262 ME. A. S. HOENE— CONTEIBUTION TO 



alternating with the four -rayed stigma. This fact led to the expectation that either two 

 or four units enter into the composition of the style. He then discovered that the lobes 

 of the canal in C. alba and O. sanguinea are not orientated alike, being situated, in the 

 latter species, opposite stamens instead of petals. In both species, the lobed canal 

 passes into a ribbon-shaped canal, which is homologous with that in C. mas. Clarke's 

 observations led him to the conclusion that the style is composed of the styles of two 

 carpels, that two of the canal lobes are marginal and two sutural, and that the 

 anomalous orientation in 0. sanguinea is due to the imbricate disposition of the 

 congenitally united styles. The writer's observations are in complete accord with tliose 

 made by Clarke. Clarke also found in the case of a flower with a trilocular ovary that 

 the number of canal lobes was increased by two^ — one marginal and one sutural — for 

 each additional loculus. 



The development of the ovary takes place in the manner described by Payer * — the 

 projection is first of all flask-shaped ; later, a basal ridge develops which divides the 

 single cavity into two. The ovules arise from this ridge or septum, one on either side. 

 The ovular mamelon grows downwards. During the downward growth the nucellus 

 differentiates at the tip and is first directed towards the septum ; later, it bends away 

 from the septum, and turns obliquely upwards so that it assumes a tangential position. 



At the same time it is invested by a single integument. 



The development of the ovular mamelon and differentiation of the nucellus were 

 observed in C. alba and sanguinea. The structure of the young nucellus is shown in 

 PI. 29. fig. 67. PI. 29. fig. 65 represents a vertical section through the ovule of 

 Benthamia, in which the nucellus and an early stage in the growth of the single 

 integument are evident. The nucellus resembles a sporangium, since the arche- 

 sporial cells are much alike, but the sporangial appearance is partly due to viewing 

 the nucellus in an oblique plane, for in fig. 66 (Benthamia) and fig. 67 {C. sanguinea) 

 the cells are clearly arranged in rows and, in the latter case, one row [ax) is more 

 noticeable than the rest. A complete series of preparations leading up to the fully- 

 formed embryo-sac has not been obtained. The embryo-sac, however, appears to be 

 formed in the normal manner from one cell of a row of four. A formation of parietal 

 tissue has not been observed. 



Vascular Structure. 



The vascular tissue of the pedicel, in mature flowers of C. sanguinea, separates into 

 an outer series (out ser) of eight and two Inner bundles [in), all of which traverse the 

 wall of the ovary (Text-fig. 5, A). Of the outer series, alternate bundles {st) extend 

 towards the stamens and the remainder (pe) towards the petals B-P. Small inner 

 branches, ovy (B, C), arise from the outer bundles before the latter emerge from the 

 ovary— of which some unite to form the "dorsal" bundles, t? (E, P), present in the 

 style. The bundles st 1 and st 3 (A, B) opposite the inner bundles {in) do not 

 branch. 



♦ J. B. Payer, Traite d'organoge'nie comparee de la fleur (1854-1857), 418. 



