174 



NA TURE 



\June 2 2, 1876 



upwards (hence the stigma looks upwards or even obliquely 

 backwards) ; on the morning of the second day it is 50 mm. 

 long, straight, and the stigma looking forwards ; by the 

 morning of the third day the flowers bend aside and wither. 

 Consequently on the first day the anthers, on the second day 

 the stigmas are more liable to be struck by the wings of 

 the butterflies, although the stigmas seem to be capable of 

 being pollinated already during the opening of the flower. 

 The pistil, as in other species of Hedychium, is inclosed 

 in a completely closed channel of the corolla tube (Fig. 

 90) and of the filament (Fig. 91) ; the funnel-shaped 

 stigma (Fig. 92), secreting plenty of fluid and bordered 

 with hairs (Fig. 93), slightly overtops the anther (Fig. 

 89, St). 



By the morning of the second day all bees and butter- 

 flies with a proboscis of more than 10 mm. long would 

 be enabled to obtain at least a little portion of the very 

 sweet honey from out the opening of the corolla- 

 tube ; whereas from the more conveniently situated 

 opening of the lip-tube the full store of honey can be 

 reached only by a single species cf the butterflies of 

 Itajahy (as far as their proboscides have been measured 



Fie. 89. — Hedychium. Two alternating whorls, each consisting of three 

 groups, each group containing from four to six flowers, of which only 

 one or two are developed. Half natural size. i. Flowers on the first 

 day. 4. Flowers on the second day. In most flowers only the lip and 

 the stamen with the stigma are drawn, a, anther ; .;/, stigma. 



by my brother), namely, the males of Callidryas Philea, 

 with a proboscis from 36 to 43 mm. long.-^ 



This was indeed the most assiduous of all visitors. It 

 was always sucking out of the lip. Scarcely less frequently 

 were the flowers visited by Callidryas Etibule $ , always 

 sucking in the same way, with a proboscis from 27 to 

 30 mm. long (a female, caught on these flowers, had a 

 proboscis only 24 mm. long). Callidryas Trite ^ , on the 

 contrary, with a proboscis 18 to 20 mm. long, seems always 

 to suck immediately out of the corolla-tube. Callidryas 

 Statira ^ (19 to 21 mm.) mostly sucks in the same way ; 

 but sometimes also from out the lip. Callidryas Argante 

 being very rare during the flowering time of this Hedy- 

 chium (towards the end of January) was only occasionally 

 seen visiting its flowers, and it was not observed in 

 what way it reached the honey. Dark yellow, orange, 

 scarlet, red, are the favourite colours, not only of the 

 Callidryas but likewise of the Agraulis{Dione) and of some 



' The proboscis of the female seems to be not so long ; in two females 

 measured by my brother it did jiot exceed 35 mm. 



species of Papilioj of the former, Agraulis vanillce (pro- 

 boscis 15 mm.) visited the flowers several times, but soon 

 flew away again. Of species of Papilio, P. Thoas (26 mm.) 

 appeared especially frequently, as also several times P. 

 Palydamas (24-25 mm.), P. Cleotas 22-23 mm.) three 

 times, and once P. Protodamas (?) (22 mm.) ; these mostly 

 fluttered upwards along the rows of flowers without settling 

 down ; it was not distinctly seen from which opening 

 they obtained the honey. 



Another adaptation of the flowers to cross-fertilisation 

 by butterflies must be mentioned. A wing of a butterfly is a 

 tolerably smooth plain, moving rapidly when flying ; the 

 pollen-grains of Hedychium are likewise smooth ; these 

 peculiaiities are ill adapted to each other ; but this incon- 

 venience is removed by the anthers not bursting, but 

 their anterior- surface dissolving into a 1 lyer of slime which 

 covers the pollen-grains and glues them to the wings. 



Of Apidae my brother once saw Xylocopaj it attempted 

 to suck from the lip, but after having made some fruitless 

 trials flew away again. He repeatedly met with Bombus 

 violaceus and Cayennensis, rarely, however, compared 

 with their frequent visits to other flowers, for instance, 

 the neighbourin;; bushes of Buddleia, They sucked from 

 out the corolla tube. B. violaceus was several times ob- 

 served to alight on the lower flowers of a longitudinal row, 

 climbing from there up the row more or less completely, 

 then flying to another spike. In consequence of this 

 systematic manner in which the most intelligent bees ex- 

 plore the flowers of a plant, the fertilisation by bees of a 

 plant with such a number of flowers as our Hedychium 



Fig. 90. Fig. 91. Fig. 92. Fig. 93. 



Fig. 90. — Transverse section of the coroila-tube, 15 : i. Fig 91. — Trans- 

 verse section of the filament enclosing the pistil. Fig. 92. — The stigma 

 bordered with hairs. Fig. 93.— A single one of these hairg. 



must be by far less advantageous than the fertilisation by 

 butterflies. Suppose a specimen of this Hedychium bearing 

 twenty spikes, each with fifty flowers, a humble-bee would 

 be likely to visit 1,000 flowers without effecting a single 

 cross-fertilisation between different plants, consequently 

 without any profit for the plant, which is sterile with its 

 own pollen. On the contrary, on flowers copiously visited 

 by butterflies, the same butterfly will rarely visit a greater 

 number of flowers of the same plant continuously ; and 

 this holds good, not solely, as Delpino has already re- 

 marked, with females which are followed by the males. 

 On a Hedychium, males of Callidryas only were flying 

 (females being then very rare), but, nevertheless, as soon 

 as any butterfly was approached by another of the same 

 or even of a different species, it flew up, ran and whirled 

 with it about in the air, and then alighted commonly on 

 another bush. 



Lastly, there appeared repeatedly several species of 

 humming-birds, one of which was so absorbed in sucking 

 the honey that it could be caught with a net, which my 

 brother had never before succeeded in doing. In the 

 corolla-tube of this Hedychium small insects have never 

 been found by my brother ; the perseverance with which 

 the humming-birds made use of its flowers proves, there- 

 fore, in case such a proof should still be needed, that 

 these birds were here searching for honey. 



It may be remarked in addition that humming-birds are 

 far less exclusively attracted by the bright red colour of 

 flowers than Callidryas ; and, as these butterflies are 



