SECTIONAL TRANSACTIONS.— K. 391 



cotyledons. They have one root and develop into either non-flowering 

 plants with buds — axes of the second order — or, when strong enough, into 

 non-flowering plants with horizontal axillary runners — axes of the second 

 order — bearing triarch adventitious roots at their nodes, and axillary buds — 

 axes of the third order. These give rise to flowering plants with stronger 

 runners and buds. After the flowering of the plant, these buds produce 

 three or four endogenous roots, and rotate until they are at right angles 

 to the axis of the runner. Each bud receives two traces from the con- 

 tinuous xylem of the runner and has a prominent lateral bud in the axil of 

 the lowest leaf, opposite to the region of attachment, which will form next 

 year's runner. Cambium and phloem are abundant in the stem region, but 

 there is little xylem. The roots are pentarch, with no root hairs or xylem 

 plate. On development of the bud into a plant, the roots form xylem plates 

 and triarch laterals. The base of the stem develops continuous xylem, 

 which, higher up, gives place to eight discrete bundles, four cauline and 

 four leafy. 



Prof. J. Doyle and Mr. W. T. Saxton. — Contributions to the life-history 

 of Fitzroya patagonica J. D. Hook. 



Fitzroya, a Chilean genus with one species, is one of the rarer conifers 

 whose development has not previously been worked out. Its general 

 morphological relations with the Callitrinean forms lend particular interest 

 to its study. 



The megaspore mother-cells, formed early iu autumn, are variable in 

 number, but commonly numerous, although only one develops. The 

 pollen tube growth is precocious, deeply invaginating the top of the female 

 gametophyte while the latter is still in the vacuolated stage. The peculiari- 

 ties in the ' endosperm ' development of Cryptomeria as described by Lawson 

 seem here to be repeated. The archegonial complex is rather loose and 

 indefinite and lateral archegonia occur. The early pro-embryo completely 

 fills the archegonium, walls being formed at the end of the second post- 

 fertilisation division. Later embryo stages show considerable variation. 

 In general, Fitzroya presents an interesting link between the strictly 

 Cupressinean type and the Callitrinean type. 



Some abnormalities in the stamens which seem to bear on the morphology 

 of that structure in conifers are illustrated. 



Afternoon. 

 Excursion to the Wolds, Pocklington, etc. 



Wednesday, September 7. 



Miss W. Parke and Dr. M. Knight.— Lj/e cycles of certain members of the 

 Mesogloiacece. 

 The problem of the ' over -wintering ' of algal species described as 

 ' summer annuals ' has been investigated in the case of Mesogloia vermi- 

 culata Le Jol. and Castagnea virescens Thur. Cultivation of spores from 

 unilocular sporangia have resulted in the growth of minute plantlets of 

 ectocarpoid habit bearing plurilocular sporangia. The zoids from the latter 

 may repeat the filamentous phase for some weeks or even months, but 

 eventually, in the early spring, some of the plantlets produce plurilocular 

 sporangia, the liberated zoids from which behave as gametes, fuse in pairs 

 and give rise to a plantlet of disc habit from whose surface finally arise 



