260 



OEGANOGBAPHT. 



Fig. 570. 



of the flower, the andrcecium and floral envelopes being ar- 

 ranged around it when they are present {fig. 419) ; the floral 

 envelopes alone in the pistillate flower; or it stands alone when 

 the flower is pistillate and naked {fig. 389). The gyncecium 

 consists, as we have seen, of one or more modified leaves called 

 carpels, which are either distinct from one another, as in the 

 Stonecrop {Sedum) {fig. 566) ; or combined into one body, as 

 in the Primrose {Primula vulgaris), {fig. 567), and Tobacco 

 {Nicotiana Tahacum) {fig. 569). When there is but one carpel, 

 as in the Pea and Broom {fig. 568), the pistil is said to be 

 simple ; when there is more than one, as in the Stonecrop, 

 Tobacco, and Primrose, it is compound. Before proceeding to 

 examine the gyncecium or pistil generally, we proceed in the first 

 place to describe the parts, nature, and structure of the carpel 

 of one or more of which it is composed. 



The Carpel. — This name is de- 

 rived from a Greek word signifying 

 the fruit, because the pistil forms, 

 as will be afterwards explained, the 

 essential part of that organ. Each 

 carpel, as we have already noticed, 

 consists, 1st, of a hollow inferior 

 part arising from the thalamus, 

 called the Ovary {fig. 570, o), con- 

 taining in its interior one or more 

 little roundish or oval bodies called 

 ovules, ov, which ultimately become 

 the seeds, and which are attached 

 to a projection on the walls termed 

 the placenta, p. 2nd. Of a stigma 

 or space of variable size, composed 

 of lax cellular tissue without epider- 

 mis ; the stigma is either placed 

 directly on the ovary, in which case 

 it is said to be sessile, as in the Bar- 

 berry {Berberis vulgaris) {fig. 570, 

 st) ; or it is elevated on a stalk 

 prolonged from the ovary, called 

 the sU/le {fig. 568, s). The only 

 essential parts of the carpel, there- 

 fore, are. the ovary and stigma, the 

 style being no more necessary to it 

 than the filament is to the stamen. 

 The terms ovary, style, and stigma, 

 are applied in precisely the same sense when speaking of a com- 

 pound pistil in which the parts are completely united {fig. 569), 

 as with the simple carpel. The ovary has two sutures, one of 

 which corresponds to the union of the margins of the lamina of 

 the carpellary leaf out of which it is formed, and which is 



Fig. 570. Vertical 

 section of the 

 ovary of the 



rry ( Berberis 

 l•llh/(lris^, on tiie 

 outside of wliich 

 are seen a sta- 

 men aud petal, o. 

 Ovary. oiJ. Ovules 

 attached to a 

 projection called 

 the placenta, st. 

 Stigma. 



Compound pistil of 

 Tobacco (Nicotiana Tabacum). 

 t. Thalamus. o. Ovary, s. 

 Style, fir. Capitate stigma. 



