4^ 



MORPHOLOGY OF ANGIOSPERMS 



subulata, and certain of the Araceae by Campbell Z1 - 4 '- 4;> ; and 

 there is no doubt that numerous other eases await discovery. 

 It should he remembered also that in many cases of epigyny the 



ovules are probably to be regard- 

 ed as cauline, and if these be 

 added to the cases already indi- 

 cated, it becomes evident that 

 cauline ovules are exceedingly 

 common and occur in all grades 

 of Angiosperms. 



In this connection the curious 

 condition in Loranthaceae and 

 Balanophoraceae may be consid- 

 ered, a condition that may have 

 some connection with their pecul- 

 iar habits. In 1858 Hofmeis- 

 ter *' 5 studied various species and 

 outlined the prominent features 

 of these groups, describing and 



Pig. 17. — Balanophora qlobosa. .J, nu- ■ -,, ,• -i ,i 



,, ... r ., ,, - , illustrating several stages m the 



cellus with mother-cell of embryo- a o 



sac (shaded) ; the epidermal ceils development of the arehegonium- 



like megasporangium, and also of 

 the endosperm and embryo of 

 Balanophoraceae (Fig. 10), and 

 also the puzzling " mamelon " in 

 Loranthaceae. Subsequent inves- 

 tigators have in the main con- 

 firmed and extended this work, the most important modifi- 

 cation being in the interpretation of the embryo ; and even 

 here Hofmeister's figures are nearly identical with those 

 of the most recent papers (cf. Fig. 16 with Fig. 107). In 

 1882 Treub 18 described the development of the pistil of 

 Loranthus sphaerocarpus (Fig. 19). A structure ("mame- 

 lon") arises from the bottom of each of the three or four 

 sporangial chambers and grows until it completely fills it, 

 and in this structure hypodermal archesporia appear and 

 develop megaspores in the usual way. It is a fair question 

 whether the " mamelon " is a growth of the axis, whose ovules, 

 represented by separate archesporia, are mechanically hindered 

 from any superficial development; or whether it is an ovule 



above the mother-cell give rise to the 

 outgrowth resembling the neck of an 

 archegonium. U, later stage in which 

 the mother-cell has divided into two 

 cells, both of which " very often de- 

 velop into embryo-sacs"; x 166. — 

 After Lotst. 18 



