576 TRANSACTIONS OF SECTION K. 
or in a few species immersed, or (among Australian species) are exserted in 
Diospyros laxa. 
The mesophyll is bifacial in the majority of species, but sub-central in 
D. pentamera. 
The palisade cells are usually arranged in a single row, but in the leaves of 
D. microcarpa they are in two rows, and a similar biseriate arrangement has 
been observed in the leaves of D. longipes. 
MONDAY, AUGUST 17. 
The following Papers were read :— 
1. Modern Derivatives of the Matonioid Ferns. 
By Professor F. O. Bownr, Sc.D., F.R.S. 
Cheiropleuria bicuspis (Bl.), Presl, is a fern of the Malayan region, and is 
often associated locally with Dipteris. It is known chiefly from the drawings of 
Sir W. Hooker, and has not been submitted to recent comparative examination. 
On material supplied, through the influence of the Rajah of Sarawak, by 
Mr. Moulton, keeper of the Museum, it has been found that it shows characters 
relating it on the one hand to Gleichenia, Mutonia, and Dipteris, on the other to 
Platycerium. It is, in fact, a synthetic type. ~ 
Its creeping or scandent axis bears alternate leaves, with occasional abaxial 
buds on their bases, as in Lophosoria and Metaxya. The dermal appendages are 
hairs only. The leaf-form varies; the lamina, borne on a long petiole, may be 
one-, two-, or several-cusped; the venation is Matonioid of the type Venatio 
Anaxeti. The axis is protostelic, and the leaf trace originates as a single strand, 
as in Mertensia. It divides in the cortex into two, and undergoes further 
fissions and fusions in its upward course. 
The leaves are dimorphic, the sporophylls being taller and upright, but with 
narrow lamina, marked usually by a strong midrib and enlarged margins. The 
intervening area appears covered by an ‘ acrostichoid’ soral area. 
Detailed examination shows that the sorus is of the ‘ mixed’ type with numer- 
ous paraphyses. The sporangia share with those of Dipteris a segmentation 
different from those of any other known Ferns; viz., by cleavage of the primor- 
dium by alternately inclined walls, to produce two rows of segments. Bipartition 
of the lower segments gives four rows of cells of the stalk, which is also a peculiar 
feature common to Dipteris and Cheiropleuria. The annulus shows slight 
obliquity, and is not completely interrupted at the insertion of the stalk. 
The vascular supply beneath the sorus shows features which link with 
Platycerium. The nerve-endings, which curve downwards to the lower soral 
surface, show enlargement of the distal mass of storage tracheides. Occasionally 
this enlarged receptacular supply may extend from its own definite areola of vena- 
tion, crossing the vein which limits it, into a neighbouring areola. 
This arrangement is a very simple example of what is a regular rule in 
Platycerium. Here, in addition to the conducting reticulum of veins of the 
sporophyll, there is a receptacular vascular system, extended in a lower plane. 
This is composed of branches from the conducting system, which may ramify, 
and extend to considerable length. The definite sori are seated upon these recep- 
tacular veins. These and other characters indicate that there is a real relation 
between Cheiropleuria and Platycerium. ‘The comparative conclusion is this : 
That probably the whole of the Ferns above named sprang from a Gleichenioid 
source. That Jatonia is the most primitive of these genera; Dipteris a more 
advanced type leading to a state with webbed leaves, and a spread of sorus 
over the leaf area. That Cheiropleuria retains the Gleichenioid anatomy, but 
has progressed sorally to an ‘ acrostichoid’ state. That Platycerium is another 
derivative of this phylum, anatomically far advanced: it is also advanced 
sorally, though not -to the ‘mixed’ and ‘ acrostichoid ’ condition seen in Cheiro- 
pieuria. Thus Cheiropleuria and Platycerium are probably modern Matonioid 
types, and it is possible that certain other living genera will also link on to this 
affinity. 
