MR. Т. Н. CORRY ON ASCLEPIAS CORNUTI. 175 
situation, it ought always to be regarded as stigma, and not style; and such, indeed, 
Payer (loc. cit.) believed it to be. More recent observers, however, declare that the disk 
of Аросупасезе is stylar, while they still regard that of the Asclepiads as stigmatic. И 
we confine and restrict the term stigma to * that part of the style which is destined for 
the reception of the pollen," and is in consequence specially modified for this function, 
many of the difficulties would vanish completely. The Asclepiadez form only one among 
many cases where the employment of this identical term “ stigma,” in a wider, but at the 
same time in an erroneous sense, has led to much confusion. Adopting then the defini- 
tion which has been advanced, it is evident that the disk of Apocynacez and of Ascle- 
piads is of the same nature, viz. stylar. 
The receptive surface of Asclepias is not confined, as Eichler* thinks, to five linear 
lines or bands, but covers the entire inferior surface, though it is only exposed to the 
exterior at five points, because in these situations it can alone be effective. The number, 
five, is, however, determined by the surrounding parts of the flower. 
I have used Haworth's term, style-table, to indicate this table-shaped mass formed by 
the united style-apices, inasmuch as it bears the stigma, or specially receptive tissue, on 
its lower surface in Asclepias, and also because the term is a convenient one to employ in 
description. 
Owing to the fact that the two carpels lie antero-posteriorly opposite each other, and 
that the incurving of the edges in each takes place towards the central axis of the flower 
—the parts being, while this is in progress, pressed closely together, and involution of the 
extreme edges of the carpels taking place, so that they turn completely inwards, before 
the sides meet—a small space is left between the two ovaries. This space was part of 
the original elliptic space enclosed by the two primitive carpellary outgrowths. If a trans- 
verse section be taken in the region of the base of the two styles, this space appears some- 
what diamond-shaped, while in a similar section, taken higher up at the extreme apices 
of the styles (2. е. where they meet the style-table) in which place the carpellary leaves 
are less perfectly incurved, it has the form of a narrow ellipse. This space has been dig- 
nified by Schacht, Schleiden}, and others with the title of “ the canal of the style ;" but it 
has no functional importance whatever, its occurrence being purely accidental, and it is 
not in any way homologous with “ the canal of the style" which is described as existing 
in Primula'and certain other plants. At the stage when the complete union of the 
apices of the styles has just been effected, a transverse section through the style-table, 
about its middle, shows between the two fibro-vascular bundles a small diamond-shaped 
hole, which, when traced downwards in successive sections, is found to be the last 
remnant of this so-called ** canal of the style," still indicative, like the two fibro-vascular 
bundles themselves, of the original composition of the pentagonal disk-shaped mass. In 
the subsequent stages the walls of that portion of the so-called “ сапа] of the style" which 
exists in the style-table gradually approach each other and completely obliterate the 
ж ¢Bluthen Diagramme,’ 1875, vol. i, pp. 523-529. 
+ Dr. J. M. Schleiden, * Grundzüge, 2nd edition, also * Principles of Scientific un ed. 3, translated by E. 
icr 1849, pp. 356, 359, 377, 379—382, fig. 220. 
2ЕЗ 
