i 5 8 



HARDWICKE'S SCIENCE-GOSSIP. 



of an orchid, and it has been suggested that this 

 acquirement may have been a necessary modifica- 

 tion, in order to assist, by its assumed attractive power, 

 in the means for fertilization, in the absence of some 

 other alluring property, such as nectar ; and, as 

 Mr. Wallace adds, the supposition is rendered all the 

 more probable considering that this is the only species 

 of the genus in South Africa. 



I may now be permitted to call attention, for the 

 first time, I believe, to the special adaptations for 

 cross-fertilization in another irregular-flowered species, 

 viz., Sckizanthns papilionaceus, alluded to above. 

 This plant belongs to the sub-order Salpiglossidea of 

 Scrop/mlarinece (according to Bentham), forming an 

 intermediate section towards which the Figworts and 

 Nightshades approach each other. The inflorescence 

 of Salpigloss-id&r differs from the other two sub-orders 

 of the order in being entirely definite or centrifugal. 

 The plant here mentioned formed one of the two 

 subjects selected by the Science and Art Department 

 for diagnosis in the " Honours " grade in Botany this 

 year ; and there cannot be two opinions that the 

 corolla, which makes the flower so conspicuous and 

 handsome, is particularly easy to describe. The 

 inflorescence is a large loose panicle, or, as it is 

 definite, it may perhaps be more properly defined as 

 consisting of true racemes, arranged upon a loosely- 

 branched floral axis : the individual flowers are some- 

 what papilionaceous, as its specific name indicates, or 

 rather more correctly termed, perhaps, papilionaceo- 

 labrate, the upper or posterior portion of the limb 

 being perfectly erect, whilst the lower anterior, which 

 is three-lobed, forms a horizontal "keel," in which are 

 the two long perfect stamens (fig. 104). The petals 

 of the combined whorl are more or less deeply cut 

 (fig. 105) ; hence the signification in the prefix to the 

 generic name. Similarly we have it in corolla and 

 name in Schizopetalon belonging to the cruciferous 

 order. The lovely flowers of Schizaiithits papi- 

 lionaceus strike one for the first moment as those of 

 an orchidaceous plant, and doubtless the cause of such 

 a development has a similar purpose to fulfil as that 

 of Ajuga ophrydis and other peculiarly abnormal 

 corolline forms. 



Now it will be seen that the position of the two 

 perfect stamens in the keeled lip are in juxtaposition 

 with the style (fig. 104). But the extreme condition 

 of proterandrism appears to prevent self-fertilization, 

 whilst another attendant condition in the way of 

 insect adaptability must evidently favour cross-fertili- 

 zation. This lower keeled portion of the limb is, as 

 I pointed out before, horizontal. When the plant 

 was first brought under my notice, I observed that 

 whilst the two developed stamens in some cases had 

 closely approached the style, the "keel" of those par- 

 ticular flowers had dropped down (fig. 106). I also 

 observed that the anthers in those instances had dis- 

 charged their pollen ; in other words, they had 

 finished their work. Not dreaming of such a thing 



as inherent irritability, I merely shook the flower- 

 stalk, with its numerous flowers, violently in my hand, 

 to notice if motion had anything to do with the 

 bringing about this changed position of keel and 

 stamens. All remained the same, and so at present 

 did the mystery. My books at home afforded me no 

 help, neither did persons of whom I sought informa- 

 tion, until I reached a professional gardener, and 

 seedsman," an old acquaintance, of some half a 

 dozen miles distant, who, to my utter astonishment, 

 was cultivating Schizanthus papilionaceus in pots for 

 the conservatory in abundance ! It was an exquisite 

 floral sight. Having this further opportunity, I 

 examined the flowers again. The "keel" of one of 

 them was slightly touched when we perceived that 

 the two stamens instantly jerked upwards out of it, 

 and closely approached the style ; at the same time 

 the anther-cells burst, expelling the profuse pollen 

 with great elastic force ; simultaneously also the 

 "keel " dropped down as if upon a hinge. 



The problem was now fully solved, and there 

 remains but little for me to add. The points of 

 consideration in the flowers of this plant as affecting 

 a condition opposed to self-fertilization may be sum- 

 marized as follows : — (1.) By the unequal develop- 

 ment of the stamens and pistil (proterandrism). (2.) 

 By the existence of a large area of attractiveness 

 provided by the combined numerously flowered in- 

 florescence, and peculiar structure of the individual 

 flowers. (3.) By the need of mechanical stimulus to 

 disturb the concealed perfect stamens. 



The "keel" forms an alighting stage for the 

 insect, which swings down under the weight of its 

 body, and, especially its underside, becomes at the 

 same time dusted over by the discharged pollen. As 

 the position of the style is parallel with and close to 

 the upper side of the " keel," the insect's body would 

 naturally come first in contact with the stigma of any 

 foreign flower the insect may visit, and if the stigma 

 be in a state far enough advanced, fertilization would 

 be effected. Probably no plant, orchids excepted, 

 affords a more interesting subject for study and such 

 combined appliances, emphatically promoting the end 

 which incontestably supports the Darwinian view 

 that " Nature abhors perpetual self-fertilization." 



Slough. Gf.orge Newlyn. 



P. S.— Since the above has been in type, the Rev. 

 G. Henslow has kindly communicated to me some 

 interesting details of similar observations he has made 

 in the floral structure of a few leguminous plants. — 



G. N. 



How to Destroy Ants. — If Mr. George Pearce 

 uses a mixture in equal parts of calomel and powdered 

 white sugar, he will speedily rid himself of the ant 

 nuisance. — Samuel Woods. 



* Mr. Elliott, of Bray Wick, Maidenhead, who informed me 

 that .S'. pinnatus was very similar toS. f>aJ>ilio>iaccits, both in 

 the structure of the flower and habit of growth. — G.N. 



