58 Botanical Collections. 



tions of leaves ; and, secondly, by the examination of viviparous species. I need 

 not here remark, that observation has shown us that the leaves of Vasculares have 

 the power of producing leaf-buds from their margin or any point of their surface ; 

 and the instance I have adduced in Grasses of a monstrous Wheat shows that 

 they can produce flower-buds also. I found in Ferns, which are exceedingly sub- 

 ject to become viviparous, that the young plants often grow from the same places 

 as the thecas, or from the margin ; and I was particularly struck with a viviparous 

 Fern, of which a morsel was given me by Dr. Wallich, where the young plants 

 form little clusters of leaves in the place of sori. Upon examining these young 

 plants, I saw that the more perfect, though minute, fronds were preceded by still 

 more minute primordial leaves or scales, the cellular tissue of which had nearly 

 the same arrangement as the cellules of the theca; and I was most especially struclc 

 with the resemblance between the midrib of one of these scales and the annulus of 

 a Polypodium. A view of the thec£e of various annulate Ferns produced a con- 

 viction of the truth of the theory I had formed, which I now submit with much 

 deference to the consideration of the botanical world. It is, however, necessary 

 that I should here add what is only implied in the little work from which 

 the foregoing extract is taken, that this explanation applies only to the gyrate 

 Ferns. 



Reproductive Organs of Mosses, (from the same work, p. 322.)— "The calyptra 

 may be understood to be a convolute leaf; the operculum another; the peristomi- 

 um one or more whorls of minute flat leaves ; and the theca itself to be the ex- 

 cavated distended apex of the stalk, the cellular substance of which separates in 

 the form of sporules." 



It is now time to show upon what evidence and reasoning this hypothesis may 

 be sustained. Every one agrees in describing the calyptra as a membrane aris- 

 ing from between the leaves and the base of the young theca, and as enveloping 

 the latter, but having no organic connection with it : when the stalk of the theca 

 lengthens, no corresponding extension of the parts of the calyptra takes place ; so 

 that it must be either ruptured at its apex (as in Jungermannia,) or at the base ; 

 and in the latter case it would necessarily be carried up upon the tip of the theca, 

 which it originally enveloped. Now, what can be more reasonable than that such 

 an organ, situated as I have described it to be, should be one of the last convo- 

 lute leaves of the axis which the theca terminates, bearing the same relation to 

 the latter as the convolute bractea to the flower of Magnolia, or, to speak more 

 precisely stiU, as the calyptriform bracteag to the flower of Pileanthus ? If the 

 calyptra be anatomically examined, especially in such genera as Tortula and Di- 

 cranum, no difference in its tissue and that of the leaves will be observable ; and 

 that very common tendency to dehisce on one side only as the diameter of the 

 theca increases, which characterizes the dimidiate calyptra, may not unreasonably 

 be understood to be the separation at the line where the margins of the supposed 

 leaf united ; in the mitriform calyptra this separation at a given line does not 

 take place, and the consequence is an irregular laceration of its base. The ana- 

 logy of the calyptra being of this nature, the next inference would naturally be, 

 that the part it contains is analogous to a flower-bud. Upon this supposition, the 

 external series of parts belonging to this supposed bud would be the operculum ; 

 the adhesion of this to the theca, which would answer to the apex of the axis, or 

 to the tube of the calyx of flowering plants, would be analogous to that which ob- 

 tains in Eucalyptus, or perhaps more exactly to that of Eschscholtzia ; but it 

 would remain to determine of how many parts, in a state of cohesion, it was made 

 up. In the paragraph above quoted, it is stated to be one only ; but I confess I 

 have no better reason to offer for this than the absence of any trace of division 

 upon its surface or in the substance of its tissue, and also perhaps the apparent 

 identity of nature between it and the calyptra when both are young, in the Tortula 

 and Dicranum genera already cited. With regard to the peristomium, I would 

 beg attention to the following particulars : — The teeth, as tbey are called, occupy 



