SCIENTIFIC SUMMARY. 
431 
posed to look upon the abnormality in Tropceolum mojus and the normal 
form in Tropceolum peregrinum as forms representing what might be viewed 
as stages in the evolution of such a species as Tropceolum spedosum from 
some form analagous to Tropceolum majus. In regard to this Dr. Dickson 
adversely criticised the Darwinian hypothesis as, in his opinion, inapplicable 
to the case under consideration. 
Pollen- grains. — Mr. W. S. Bennett, B.Sc., read a paper (Brit. Association, 
Belfast) on the form of pollen-grains in reference to the fertilisation of 
flowers. He stated that although not unfrequently a common form of 
pollen-grains runs through a whole group of plants, yet more often the form 
is found to be adapted to the requirements of the species, and varies even 
within a small circle of affinity. In these plants, which are fertilised by the 
agency of insects, there are three general modes in which the form of the 
grain is adapted for the purpose. We have, firstly — and this is by far the 
most common form — an elliptical grain, with three or more longitudinal 
furrows, as in Ranunculus Jicaria , Acuba jciponica , and Bryonia dioica ; 
secondly, spherical and elliptical, and covered with spines, as in many Com- 
positse, Malvse ; and, thirdly, where they are attached together by threads 
or a viscid excretion, as in Ricardia JEtliiopica. In those plants, on the 
contrary, which are fertilised by the agency of the wind, as most grasses, 
the hazel, and Populus balsamifera, the pollen is uniformly perfectly spherical 
and unfurnished with any furrows, and is generally, moreover, very light and 
dry. The genus Viola supplies two very markedly different, in which the 
grains have the ordinary elliptical three-furrowed form, and where every 
point of the structure of the style and stigma is favourable to fertilisation by 
bees. In all Crucifers hitherto known, the pollen has the most common form. 
In the cowslip and primrose there is a uniform difference in size between 
the pollen belonging to the two forms, that of the short-styled being always 
considerably larger than that of the long-styled form. 
Algce from Jersey. — Dr. Williams read a paper on 11 Specimens of Algae 
from Jersey.” The paper referred to the large number of specimens of 
marine algae’ to be found at Jersey, and to the favourable position of the 
island for the development of algae. Dr. Williams produced a splendid 
collection of algae preserved by a lady residing in Dublin. Dr. Moore said 
that the county Antrim afforded the finest examples of algae perhaps 
known. 
An Abnormality in Chrysanthemum Leucanthemum . — Professor Dickson 
exhibited specimens of an abnormal form of the oxeye daisy ( Chrysanthemum 
lucanthemum), in which the outer florets of the ray (normally ligulate and 
and female) exhibit an irregularly tubular corolla, not very unlike that in 
the neuter florets in certain Centanreas. Structurally these abnormal florets 
are hermaphrodite, but appear always to be functually neuter or sterile. 
(Brit. Association, Belfast.) 
Stems of Tree Ferns. — Dr. Moore read a paper on u The Growth of the 
Stems of Tree Ferns.” Having dealt fully with the matter, he summed up 
his observations, stating, first, that some of the kinds of tree ferns grow with 
greater rapidity and form their stems in a much shorter period than 
is generally supposed to be the case $ secondly, that after they attain a 
certain height the acrogenous buds are formed much closer together, one 
