TRANSACTIONS OF SECTION K, 925 
leafy or floral endogenous shoots, and branching themselves in an exo- or endo- 
genous manner, The conclusion was drawn that the endo- or exogenous origin of 
an organ or a branch is a phenomenon of an adaptive nature in these plants, and 
to a large extent in others also. The adaptive modifications of the structure, such 
as the gradual reduction through a series of forms of the shoots and leaves, the 
increased multiplication of the shoots by vegetative budding, the reduction of the 
number of flowers per shoot and the change to anemophily, the increased dorsi- 
ventrality, and other characters were shown to be rather correlated with the rise 
and fall of the water than with the velocity of the stream. In conclusion some 
of the more general questions of morphology were discussed in the light of the 
observations made on these plants. 
4. Note on the Anabena-containing Roots of some Cycads. 
By W. G. FREEMAN. 
Attention was drawn to the manner in which the anabiena-containing roots 
were borne on various members of this group, growing in very poor soil, in an open 
garden border in the Royal Botanic Garden at Peradeniya, in Ceylon. 
In the majority a dense coralloid mass of specialised fleshy roots was found 
immediately encircling the main stem. 
In others—e.g. Nacrozamia Peroffskiana—normal-looking lateral roots ran 
horizontally beneath the ground, giving off the special algal-containing roots at 
intervals. These primary lateral roots were themselves sometimes apogeotropic 
for a period, resuming a normal habit of growing downwards again after having 
borne the anabsena-containing masses. 
5. A Mixed Infection in Abutilon Roots. By E. J. Burter, WB. 
The roots of seedlings of Abutilon hybrids (Darwinii x ?) in the plant- 
houses of Queen's College, Cork, presented tuberoid enlargements, due to at least 
two parasites, a Nematode and an Ascomycete. 
(1) The Nematode is a Heterodera, apparently identical with ZH. radicicola. 
It is found also in abundance on the roots of Solanum Capsicastrum. All stages 
of the life-history were worked out. If the female penetrates the central connec- 
tive tissue of the stele, it daes not emerge. The worm will hatch and go through 
a part of its development in water containing decomposing roots of Adbutilon. 
Experiments as to whether it can complete its cycle in liquid are in progress, 
(2) The Ascomycete is a new Thielavia, which I propose to name 7. Hartogit, 
differing from 7. basicola, Zopf, with more abundant gonidia (up to a hundred) in 
each pseudo-sporange, and dark green chlamydospores. Only young perithecia 
were observed. This is a dangerous parasite under favourable conditions of moisture 
and temperature. j 
(3) A fungus coexisting with (1) and (2), whose unseptate hyphz and ‘ cellulose 
wall and reproductive bodies recall Peronosporez, has been partially studied ; it 
appears to be relatively harmless. emg 
The research was commenced, at Professor Hartog’s suggestion, in the"Bio- 
logical Institute of Queen's College, Cork, and continued under Professor; Van 
Tieghem’s direction at the Muséum d’Histoire Naturelle, Paris, 
6. Remarks on Fern Sporangia and Spores. 
By Professor F. O. Bower, 7.2.8. 
