EREMURUS 
365 
in the year, and often without chlorophyll, the ordinary shoots per- 
forming assimilating work only. The stem is very distinctly jointed, 
and at the nodes are borne whorls of united leaves, closely pressed 
against the stem, and of little or no use in assimilation. The branches 
emerge through the leaf-sheath and thus appear at first sight endo- 
genous in origin (p. 38) ; in reality they are exogenous, but formed 
so much later than the leaves that their points of origin are already 
covered by the leaf-sheath, and so they are compelled to burrow 
through it. Stages in this process may easily be observed. The 
surface of the stem is grooved ; the ridges are occupied by mechanical 
tissue, whilst the green tissue and stomata are at the base of the 
furrows. This is a marked xerophytic structure (p. 166) and is 
repeated very closely in Casuarina. In several sp. the internodes of 
the rhizome are swollen into tubers, which serve for hibernation and 
vegetative propagation. 
The spike is very like the <? fir. of a Conifer, and has as much right 
to the title of flower. It consists of an axis with short internodes, 
bearing a densely packed mass of sporophylls. Each is shield-shaped 
and bears a number of sporangia upon the under side of the head 
(i.e. towards the stem), arranged like the horses of a i merry-go- 
round.’ The spores are of one kind only ; each has, running round 
it, two spiral cuticularised bands of membrane, formed from the outer 
wall and termed elaters . These are hygroscopic, unfolding in damp 
air. In the rolling up again on drying, the elaters of one spore 
become entangled with those of others and cause them to adhere 
together, so that several prothalli may be formed near to one another 
when they germinate upon the soil. This is very necessary, for the 
prothalli are dioecious, though so far as we can tell the spores are all 
alike. The prothallus is fairly large, the male being smaller than 
the female. 
The stems of E . hyemale L. are used for polishing under the name 
of Dutch rushes ; the cell-walls of the mechanical tissues contain much 
silica, as do also those of most sp. 
For further details, see Pteridophyta, and Campbell’s Mosses and 
Ferns. 
Eragrostis Host. Gramineae (x). 100 sp. mostly subtrop. 
Eranthemum Linn. (excl. Pseuderantheinum Radlkf.). Acanthaceae 
(iv. A). 17 sp. trop. As. 
Eranthis Salisb. Ranunculaceae (2). 7 sp. N. temp. E. hyemalis 
Salisb., the winter aconite, is naturalised in Brit. It has a thick 
rhizome or row of tubers, one formed each year. The flrs. appear in 
February, before the leaves, and are solitary and terminal. Each has 
an involucre of three green leaves, a ‘calyx’ of 6 segments, and 
several honey-leaves or petals. 
Eremia D. Don. Ericaceae (iv. 10). 30 sp. Cape Col. 
Eremurus Bieb. Liliaceae (ill). 20 sp. alpine, W. and Cent. As. The 
