ERIACHNE 
375 
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 c? 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 ‘ 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 
Fe?'ns. 
Eragrostis Host. Gramineae (x). 150 sp. mostly subtrop. 
Eranthemum Linn. (excl. Pseuderanthemum 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 firs, 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. 
Ercilla A. Juss. Phytolaccaceae. 1 sp. Chili, Peru. E. volubilis A. 
Juss., climbing by adhesive discs, endogenously developed just above 
the leaf-axils. 
Erechtites Rafin. Compositae (vm). 15 sp. Am., Austr., N.Z. 
Eremanthus Less. Compositae (1). 20 sp. Brazil. 
Eremia D. Don. Ericaceae (iv. 10). 30 sp. S. Afr. 
Eremophila R. Br. Myoporaceae. 30 sp. Austr. 
Eremostachys Bunge. Labiatae (vi. 4). 40 sp. mid. and W. As. 
Eremurus Bieb. Liliaceae (1 11). 20 sp. Alpine W. and Cent. As. The 
fir. is protogynous ; the petals crumple up before the essential organs 
are ripe. The leaves of E. auranUacits Baker are eaten in Afghan- 
istan. 
Eria Lindl. Orchidaceae (21). 120 sp. trop. As. Epiphytes. 
Eriaclme R. Br. Gramineae (ix). 22 sp. trop. As., Austr. 
