and final portion of this article
Morphology
The plant -- this term is employed here to indicate a single free cell or a group of cells joined together, usually in a gelatinous matrix. A specimen or single collection may contain many plants of one or few cells mixed with other algae; it may be a single entire globule, cushion, or stratum, or a part of one of these. In the Chroococcaceae and some species of Entophysalis, plants of the same species may be found in the form of strata, cushions, or globules (both microscopic and macroscopic), or as free unattached cells
History of Classification
If botanists prior to 1777 encountered species of coccoid Myxophyceae, they probably referred them to the Linnaean genera Byssus, Tremella, or Ulva. J. Lightfoot in his Flora Scotica (1777) named a conspicuous gelatinous alga from wet places on the Isle of Skye Ulva montana (Anacystis montana of this paper). K Sprengel in Flora Halensis, Mantissa (1807) described green globules floating in a lake near Halle as Coccochloris stagnina During the period of 1790-1850, numerous genera and species were published
Family III: Clastidiaceae
Plants of this family are elongate epiphytic unicells contained in thin gelatinous sheaths. The entire protoplast divides into a uniseriaer chain of rounded cells which often remain united by their membranes after the hydrolyzation of the sheath. The cells, upon separation from each other, elongate and secrete new gelatinous sheaths
Family II. Chamaesiphonaceae
In this family, the plants, originally unicellular, grow eventually into strata or cushions from which filaments of cells penetrate the substratum. The solitary cells are basically attached to the substratum by a sheath of gelatinous material; cell division proceeds, at right angles to the axis of the cell, in an unequal fashion: the apical daughter cell is as a rule much smaller than the basal daughter cell. The upper part of the sheath is burst open, and the small daughter cell passes out of the mother cell sheath or develops in silu within the open sheath
Family I. Chroococcaceae, part 1
Most of the species of Chroococcaceae are capable of developing in various ways: as microscopic or macroscopic globular aquatic plants with homogeneous or lamellose matrices; as aquatic, subaerial, or aetial strata or cushions; or as free single cells where the sheath material has completely hydrolyzed. The cells, their methods of division and regeneration, and the arrangement of the cells in the plant are the chief means of distinguishing genera and species. Division of a cell into two equal daughter-cells is characteristic of the family
Revision of the Coccoid myxophyceae
This study originated as an inquiry, some twenty years ago, into what names should be employed for species of coccoid Myxophyceae found in general collections of algae from various parts of the world. Gradually we accumulated and examined many thousands of specimens. Equally gradually it became apparent to us that only a carefully executed revision of the group, with sufficient attention paid to the morphological variation and life history of each species and with strict adherence to the stern discipline of the science of historical taxonomy, would produce a classification and a nomenclature which would satisfy our desire
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