SCROPHULARINEAE 165 



pollen, behind the stigma. The corolla now becomes detached from the receptacle 

 and falls forward, but remains for a short time suspended to the long style, where it 

 undergoes slight torsion. Finally, it drops with a gyratory motion, and as it does so 

 the stigma must inevitably be brushed by one or other of the anthers lying in front 

 of the mouth of the flower.' {Cf. also V. phlomoides.) 



Visitors. — Redtenbacher observed the Curculionid beetle Cionus blattariae F. 

 at Vienna. 



641. Calceolaria L. 



Correns (Jahrb. wiss. Bot., Berlin, xxii, 1891) describes the nectaries as beset 

 with long-stalked glandular hairs, producing a characteristic secretion, and in some 

 species with chloroplasts (more rarely chromoplasts) in their stalk-cells. Correns 

 thinks that the latter make the nectaries more conspicuous and also by means of 

 carbon assimilation provide the necessary materials for building up the secretion. 

 The stamens somewhat resemble those of Salvia officinalis, but with much simpler 

 hinges, and devoid of specific mechanical cells. 



2052. C. hybrida (?). — Correns (op. cit.) says that in this species the 

 connective is immovably united with the filaments. The style projects obliquely 

 downward between the paired anthers, and the vaulted upper lip is drawn over 

 it as a protection. The lower lip is not in contact with the upper one, so that 

 without moving it to any extent an insect visitor will first touch the stigma and 

 then the anthers, thus effecting cross-pollination. 



2053. C. scabiosaefolia Sims. — Correns states that the flower mechanism 

 of this species is the same as that of C. pinnata {vide infra). The upper and 

 lower lips, as seen from below, are completely apposed. 



2054. C. Pavonii Benth. (Kerner, ' Nat. Hist. PL,' Eng. Ed. i, II, p. 380.)— 

 The protogynous flowers of this South American species are at first almost hori- 

 zontal. The receptive stigma lies on the excavated lower lip, of which the 

 concave middle lobe secretes nectar. The upper side of it is used by short- 

 tongued Hymenoptera as an alighting-platform, and it sinks down as soon as 

 they settle, thus not only widely opening the throat of the corolla, but also 

 displaying the nectar-secreting lobe, which was previously concealed. This enables 

 the dorsal surface of the visitor to brush against the stigma, effecting cross- 

 pollination if an older flower had previously been visited. For in the latter 

 dehiscence has taken place, and the connectives are so articulated with the 

 filaments that when an insect strikes against the anthers they are swung round 

 and the mealy pollen falls upon its back. This effect is ensured by elongation 

 of the connectives, so thct the upper anther-lobes come to lie on the uppermost 

 convexity of the lower lip. Should insect-visits fail, part of the pollen falls upon 

 this convexity, and, as the peduncle curves down in late anthesis, slides down the 

 lower lip, now sloping sharply downwards, to the still receptive stigma. 



2055. C. pinnata L. (Hildebrand, Bot. Ztg., Leipzig, xxv, 1867, p. 284; 

 Correns, Jahrb. wiss. Bot., Berlin, xxii, 1891, pp. 241-52.) — Hildebrand and Correns 

 state that in the flowers of this Peruvian species a pair of anthers are modified 

 into two-armed levers, as in Salvia. One arm with its sterile anther-lobe lies in 



