i58 



HARDWICKE'S SCIENCE-GOSSIP. 



towards the main stem of the gorse. The root is, 

 however, capable of producing more than one new 

 tuber at the same time or during the same season, as 

 I have frequently found after careful examinations of 

 old plants that there were two and in some cases 

 three new tubers formed, and ready for advancing 

 into active growth in spring. They are usually 

 attached to the roots of the gorse at a depth of from 

 four to six inches, and never, that I have seen, above 

 ground level. 



The propagation by seed is a very slow process, 

 these usually requiring three and in not a few cases 

 four years to produce flowering plants. The plants 

 never appear above ground until of a flowering size, 

 which will readily account for the absence of young 

 specimens — a fact which has frequently been noted 

 and commented upon by accurate observers. As all 

 the specimens examined were, as above stated, 

 growing on the gorse roots at a depth of from four to 

 six inches, I have often been puzzled to satisfactorily 

 account for how the seeds penetrate to such a depth. 

 The only probable explanation, and one that will also 

 account for the greater abundance of the plant in 

 gravelly porous ground, is that the seeds, being very 

 minute, are readily washed downwards by the heavy 

 rains through the loose sandy soil in which the plant 

 delights to grow. 



That this plant is parasitical, and not epiphytal, as 

 supposed by some, I have repeatedly proved beyond 

 a doubt, for on carefully digging up the root it will 

 be found impossible to sever it from that of the furze, 

 and even when cut across at point of attachment 

 both seem so perfectly united as to appear like one. 

 I also think it is an error to figure this plant as it is 

 in most floras with rootlets at the point of parasitical 

 attachment, as these, although I have gone to a great 

 amount of trouble in grubbing up plants to find if 

 such really was the case, I never could detect. 

 Certainly there are rootlets, as those of other plants 

 seem to have a particular affinity for working their 

 way between the loose outer scales of the tuber of 

 this plant. The root of the furze also sends out tiny 

 rootlets which may readily be mistaken for those of 

 the orobanche. 



That part of the furze root where the attachment 

 takes place is much enlarged, but outward from 

 that point it dies off, no doubt from the circulation 

 of the sap being averted by the parasitic growth. 

 The plant flowers in May and 'June, the period 

 being however, greatly extended in some specimens. 



From observations made for a number of years I 

 have every reason to believe that in a dry, warm 

 season this plant attains to greater perfection, and 

 remains undestroyed for a much longer period than 

 during dull, damp weather. The largest specimen 

 I have found measured thirty-eight inches in length, 

 had a stem one and a quarter inches in diameter, and 

 bore ninety-nine flowers. 



This gigantic specimen I have carefully preserved 



as a memento of the plant. The average size in this 

 district when growing under favourable circumstances 

 is, however, from two to two-and-a-half feet in 

 height. 



The lesser broom-rape (O. minor), though smaller 

 in all its parts, very nearly approaches in general 

 structure the former species, indeed it is questionable 

 if these two species are specifically distinct, as the 

 different plants on which the orobanche grows seem 

 to alter the nature of the so-called species in a 

 remarkable degree. As the name indicates, this 

 plant is usually of smaller growth and more slender 

 than O. major, and with more or less of a blue tinge 

 in the flower, but this is by no means constant, as 

 forms with pale yellow and deep blue flowers are not 

 uncommon. This species seems to be by no means 

 particular as to the plant on which it grows, having 

 been found somewhat plentiful on our common ivy, 

 clover, the Eryngium, &c, and varying much 

 according to the plant, as well as situation, in which 

 it is found — this having no doubt given rise to the 

 several varieties into which the plant has been 

 divided ; but the differences between these varieties, 

 or rather forms, are so minute and inconstant as to 

 be deemed unworthy of separate remarks. It occurs 

 sparingly in this country, and is more generally 

 found on the turf than any other plant. 



Two other species very nearly approaching the 

 latter are the clover-scented and red broom-rapes 

 (O. caryophyllacea and O. rubra), the former 

 parasitic on galiums and the latter on thyme. It is 

 generally believed, indeed has been recorded on the 

 highest botanical authority, that 0. rubra is not 

 parasitic, and that the plant is exclusively confined to 

 basaltic rocks, such as those of the north of Ireland 

 and east coast of Scotland. That neither of these 

 statements can, however, be accepted as wholly 

 correct, the following interesting and valuable inform- 

 ation, kindly furnished by Mr. Lindsay, curator of 

 the Royal Botanic Gardens, Edinburgh, only too 

 plainly shows. Mr. Lindsay says, " In reply to your 

 note regarding Orobanche rubra being parasitic, I 

 have to say that it is so, and think there can be but 

 little doubt that the other species are parasitic also. 

 In the rock garden here, O. rubra has become 

 thoroughly established, self-sown plants have come 

 up in different directions, but always on some species 

 of thymus, oftenest on T. serpyllum, never on any 

 other kind of plant." I have no doubt that this plant 

 is more abundant in Britain than is generally 

 supposed, but the inconspicuous appearance, and out- 

 of-the-way places in which it is usually found, as well 

 as general resemblance to O. major, have all much to 

 do in accounting for the supposed rarity of O. rubra. 



The branched broom-rape (0. ramosa) is a rare 

 British species, being almost confined to a few of the 

 southern English counties. This and the blue broom- 

 rape (0. cczrulea), the former in particular, are the 

 only members of the family having branched or 



