20 J. SATJNDEES NOTES ON THE CHAKACE^. 



have received but scant attention from Britisli botanists. This 

 cannot have been on account of their obscurity, for they often 

 occur in large masses. It may have been that they were regarded 

 as ill-adapted to make presentable specimens for the herbarium ; 

 but this is now proved to be erroneous, chiefly through the skill 

 and industry of Messrs. H. and J. Groves, who have expressed the 

 opinion that "no plants better repay a little care" (' Journ. 

 Botany,' 1880). These gentlemen have added largely to our 

 knowledge of this group, especially with regard to the critical 

 determination of species ; they have also enlisted the sympathies 

 of observers in various parts of the British Isles, through whose 

 efPorts many interesting points have been brought to light both as 

 to the distribution and as to the existence of species previously 

 unrecorded for Britain. Hitherto the South Midlands had been 

 a comparatively unexplored region in this respect. The list 

 appended to this paper represents fairly the forms now known 

 to exist in this district. 



LlFE-HlSTORT. 



The reproductive organs are known as globules (cf ) and nucules 

 (?). The former are spherical and are composed of eight flat 

 cells. These are shield-shaped, and from the inner side of each of 

 them there projects a cylindrical cell, which bears at its apex 

 a number of delicate filaments composed of a row of disk-shaped 

 cells, each of which contains an antherozoid. These are slender 

 spiral threads thickened at one end and terminating at the other in 

 two delicate cilia. The globules when ripe break up into the eight 

 parts of which they are composed, and the filaments rupture and 

 allow the antherozoids to escape. This usually happens in the 

 morning, and the antherozoids have the power of locomotion for 

 several hours. As a single globule contains from 20,000 to 40,000 

 of these organs, the fertilization of the nucules is usually efiPected — 

 at least, if one may judge by the abundance of them which may be 

 found on the fertile branches. Parthenogenesis also occurs. 



The fruit-bearing organs consist externally of fine spiral cells, 

 the apices of which form the " coronula " of the nucule. When 

 fully ripe the antherozoids find their way through minute clefts 

 between the coronal cells, and thus reach the oosphere, which 

 they fertilize. A change takes place in the colour of the ripening 

 fruit, which eventually falls off and awaits development when 

 conditions are favourable. The fruits upon germination give rise 

 to a pro-embryo, which attains only small dimensions, and consists 

 of a single row of cells with limited apical growth. From the 

 pro-embryo the sexual-bearing plant is produced, which is usually 

 developed at nearly right angles to the former {vide Sach's 

 ' Text-book of Botany,' ed. 2, p. 293). In the growth of the 

 plant the internodes are formed of a single elongated cell which 

 often becomes spiral. 



In the genus Chara the stem and branchlets are covered with 

 cortical cells. The number of these parallel cortical cells bearing 



