386 DE. A. B. EENDLE — SYSTEMATIC ^--_' 



Campbell shows that in Najas flexilis the oospore divides into an upper cell, whi3h 

 becomes much enlarged to form the primary suspensor-cell, and a lower or embryo-cell, 

 which divides transversely into three cells. From the terminal segment is developed 

 the cotvledori ; from the outer half of the middle segment the growing-point of the stem 

 appears as a lateral outgrowth ; while the bulk of the root is formed from the same 

 segment, only the initial plerome and terminal epidermis being formed from the lowest 

 of the primary embryonic segments. No root-cap was present. The roots in the adult 

 plants of N. flexilis, as of other species, have a root-cap (see fig. 196). 



Affinity. — As already indicated, Najas forms a very distinct and apparently primitive 

 type of Monocotyledon. Its nearest ally is Zannichellia, which resembles it in the 

 axillary staminal structure and the female inflorescence ; the latter is quite comparable, 

 but contains within the spathc several flowers, instead of, as in Najas, a single flower only, 



3. Geographical Distribution. 



The genus is almost world-wide, occurring in all zones except the frigid. It is still 

 unrecorded for certain areas in which it might be expected to occur, such as Tasmania 

 and New Zealand ; Ijut the fact that it has not hitherto been found is scanty proof of its 

 non-existence in any likely locality. The plants are often very small, and, growing 

 completely submerged in water, are likely to be unnoticed, unless a collector is especially 

 looking for them. Moreover the vicinity of w^ater in warm climates often means fever, 

 so that the general collector having no special keenness for Najas wdll naturally shun 

 any likely locality. 



Najas consists of a few widely-distributed, and a number of apparently more or less 

 local species. N. marina (the only member of the subgenus Etmajas), a highly variable 

 species with numerous varieties and forms, occurs over almost the whole area occupied by 

 the genus, but finds its chief development in the north temperate region of the Old 

 World. The type ranges from England, in the south of which it evidently was formerly 

 more widely spread than at present (probably owing to the disappearance of suitable 

 localities), through the central and, in a less degree, the southern portion of the continent 

 of Europe ; fossil fruits have been found in southern Scandinavia. In Asia it occurs in 

 the Himalayan region (Cashmere) and in China and Japan. It will probably be found 

 in Central Asia. It is also known from the north-eastern United States, the West Indies, 

 and north-west Australia. 



One variety only is very widely spread, namely var. angustifolia, w^hich is plentiful in 

 brackish water round the Baltic, and is also known from Assyria, Bourbon, Australia, 

 and the Sandwich Islands. Of the rest, var. ijitermedia occurs in similar localities in the 

 Baltic area and also in North Germany, Switzerland, South Eussia, the Caspian Sea, and 

 Afghanistan. Var. Ehrenbergii occurs in the South-Mediterranean area ; var. mtiricata 

 in Egypt and Ceylon ; var. americana in the eastern and southern United States ; and 

 there is one in each of the following : — Germany, China, Canary Is., Florida, California, 

 Mexico, Venezuela, and Brazil. The subgenus Caulinia has no such widely-distributed 

 species. N. minor ranges from the south of Europe through Syria and Persia to Further 

 India, and I have seen one small specimen from Manchuria. It has a variety (fenuissima) 



