528 Bower—Studies in the Phytogeny of the Filicates. 
state of the sporophyll in Platycerium , with its double vascular system in 
the fertile region. 
7. Its slightly oblique annulus, four-rowed sporangial stalk, and 
alternate segmentation of the primordium, form a peculiar link with 
Dipteris , which is shared also by Metaxya. 
8. The mixed characters which this Fern shows are one of the clearest 
examples of non-parallelism of progression in the several criteria used for 
comparison among Ferns. 
9. The outcome of its comparative examination is to strengthen the 
relation of Dipteris and Matonia to some Gleicheniacious source. 
10. It shows that probably Platycerium is also a Dipterid derivative, 
specialized for an epiphytic habit. 
11. Probably other Dipterid derivatives will also be found on detailed 
study, in such forms as Leptochilus , Neocheiropteris , and some others. 
12. Thus the representation of Matonioid-Dipterid derivatives among 
living Ferns appears to be more extensive than had been hitherto 
appreciated. 
EXPLANATION OF FIGURES IN PLATES XXIV AND XXV. 
Illustrating Professor Bower’s Paper on Cheiropleuria bicuspis (Bl.) Presl, and allied genera. 
PLATE XXIV. 
Fig. 1. Specimens of Cheiropleuria bicuspis (Bl.) Presl, from the Lingga Mountains, Borneo, 
showing the general habit, the one-cusped and two-cusped sterile leaves, and one narrow fertile 
leaf. Reduced to 
Fig. 2 has been placed at the top of Plate XXV. 
Fig. 3. Two sterile leaves of the bi-cusped type, as shown in Hooker’s Figure. Jourm of 
Botany, 1846 ; also one fertile leaf. Reduced to 
Figs. 4, 5. Specimens with irregularly furcate leaves. Reduced to 
Fig. 6. A leaf of Platycerium Hillii , Moore, for comparison with Figs. 4 and 5. Reduced to^. 
Fig. 7. Instead of this there has been substituted Text-fig. 1, which see. 
Fig. 8. Transverse section of the protostele of Gleichenia linearis , Clarke ( = G. dichotoma , Hk.), 
from a section by Professor G Wynne-Vaughan. x 30. 
Fig. 9. Transverse section of the protostele of Gleichenia Jlabellata , R. Br., from a section by 
Professor Gwynne-Vaughan, taken at a point where a leaf-trace is being given off. ( x 30). 
Fig. 10. Transverse section of a protostele of Cheiropleuria, showing a leaf-trace being given 
off from it. x 45. 
Fig. 11. A similar section of Cheiropleuria , showing the leaf-trace completely separated. It has 
two internal protoxylem-groups, with the metaxylem surrounding them completely—a condition 
which holds only for a short distance, x 30. 
Fig. 12. Transverse section of a young stele of Cheiropleuria , showing the absence of protoxylems, 
except in the young leaf-trace, while metaxylem tracheides are developing simultaneously, scattered 
through the whole area, x 45. 
Figs. 13, 14. Transverse sections showing the leaf-trace on its outward course, and beginning to 
bifurcate, x 30. 
Fig- 15* Transverse section of the stem of a seedling of Dipteris conjtigata , Reinw, showing 
a protostelic state, x 45. 
