158 Johnson. — On Arceuthobium Oxycedri. 
distributed. The general result of the investigation tends to 
show that in the possibility of the formation of two embryos 
and in habit the affinity of Arceuthobium to Viscum album 
is closer than was generally supposed 1 . 
7 . Summary. 
There is found in the ovary at the time of pollination a 
basally attached freely projecting conical ovarian papilla, 
containing two apico-lateral imbedded embryo-sacs in which 
the contents are arranged as in a normal angiosperm. The 
embryo-sacs arise in each case from a single hypodermal 
archesporial cell. The morphological value of the contents of 
the ovary is the same as in Loranthus sphaerocarpus as 
described by Treub, the papilla consisting of the modified 
apex of the floral axis and constituting a placenta bearing two 
buried ovules reduced to embryo-sacs. At no time does the 
papilla fuse with the wall of the ovary, its apical region 
becomes a pseud-calyptra to the solitary embryo which is 
straight, and has an exserted radicle without a root-cap. The 
dehiscence of the fruit is due in the end to the rupture of a 
basal horizontal meristematic zone. The seed is covered by 
the endocarp, the most external layer of which consists of 
viscid cells, which are severed at their peripheral (distal) ends 
at ejection of the seed. The sessile anthers in the expanding 
male flower, with a fibrous epidermis and no vascular bundle, 
are in the young flower seen to be distinct stamens. The 
carpels like the stamens are evascular, and are opposite, not at 
right angles, to the perianth-segments. The only points to be 
added to the complete description of the vegetative organs by 
Solms-Laubach are the absence (in my material) of any 
adventitious purely vegetative shoots, the presence of a con- 
stant connection of the xylem-vessels of the parasite with 
the tracheides of the host, and the cleavage of the radial 
wall of the tracheide of the host by the finest parasite- 
haustoria. 
1 Jost’s paper, Zur Kenntniss der Bluthenentwicklung der Mistel, in Botanische 
Zeitung, 1888, No. 24, has appeared since this paper was in the press. 
