of the Organs of Pilularia globulifera. 493 



the sporules of Jungermannia complanata exhibit similar lines after they liave 

 been submitted to the action of sulphuric acid. After the protrusion of the 

 germ, however, it does appear to be quite immaterial from what part of the 

 germ the first leaves, root or stem shall arise. 



It is almost superfluous to point out, that these primordial leaves, if the 

 sporules be considered as seeds, have no analogy, except in their use, with 

 cotyledons, because true cotyledons pre-exist in the seed, whereas these are 

 the product of germination. But according to the view of the nature of 

 sporules M'hich I have endeavoured to establish, Pilularia must be considered 

 as nearly allied to monocotyledons in its germination. In cotyledonous plants 

 the first steps of germination (under which term I include the growth of the 

 mature pollen) are protected by a distinct apparatus (the seed-coats) fur- 

 nished for that purpose ; and in monocotyledonous plants a single primordial 

 leaf and root are developed in a sheath, through which they burst in the pro- 

 gress of germination. Now Pilularia differs from this simply in not having 

 the first stages of its germination protected by a separate apparatus, unless, 

 indeed, the conical membranes which form the external cavity (Tab. XXXIV. 

 fig. 6.) at the germinating end of the sporule are to be considered as the most 

 rudimentary state of the female organ ; for, as in monocotyledons, the cellular 

 mass arranges itself into a sheath, which incloses the rudiment of a leaf and 

 root, and the amylaceous (?) particles and grumous fluid, which fill the cavity 

 of the spoinile, fulfil the same oflice as the albumen of monocotyledons. I shall 

 conclude these observations bj' stating that I have not been able to detect 

 any organs which, as in the Mosses, can by any possibility be supposed to 

 perform the oflBce of impregnating the sporules. 



' ' ' Tintinhull, near Ilchester, 

 Feb. 18, 1839. 



EXPLANATION OF THE PLATES. 



Tab. XXXIV. 



Fig. 1. A plant oi Pilularia globulifera, of the natural size. 

 Fig. 2. A mature involucrum, of the natural size, and in a dehiscent state. 



3 t2 



