SCROPHULARINEAE 231 



the anther-hairs. The right way to the nectar is indicated by the nectar- 

 groove on the corolla-tube and pistil already mentioned, and if this way is 

 followed, not only contact with the stigma (in the first stage) but also with the anther- 

 appendages (in the second stage) must take place. Another guide is provided by sharp 

 projections covering the filaments below the anthers, so that any deviation from 

 the proper direction would result in painful injuries to an insect's proboscis. 



The humble-bee visitor first clings tightly to several flowers, then grasps the 

 lower lip with its forelegs and pushes its head into the mouth of the flower, which 

 is narrowed by the stamens to a slit about a mm. wide. In a flower with ripe 

 anthers the visitor is sprinkled with pollen, and the part of its body thus dusted will 

 touch the receptive stigma of the flowers in the second stage. 



Kerner adds a third stage of anthesis. After the style and stigma have 

 completely withered, the stamens continue to elongate, so that the anthers protrude 

 from the flower. These, which have so far been bound together, now become 

 separate, and the pollen, if it has not already been removed by insects, will be blown 

 away in a little cloud by the wind. It is carried to the still receptive stigma of the 

 upper flowers, and thus fertilizes them geitonogamously. Warnstorf describes the 

 pollen-grains as white in colour, rounded ellipsoidal, and smooth, with three 

 longitudinal grooves, on the average 46 /x long and 30 /* broad. 



Visitors. The following were recorded by the observers, and for the localities 

 mentioned. 



Knuth (Kiel), the 3 commonest German humble-bees, all skg. i. Bombus 

 hortorum Z. 5 ; 2. B. terrester Z. j ; 3. B. lapidarius Z. $. Hofmeyr (Bremen), the 

 humble-bee Bombus agrorum F. 5. Alfken (Bremen), an ant (Myrmica sp.). 

 Stadler, 2 humble-bees Bombus terrester Z., and B. muscorum F. ('Beitrage z. 

 Kenntniss d. Nektarien '). 



676. Clandestina L. 



2179. C. rectiflora Lam. (= Lathraea Squamaria Z., according to the Index 

 Kewensts). (Kerner, 'Nat. Hist. PI.,' Eng. Ed. i, II, p. 331.) This species agrees 

 to a large extent with Lathraea squamaria. It is indigenous to Belgium, West 

 France, and South Europe. Loew (' Bliitenbiol. Floristik,' pp. 302-3), who 

 examined plants growing in the Berlin Botanic Garden, found them more feebly 

 protogynous than those of Lathraea. The tubular calyx is about 19 mm., the 

 galeate, violet upper lip of the corolla 22 mm., and the three-lobed, dark-brown- 

 violet lower lip 1 3 mm. long. The style is bent down like a hook, and the stigma 

 projects 4 mm. beyond the upper lip. In the first (female) stage the anthers are 

 completely enclosed by the upper lip, and the stigma can only be cross-pollinated. 

 In the second (male) stage the edges of the upper lip, hitherto closed to a narrow 

 slit, expand, so that the now mature anthers are accessible. The latter always 

 possess two acuminate hairy processes, and are held together in pairs by short tufts 

 of hair. The ovary is laterally compressed and traversed by a longitudinal groove : 

 the front of its base bears the three-lobed nectary. The way to the nectary is 

 limited, during the first stage, to a deep groove down the middle of the inner surface 

 of the lower lip. The stigma corresponds in position to the upper end of this, and 

 must therefore be brushed against by visitors. In the second stage, the entrance is 



