362 



THE MICROSCOI 



Many of the smaller kinds of seeds will reward the 

 microscopist ; use only a low power ; that of Caryo- 

 phyllum (clove-pink), is regularly covered with curiously- 

 jagged divisions; every one of which has a small bright, 

 black hemispherical knob in its middle, represented in 

 fig. 160, A. 



The seeds of the carrot are remarkablv formed, 

 having some resemblance to a star-fish, with its long 

 radiating processes. The seeds of umbelliferous plants 

 have peculiar receptacles for essential oil, in their coats, 

 termed vittce ; various points of interest may be noted 

 as occurring in the testce, envelopes of seeds, such as 

 the fibre-cells of Cohcea, and the stellate cells of the 

 Star-anise. 



All plants are provided with hairs ; and a few, like 

 insects, with hairs of a defensive character. Those in 

 the Urtica dioica, commonly called the Stinging-netile, are 

 elongated ' hairs, developed from the cuticle, usually of a 

 conical figure, and containing an irritating fluid ; in some 

 of them a circulation is visible : when examined under the 

 microscope, with a power of 100 diameters, they present 

 the appearance seen at fig. 188, No. 2. At No. 3, same 

 figure, are represented a few interesting ciliated spores 

 from Confervce. 



The circulation of the fluid contents of vegetable cells 

 may be examined at the same time with the Chlorophyll 

 globules, by selecting for the purpose the transparent 

 water-plants Chara, Nitella, Anacharis, and Vallisneria, 

 or the hairs of Groundsel and Tradescantia. The circula- 

 tion of the sap in plants growing in water is 'termed hj 

 botanists Cyclosis. 



Fossil jylants. — We detect in some of the primordial 

 fossils a noticeable likeness to families familiar to the 

 modern algaiologist. The cord-like plant, Chorda filium, 

 known as ' dead men's ropes,' from its proving fatal at 

 times to the too adventurous swimmer who gets entangled 

 in its thick wreaths, had a Lower Silurian representative, 

 known to the palaeontologist as the Paloeochorda, or 

 ancient chorda, which existed, apparently, in two species, — 

 a larger and a smaller. The still better known Ckondrus 

 crispus, the Irish moss, or Carrageen moss, has, likewise, 



