192 



SCIENCE-GOSSIP. 



British Mosses. — Part 16 of Mr. Braithwait's 

 " British Moss-Flora," which finishes vol. ii, was 

 published a short time ago and completes the 

 acrocarpous mosses. 



Mimulus Lutens, Linn. — On July 30th, I 

 found growing in a ditch near Wey bridge, in 

 Surrey, several robust specimens of Mimulus lutens, 

 which, though not a native, is naturalised in some 

 parts of England. Impatiens fulva, Xutt, was 

 growing in large quantities on the banks of the 

 Wey, close by. — W. J. Lucas, Knight's Park, 

 Kingston-on-Thames ; August yd 1895. 



Second Flowering of Sallow and Elder. — 

 "Whilst hunting last week for the larvae of Smerinthus 

 ocelatus on Wimbledon Common, near here, I 

 observed that three bushes of the common sallow 

 (Salix capraa) were coming into bloom for the 

 second time this season, one branch having five or 

 six good catkins. All the bushes were male plants. 

 Later in the day an elder-tree was seen blossoming 

 for a second time this summer. The elder-tree in 

 question standing close to Wimbledon Green. — 

 Bertram G. Rye, 281, Fulham Road, London, S.E.; 

 August 15th, 1895. 



An Oak Seedling. — I was much interested in 

 reading the article in Science-Gossip on "An 

 Oak Seedling" (ante page 145). I have now 

 growing in water, in a small bottle, an oak seed- 

 ling from an acorn of 1893. It germinated in 

 the following Spring, and grew a stem four 

 inches high, putting out five leaves. This Spring 

 (1895), ^ grew another two inches, putting out five 

 more leaves. The curious part is, that the first five 

 leaves of 1894 are quite green and show no signs of 

 withering. The two withered cotyledons are still 

 adhering to the base of the stem. The acorn was 

 from the moss-cupped oak. — Athelstan Corbet, 

 Adderley Rectory, Market Drayton ; Augtist, 1895. 



Harmonious Colouring of Wild Flowers. — 

 Referring to my note in your August number (ante 

 page 164) under the above heading, there may be 

 observed, here in West Sussex, further instances of 

 nature's floral harmonies. The banks of the river 

 are fringed with masses of tansy (Tanacetum tulgare) 

 and purple loosestrife (Lythrum salicaria) . These 

 make a gorgeous contrast. On the golf links at 

 Littlehampton, as I suppose on most of our sandy 

 sea-coast commons, flourish and abound, in close 

 juxtaposition, the thrift (Armeria maritima) and the 

 viper's bugloss (Echium vulgare), the pale pink of the 

 one flower according admirably with the bright 

 blue of the other, and both set off by a sprinkling 

 of the yellow mouse-ear (Hieracium pilosella). No 

 artist could have composed a more tasteful and 

 effective harmony than that produced by the 

 intermingling of these three flowers. Will you, or 

 one of your readers, say if there is any scientific 

 reason, such as that suggested in my former note, 

 to account for this rule of colour-harmony in the 

 growth of the wild flowers ? — M. J. Teasdale, 

 FittleiLvrth , Sussex. 



Cuscuta Europoea in Sussex. — I have found 

 this plant growing on nettle and hop behind the 

 old water-mill here. Also a variety (querv var. 

 cambrica) with divided segments, of Poly'podium 

 vulgare. — M. J. Teasdale, Fittleworth, Sussex; August 

 1895. 



Ampelopsis Fruiting. — I have a flourishing 

 Virginia creeper on the house-front, facing south- 

 west. Often in previous years it has produced many 

 flowers and even small fruits, but this season great 

 numbers of the berries have ripened, which has 

 never been the case before. The fruits are like 

 small dark grapes, about a quarter of an inch in 

 diameter, and covered with a similar bloom but 

 without the juicy flesh. I do not know another 

 instance of this plant ripening its fruit in England, 

 *and should be glad to hear if it is at all common. 

 Its near relationship to the grape-vine is verv 

 clearly shown in both flowers and fruit, which are 

 interesting in several respects from a botanical 

 point of view. — J. Burton, 9, Agamemnon Road, West 

 Hampstead. 



Stomata and Sunlight. — The references (ante 

 page 136) with respect to variability in the size and 

 number of the leaf stomata are so far correct and 

 valuable. According to M. Dufour "in sunlight 

 the stomata are more numerous, especially on the 

 upper surface of the leaf, the different elements of 

 the epidermis are more developed, the cells are 

 higher, their lateral and outer walls are thicker 

 and much less sinuous, the cuticle in particular, 

 than in the shade." The leaves of Circaa luteteana 

 have been especially investigated in this connection 

 and it has been found that in the young leaf while 

 in the shade most of the stomata show only a single 

 rounded cell very different from the adjacent ones, 

 in the sun most of them are already divided and 

 many present a stomata opening. The formation 

 of the stomata is due in most cases to a local 

 multiplication of the epidermal cells, followed by 

 an arrest of development, and this process goes on 

 up to an advanced period in the life of the leaf. It 

 is hard to see, however, where the element of 

 protection from the increased heat of the sun in 

 exposed situations comes in. In point of fact, 

 leaves comport themselves almost as opaque 

 screens, the thicker they are the more heat they 

 absorb, while the thinner ones transmit more and 

 absorb less. The only sort of protection that is 

 required in the case is that against a too active 

 transpiration, and this may be effected by a thick, 

 cuticle, closured stomata, a covering of hairs on 

 the under surface, etc., all of which are naturally 

 produced under the influence of strong direct 

 sunlight, which at the same time induces a more 

 active and abundant transpiration. Moreover, 

 according to Lesage, the palisade tissue of the leaf 

 appears to function as a means of protection from 

 excessive transpiration. Now, as is well known, in 

 sunlight this tissue presents a greater development — 

 it cells are more elongated, or the layers of its cells 

 are doubled, as in privet, and they are richer in 

 chlorophyll — than in the shade. Hence we see that 

 an open exposure to strong direct sunlight cuts, as 

 it were, both ways. At the same time while 

 transpiration is rendered more vigorous, the" means 

 whereby its excess may be checked are amply 

 provided by the vital energy of the leaf itself. The 

 plant, therefore, in reality struggles to adapt itself 

 to the environment, and not to select this or 

 that variation as a means of protection, etc. — 

 Dr. P. Q. Keegan, Patterdale, nr. Penrith; August, 

 1895. 



