362 West. — A Contribittion to the Study of the Mara ttiaceae. 
For this reason, the opportunity of throwing fresh light on several 
points which were in dispute, and of adding to our knowledge of the adult 
sporophyte of the hitherto little-known genus Danaea , was welcomed by 
the present writer, who desires at the outset to express his indebtedness 
to Dr. S. E. Chandler, F.L.S., for his kindness in supplying him with a 
large number of plants of Danaea alata , Sm., and of Danaea nodosa , Sm., 
which were collected by him during a recent visit to the West Indies. 
Material and Methods. 
Apart from the complete series of plants of Danaea alata , Sm., and of 
Danaea nodosa , Sm., already mentioned, material of Angiopteris evecta , 
Hoffm., K aulfussia aescidifolia , Bl., Danaea simplicifolia, Rudge, and of 
several species of Marattia , including a large specimen of Marattia Cooperi , 
Mre., was available for investigation. 
In order to facilitate the elucidation of the complicated arrangement 
of the vascular strands in these ferns, a number of wax models of the 
vascular tissues were built up. The method described by Farmer and Hill 
( 29 , p. 375) was adopted with a few modifications. 1 Although this method 
is very laborious, it has many advantages, inasmuch as every detail of the 
complicated branching and anastomosing of the vascular strands, both in 
the stem and in the leaf-bases of the adult plant, can readily be 
determined. 
For the histological work, a number of stains and reagents, including 
safranin, Kleinenberg’s haematoxylin, eosin, gentian violet, Bismarck 
brown, iodine, phloroglucin + HC 1 , chlor-zinc-iodide, KOH, and con- 
centrated H 2 S 0 4 , were employed. Prolonged staining in a saturated 
alcoholic solution of safranin, followed by rapid staining in Kleinenberg’s 
haematoxylin, was found most satisfactory for demonstrating the presence 
of an endodermis. 
Most of the preparations were mounted in Canada balsam or in 
glycerine jelly, but a few were mounted in euparal ( 46 , p. 247). Euparal 
has a low index of refraction (n = 1-483), and shows up the endodermis, 
when present, even in the regions where its histological characters are 
otherwise difficult to observe. 
1 Owing to their large size and extreme complexity, it was found necessary to strengthen these 
models (1) by introducing into the wax long pieces of copper wire bent to the required shape, and 
(2) by giving them several coats of enamel, which, on drying, formed a rigid covering to the wax 
and effectively prevented its gradual subsidence during hot weather. Electro-plating with copper was 
found impracticable owing to the uneven deposition of the metal, which resulted in the formation of 
numerous centres of weakness and did not add materially to the strength of the models whilst 
greatly increasing their weight. 
