90 FLOWEBLESS PLANTS [BOOK i. 



does not appear to be even solid. It may be seen, also, that the 

 same character gives an indusium to one, a calyptra to the 

 other body, while the application of the term calyptra ceases 

 to be even mechanically correct from being applied to the 

 whole capsule." " In the sporula, so called," he says, " of the 

 more developed Acotyledonous plants, we have organs consist- 

 ing of two envelopes ; the inner of which contains granular 

 matter, has remarkable powers of growth, and, so far as 

 function is concerned, appears to be alone essential. The 

 proper stimulus calls this membrane into growth, and from 

 the apex of its extension cells are developed; from these 

 others again are produced ; and from the centre of the mass 

 thus formed, originates at a certain period the growth of the 

 true axis. Similar phenomena take place in the formation 

 of the seed of Phaenogamous plants, with this difference, that 

 the albumen, unlike, perhaps, the thallus of the Acotyle- 

 donous plant, is not a direct growth from the pollen tube. 

 Such other differences as appear to exist are of minor 

 importance ; they consist in the different nature of the 

 stimulus calling forth the extension of the inner membrane, 

 in the condensation of the growth forming the seed, which 

 may be reasonably inferred to arise from the confined situa- 

 tion in which they occur, and in the cells composing them 

 containing fecula, not green globules, also apparently a con- 

 sequence of the confinement alluded to. The functions of 

 the intermediate growths are in both precisely the same, viz., 

 that of nourishing the young axis until it is sufficiently ma- 

 tured to enable it to maintain an independent existence. 



" The germination of such Acotyledonous plants appears, 

 therefore, to me to be analogous to the development of the 

 seed of Cotyledonous plants, and the perfect state of the 

 lower is analogous to the imperfect state of the higher organi- 

 sation. And to a similar observance of the phases of develop- 

 ment I am tempted to attribute the prevalence of albumen 

 in Monocotyledonous plants, although this is apparently 

 strongly contradicted by the occurrence of the most exalbu- 

 minous and perfect Monocotyledonous embryos in the least 

 organised plants of the class ; and, perhaps, equally so by its 

 prevalence in the monopetalous division of Dicotyledons. 



