176 ON CUSCUTA GROXOVII. 



The epidermis of dodder varies with its position. On the 

 long internodes between adjacent scales stomata are rare, while 

 over suckers — />., on the side of the stem opposite them — very 

 small stomata are quite abundant. This explains, in a measure, 

 the continuance of life and growth for two weeks or more in 

 branches cut from the parent stem and suspended in the air, 

 though such stems never form coils or suckers. 



Each flower has a short pedicel like the main stem in structure, 

 a thickened receptacle, a five-lobed calyx and corolla with beauti- 

 fully branched fringes lining the latter, and adherent stamens 

 alternating with its lobes ; the ovary has two cells with two ovules 

 in a cell, and there are two knob-like stigmas on short styles. As 

 to the manner of fertilisation of the dodder, whether self or cross 

 fertilised, I have had no opportunity to observe. 



The two-celled ovary is composed of two carpellary leaves, 

 with two cushion-like basal placentae, each bearing two ovules, 

 though at maturity there is often but one. The sections of 

 placentae are deceptive w^hen the ovules are absent, having much 

 the appearance of young ovules. The study of the ovules with 

 reference to the layers in the seed coat gives evidence that in the 

 mature testa there are three. The outer is quite unlike the two 

 below, which are, perhaps, divisions of the same cell layer. They 

 probably arise and cover the nucellus in an early stage, but are 

 not differentiated into the mature form until a late period in the 

 maturity of the ovule. 



A short distance below the apex of each mature embryo, and 

 always on the inside of the curve, as it lies coiled in the seed, is a 

 well-developed scale (Figs. 8 and 9, a). Another scale almost as 

 well developed is usually to be found slightly below the apex of 

 the embryo, but on the outer side of the curve (Figs. 8 and 9, b). 

 These two are separated by quite a portion of the stem in length, 

 and in some cases the second scale is only partially differentiated, 

 and yet a part of the tip, whose tissues, under a high power, are 

 evidently of scales in process of formation. In no case were the 

 scales opposite, or approximating it, as a pair of cotyledons would 

 stand. What may be their relation to the embryo, I do not 

 know, but the apex, with its forming scales, of which this second 

 one is sometimes a part, could well be a plumule. Comparing 



