236 



HAPtDWlCKE' S SCIENCE-GOSSIP. 



S. coronopus as to distinguish the species at first 

 sight, the extremely powerful, pungent odour of 

 S. clidyma—di, point not mentioned by some of our 

 best botanists— at once gives information of it to the 

 olfactoiy organs. — F. H. Arnoldy LL.B., Fishbourne. 



CiciioRiuii Intybus.— Chicory, or wild succory, 

 is very common on the Oolites, both in Gloucester- 

 shire and Dorsetshire, and its striking blue flowers 

 are always attractive. We know that most plants 

 with blue flowers have a tendency to produce white 

 ones, but we never saw any white-flowered chicory 

 before to-day, when our children brought in a 

 quantity from the village. — /. B., Bradford Abbas. 



Valeria>'a Phu.— I am greatly obliged to 

 " J.P.Il." for identifying this plant. As regards its 

 popular or provincial name "Sid well" {qy.Seedwell), 

 I am quite sure that this name is applied to this plant, 

 and not to the Faleriaria off! ci/ia I is, •which is \ery 

 well known here, from the fact of its growing 

 plentifully in Cranborne Chase woods, from whence 

 the country druggists were formerly supplied by the 

 neighbouring peasantry with the root, and may be 

 still, for aught I /know. The " Sidwell," is not a 

 common garden plant ; I know of only two in the 

 cottage gardens here, the leaves of which are in 

 great repute with the doctoresscs as a healing 

 application to wounds and sores. — JF, Smart, Cran- 

 borne. 



Polled"- Grains and the Pektilization of 

 Flowers.— This was the subject of a very inter- 

 esting paper read at the meeting of the British 

 Association in Eelfast, by Mr. A. W. Bennett. The 

 author dealt with the form of pollen-grains in re- 

 lation to the fertilization of flowers. He said that 

 although, not unfrequetnly, a common form of 

 pollen-grain runs through a whole group of plants, 

 yet more often the form is found to be adapted to 

 the requirements of the species, and varies even 

 within a small circle of affinity. In those plants 

 which are fertilized by the agency of insects there 

 are three general modes in which the form of the 

 grain is adapted for the purpose. "We have firstly 

 — and this is by far the most common form — an 

 elliptical grain, with three or more longitudinal 

 furrows, as in Fianidiculus ficaria, Aucuha japonica, 

 and Bryonia dioica ; secondly, spirical and ellip- 

 tical, and covered with spines, as in many com- 

 posite malvaj ; and thirdly, where they are attached 

 together by threads or viscid excretion, as in 

 Richardia icthiopica. In those plants, on the 

 contrary, which are fertilized by the agency of the 

 wind, as most grasses, the hazel, and Populus bal- 

 samifera, the pollen is uniformly perfectly spiral 

 and unfurnished with any furrows, and is generally 

 moreover very light and dry. The genus Fiola 

 supplies two very markedly different, in which the 

 quoins have the. ordinary elliptical .three-furrowed 



form, and where every point of the structure of the 

 style and stigma is favourable to fertilization by 

 bees. In all Crucifers known tl>e pollen has the 

 most common form. In the cowslip and primrose 

 there is uniform difference in size between the 

 pollen belonging to the two forms, that of the 

 short-styled being considerably larger than that of 

 the long-styled form. 



Parthenogenesis in Ferns.— Dr. Farlow, of 

 Harvard University, has recently read a paper on 

 " An Asexual Growth from the Prothallus of Pteris 

 serrulata " — an Indian fern. As is well known, a 

 fern comes to fructification and produces spores 

 without any fertilization. The spores, in ger- 

 minating, produce a liverwort-like frond, the pro- 

 thallus, on which the two kinds of sexual orgaus 

 are developed. The fertilization of a cell in the 

 one by a spermatozoid from the other results in the 

 development and growth of the former into a bud, 

 and so into a fern. Dr. Farlow discovered, in a 

 sowing of the spores of the Pteris serrulata, pro- 

 thalli which were developing young ferns from 

 their substance quite apart from any archegonium, 

 starting in a different way by a direct outgrowth 

 from the prothallus, beginning with a scalariform 

 duct, but producing plantlets thus far undis- 

 tinguishable from those which arise from an arche- 

 gonium through fertilization. Dr. Farlow, con- 

 fining himself strictly to the facts of the case and 

 their direct interpretation, does not use the word 

 " parthenogenesis." But Dr. Asa Gray thinks the 

 case substantially analogous to that of Partheno- 

 genesis in flowering plants. He says that if it be 

 demurred that the case is one of bud-growth, and 

 therefore not of the nature of parthenogenesis 

 proper, the reply is that it comes from a partheno- 

 genetic spore, which here develops plants without 

 the sexual fertilization of that class of plants. If 

 the facts hold good, the conclusion is that sexual 

 fertilization, however necessary, is not absolutely 

 necessary in every generation of plants ; somewhat 

 as cross-fertilization, however necessary in the long 

 run, is generally unnecessary in every generation ; 

 only the rule in the former is far more strict. 



GEOLOGY 



The Thermal Conductivity of Certain 

 Hocks. — Professor A. S. Herscliel, F. R. A. S., and 

 Mr. G. A. Lebour, F. G. S., in a report read at the 

 recent meeting of the British Association, showed 

 that during the past year the relative conductivity 

 of about thirty kinds of rock has been determined. 

 Among these granite has been found to offer the least 

 resistance to the passage of heat, and coal the 

 greatest. Shale comes next below coal ; but between 

 these two and basalt there is a gap of considerable 



