186 Dr. Schleiden on the Development of the 



has taken place — vascular bundles may be detected in the ac- 

 tual integuments; this is, however, very rare indeed. 



Now such a simple envelope [integumentum simplex mihi)* 

 is found under these circumstances : 



1. Without the axis being bent (ovulum atropum cum in- 

 tegumento simplici) in Tax2is at the flowering time, in the CtC' 

 prcssinecCi Juglandecc^ and Ceratophyllece, 



2. Or else the axis suffers the reflexion above described, 

 whereby the envelope becomes adherent to the prolonged 

 axis {raphe) ; (ovulum anatropum cum i?itegume?ito simplici). 

 To this class belong the Abietinecc, Synantherece^ Lioheliacece^ 

 Campanulacea;, Goodenoviea, Lentihularicc^ Scrophularinece^ 

 Oroba7ichece, Gesneriecje, Sesames, Labiatce^ Bignoniacece, Pole- 

 moniacece^ Co?ivolvulacece, SolanecE, Borraginea, Gentianecu, 

 (including the Menyanthece^ which have likewise only one in- 

 tegument ; for the external hard covering, separable from the 

 ripe seed, is nothing more than the epidermis of the integu- 

 ment, whose cells have become much lignified) ; further the 

 Apocyiiecjo^ XJmhelliferce^ JRanunculacecc^ Loasece, &c. 



Lastly, there is a second covering formed, which incloses 

 the point of the axis {integumentum externum et internum mihi), 

 and here also both modifications may occur. 



1. The axis remains straight, as for instance in the Poly^ 

 gonede (fig. 4), Cistinece, Urticece, and a portion of the Arnidece, 



2. Or else the axis becomes bent upon itself, adhering to 

 the external integument (figs. 20 to 23). In the remainder of 

 the family of" the Aroidea^ may be observed all possible states 

 of transition, from an elongated axis, the reflected portion of 

 which, with its integuments, hangs free (as is also the case in 

 Rajffiesia according to R. Brown), to the complete adherence, 

 in which case the unreflected portion of the axis appears as 

 raphe. Further, we must include amongst these all remain- 

 ing monocotyledonous plants. R. Brown has not indeed ex- 

 pressed himself in positive terms on this point with respect to 

 the Orchidece ; they possess, however, decidedly both integu- 

 ments, which are only to be observed in their earliest stages 

 (fig. 5), since the embryo sac having been very early developed 

 has at the time of impregnation almost entirely compressed 

 the micleus, so that one would be induced to consider the very 

 thin integument as the memhrana nuclei, I will content myself 

 with adducing the following among the dicotyledons as exam- 

 ples, to avoid occupying too much room with the mere enu- 



* I feel myself obliged to abandon the usual terms testa and memhrana 

 interna and others which are taken from the ripened seed, and are nowhere 

 applicable, and which would only tend to confuse ideas of things on account 

 of the many errors historically attached to them. 



