80 1IIQVEL. — ANNOTAT10 DE OVULO CYCADEARUM. 



amnii et massée cellularis iis "contentge a fecundatione pendere 

 1. c, p. 199, suspicatus sum, cum in ovulis Cycadis revolutœ 

 non fecundatis nec has partes nec ullum embryoblastani e massis 

 illis cellularibus verisimiliter oriundi , vestigium unquam invenis- 

 sem. Idem nunc in viginti ovulis C. circinalis sterilibus confir- 

 matum video, in quibus omnibus albumen reperi bene efforma- 

 tum, apice truncatum et amnio exsiccato calyptratim obtectum, 

 sed absque ullo saccorum (corpusculorum Brownii) vestigio. 



In quibusdam autem casibus , absque pollinis efficacia saccos 

 illos efformari posse, testem nunc habemus certissimum. Cel. 

 Brown enim versioni anglicae dissertationis suae de embryogenesi 

 Coniferarum, postscriptum adjecit, in quo haec leguntur : « With 

 respect to Cycadeœ , whatever opinion may be adopted as to the 

 précise mode of action of the pollen in that family, it is certain 

 that the mère enlargement of the fruit, the consolidation of albu- 

 men, and the complète formation of the corpuscula in its apex are 

 wholly independent of maie influence , as I hâve proved in cases 

 where pollen could not hâve been applied, namely in plants both 

 of Cycas and Zamia (Encephalartos) producing female flowers in 

 England at a time when maie flowers were not known to exist in the 

 country » (Ann. of. nat. histor. May 1844, — separ. impr. p. 7). 



Ex his observationibus concludi potest, massam cellularem quse 

 in saccis illis normaliter invenitur, haud esse tubi pollinici pro- 

 geniem (1). 



(1) Conf. icon. in Observât, meîs tab. 8, fig. 2-5. Z, explicatione tabul. 1. c. 

 ad fig. 3, massa haec cellularis cum utriculis primordialibus Mohl comparatur, 

 haud ex mea sententia, et iis quae (in diss.) de origine embryoblastani ex hac 

 massa cellulari protuli, paene contrarium. Formatur enim cellulis regularibus arcte 

 inter se connexis et corpus sistit plane diversum ab utricula quem Mohlius pri- 

 mordialia vocat. Membrana saccorum propria compagis tenacioris est ita ut té- 

 nacissima e cellulis formata videatur iis similibus , quibus epidermis plantarum 

 constat. 



