ALLUREMENTS OF ANIMALS FOR THE DISPERSION OF POLLEN. 175 



incana), in Alysswm, Schiverekia, and Thlaspi such warts are seen right and left 

 of the two short stamens, and in Alliaria and Draha one wart projects from the 

 longer pair of stamens from the outer side facing the corolla. It must remain 

 uncertain whether these structures are to be regarded as part of the stem or as 

 metamorphosed leaves. In many cases — as, for example, in Haberlea, Fcederota, 

 and Polemoniura, where the ring-shaped cushion is divided into five, and in 

 Scrophularia, where it is divided into two symmetrically-placed lobes — the appear- 

 ance is in favour of the latter view. In the flowers of the Bindweeds (Con- 

 volvulacese) the base of the ovary is surrounded by five thick honey-secreting 

 scales of equal size, which together form a small cup reminding one of an egg in 

 an egg-cup, and in the Crassulaceee a little knob or a fleshy scale projects from the 

 circular wall of the base of the flower opposite each carpel, sometimes spoon-shaped 

 (Sedum annuumi), sometimes linear and split at the free end (Seduvi atratum), 

 and of other varied forms. In these instances the honey-secreting structures are 

 without doubt to be regarded as metamorphosed leaves. 



Instances are comparatively rare where the formation of honey is carried on 

 by the carpels — as, for example, the flowers of several Primulacese (Andi^osace, 

 Aretia), in which the slightly arched roof of the ovary secretes minute drops of 

 nectar, and in those of many Gentians {Oentiana acaulis, asclepiadea, Bavarica, 

 Pneumonanthe, prostrata, punctata, &c.), where the bulb-like, thickened base of 

 the ovary exhibits five cushions which exude abundant honey into the base of 

 the flower-tube. In the flowers of some Liliacese and Melanthaceee (e.g. Alhuca, 

 Ornithogalwm, Toßeldia), the honey is secreted in the lateral grooves of the 

 ovary, and in the flowers of Anthericum as well as of AUium Chamcemoly a small 

 depression is found on each of the three lines of union of the carpels from which a 

 drop of honey is poured. 



Nectaries are found much more frequently on the stamens. They occur there 

 in all sizes and shapes. Sometimes it happens that whole stamens are changed 

 into nectaries, which of course can only be at the expense of the anthers. The 

 stamens of the Whortleberry and Bog- whortleberry (Vaccinium Myrtillus and 

 uliginosw^n), like those of Tulips {Tulipa), have a small depression which secretes 

 honey on the broad thickened base of the filament opposite the corolla. In thf 

 widely-distributed Meadow Saflron {Colchicum autumnale) there is an orange- 

 coloured honey-secreting body on the stamens just above the place of union 

 with the violet leaves of the perianth, and the honey there formed fills a channel 

 which traverses the adjoining perianth-leaf. The same thing occurs in other 

 Safirons and also in the genus Trillium. In Geraniaceous plants, especially in 

 Erodiuin and Geranium,, a wart-shaped, sometimes hollow, nectary arises on 

 the base of each of the five inner stamen-filaments on the side directed towards 

 the sepals. The nectaries at the base of the thread-like filaments of many 

 Caryophyllaceae exhibit an immense variety of form. Sometimes all the stamens 

 of a flower are a little thickened at their root, and secrete honey from a yellow 

 tissue opposite the ovary (e.g. in Telephium Imperati), or a pair of honey-secreting 



