108 



CHAPULTEPEC 



CHARA 



as, for example, those of York, Southwell, and 

 Wells. The original stained-glass windows remain 

 at York, and are of exquisite beauty. On the walls 

 of that of Westminster the original painting has 

 been discovered. Chapter-houses are of various 

 forms : those at York and Westminster are 

 octagonal; those at Oxford, Exeter, Canterbury, 



Chapter-house, York. 



Gloucester, &c. are parallelograms ; Lichfield is an 

 oblong octagon ; Lincoln, a decagon ; and Worces- 

 ter a circle. In France the chapter-house is gener- 

 ally square. They are always contiguous to the 

 church, and are not generally placed to the west 

 of the transepts. They sometimes open into the 

 church, or are entered by a passage, but are more 

 frequently in connection with the cloisters. In 

 some instances there are arches or windows between 

 the chapter-house and the cloisters to enable those 

 standing in the latter to hear what goes on in the 

 chapter- house. A stone seat on a raised step gener- 

 ally runs round the apartment. Chapter-houses 

 were often used as -places of sepulture, and have 

 sometimes crypts under them, as at Wells and 

 Westminster. 



Chaimrtepec, a rock 2 miles SW. of the city 

 of Mexico, rising to a height of 150 feet, and 

 crowned by a castle, which was erected by the 

 Spanish viceroy in 1785 on the site of the palace of 

 Montezuma. 



Char, a fish. See CHAER. 



4'liara. The Characeae or Stoneworts are a 

 small group of common aquatic plants found grow- 

 ing in large tufts, or even covering large expanses 

 on the bottoms of fresh-water ponds and shallow 

 lakes, brackish or even salt-water lagoons, &c. , and 

 of which the systematic position has undergone the 

 most extraordinary and instructive vicissitudes. 

 The early botanists, with K. Bauhin, had no hesita- 

 tion in describing them as horsetails ( Equisetum ). 

 In 1719 Vaillant proposed for them a separate genus 

 (Chara), while Linnaeus, although at first disposed 

 to regard them as Algae, as their habitat suggests, 

 decided that the small red male reproductive body 

 must be a stamen, and the larger green female one 

 a pistil, and accordingly placed them as flowering 

 plants among the Moncecia Monandria. His pupils 



Fig. 1. 

 Shoot of Chara. 



at most ventured to remove these to the Monandria 

 Monogynia, while De Jussieu regarded them as a 

 genus of Naiadaceas (q.v.), an order of monocoty- 

 ledonous aquatics with much reduced flowers. In 

 similar opinions he was followed by De Candolle 

 and other eminent systematists : and it was not until 

 1851 that a careful re-examination of their structure 

 and mode of reproduction by Thuret finally dis- 

 proved the phanerogamous view, and established 

 their cryptogamic nature. Since that time the 

 group has attracted great attention, and is now on 

 grounds of peculiar instructiveness, both morpho- 

 logical and physiological, one of the 

 classical forms usually presented to 

 the beginner, not only in crypto- 

 gamic botany, but general biology. 

 Commencing with the vegeta- 

 tive system, we find this apparently 

 consisting of a stem with regular 

 whorls of leaves arising at detinite 

 points (nodes) of the stem. The 

 mternodes, or distances between 

 these, are at first considerable ; 

 but as we approach the apex these 

 are shorter and shorter, and at 

 length we lose sight of them in 

 the crowded terminal bud. The 

 resemblance to a young shoot of 

 Equisetum is so far satisfactory, 

 and the mineral incrustation (in 

 some species so abundant as to 

 lead to the substitution of the 

 plant for scouring metal ) appears 

 to confirm this. The incrustation, 

 however, is calcareous, not silice- 

 ous. Even under microscopic ex- 

 amination we may at first sympathise with the 

 old observers, and seem to see in the stem a 

 multicellular structure, even a cortex ; nay, to 

 see under our very eyes the actual circulation of 

 the sap. More careful scrutiny, however, enables 

 us to repeat the work of later and more accurate 

 observers. We see that this movement is not the 

 circulation of the sap in a stem, but a streaming of 

 the protoplasm within what is simply a single 

 enormous cell stretching from one node to the 

 next ( see CELL ). The apparent cortex is a single 

 layer of cells 

 covering this 

 internodal cell ; 

 and the whole 

 vegetative 

 structure is un- 

 ravelled when 

 we roughly dis- 

 sect out the 

 terminal bud, 

 harden, stain 

 and imbed this 

 in paraffin, and 

 thus cut a fine 

 longitudinal 

 section ( fig. 2 ). 

 An apical cell 

 is seen which 

 continually 

 segments oft' a 

 lower one ; this 

 divides ( still 

 transversely to the axis ) into two new ones ; and 

 the lower of these henceforth steadily lengthens 

 as the internodal cell, while the upper undergoes 

 repeated division, until a plate of nodal cells 

 is formed. In the simpler family (Nitella) the 

 internode thus consists of a single naked cell : 

 in the higher (Chara), this is inclosed by the 

 so-called cortex, a layer of smaller cells proceed- 

 ing from those of the upper and lower nodes ; 



Fig. 2. Longitudinal Section of 

 the apical bud of Chara. 



