HARDWICKE'S SCIENCE-GOSSIP. 



8 9 



Experiments on vegetation show that growth and the 

 metastasis in the tissues necessarily connected with 

 it, only takes place so long as oxygen can penetrate 

 from without into the plant. In an atmosphere 

 devoid of oxygen no growth takes place ; and if the 

 plant remain for any time in such an atmosphere it 

 finally perishes. The more energetic the growth and 

 the chemical changes in the tissues, the larger is the 

 quantity of oxygen absorbed and of carbon dioxide 

 exhaled ; hence it is especially in quickly germinating 

 seeds and in unfolding leaf and flower buds that 

 energetic respiration has been observed ; such organs 

 consume in a short time many times their own 

 volume of oxygen in the production of carbon 

 dioxide." Is not this experiment of placing a plant 

 in an atmosphere devoid of oxygen somewhat 

 delusive ? As all the carbon contained in the 

 atmosphere exists in the form of carbon dioxide, I 

 do not quite see how it would be possible to deprive 

 an atmosphere of all its oxygen without eliminating 

 the carbon also, and as it is now supposed that plants 

 derive all their carbon from this source, of course 

 this would be fatal to the growth of the plant in 

 itself. On the other hand, if the carbon dioxide 

 remained, and the experiment were conducted in 

 sunlight, we may be quite sure that the plant, if 

 it contained chlorophyll, would absorb the carbon 

 dioxide and would constantly liberate oxygen, so that 

 if the atmosphere contained no free oxygen at 

 starting, it would not long remain in that condition. 

 That the tissues of every plant contain plenty of free 

 oxygen is well known, but I imagined it was equally 

 well known that this oxygen was derived, chiefly at 

 all events, from the decomposition of compounds 

 containing oxygen, such as water, carbon dioxide, and 

 many other compounds contained in the plant. In 

 the case of germinating seeds and flower-buds, every 

 one knows that they absorb oxygen and exhale carbon 

 dioxide, but I always thought it was universally 

 conceded that this is caused by the conversion of 

 starch into sugar, and is in fact a kind of combustion, 

 a part of the carbon contained in the starch uniting 

 with the oxygen of the air to form carbon dioxide, 

 and not connected in any way with the phenomenon 

 of respiration. Besides, in these parts of the plant 

 assimilation of carbon is not going on, at least I have 

 hitherto thought not. They are expending their 

 substance, not producing it, whereas, if I understand 

 Sach aright, he means to tell us that this process is 

 continually going on in the leaves side by side with 

 the contrary process of assimilating carbon from the 

 air ; in other words, that leaves of plants are con- 

 tinually engaged in taking in carbon dioxide and 

 giving out oxygen, and in taking in oxygen and 

 giving out carbon dioxide at one and the same time, 

 which seems to me a curious conclusion to arrive at. 

 I should be much obliged if you or some other 

 botanist would kindly enlighten my ignorance on 

 this point. — Colonel Dick ins, Winchester. 



Specific Names of British Plants.— There 

 are many specific names, which are nouns in the 

 genitive singular or plural, as Capsella Bursa-pastoris 

 (purse of the shepherd), Dipsacus jullonum (the 

 teasle of the fullers), Convolvulus sepium (convolvulus 

 of the hedges), Vicia sepium (tare of the hedges). 

 The genus Campanula has examples of all the three 

 genders ; thus, Campanula patula, C. trachelium, 

 C. rapunculus. How is this ? It is against some of 

 our school rules, though of course there are exceptions 

 to every rule, and after all the great master (Linne) 

 may be right. — J. F. R. 



The Naturalised Plants in South Aus- 

 tralia. — Dr. Richard Schomburgk has recently pub- 

 lished a small pamphlet on this subject. Among the 

 plants mentioned are the following European species : 

 Common Fumitory {Fumaria officinalis), Common 

 Shepherd's-purse (Capsella Bursa-pastoris), Hedge 

 Mustard (Sisymbrium officinale), Common and 

 Narrow-leaved Pepper-wort (Lepidiuni sativum), 

 Watercress {Nasturtium officinale), Common Winter 

 Cress (Barbarca vulgaris), Chickweed (Stellaria 

 media), Thyme-leaved Sandwort (Arenaria serpilli- 

 folia), Common Mouse-ear Chickweed (Cerastium 

 vulgatum), Corn Spurry (Spergula arvensis), Oleraceus 

 Purslane, Heron's Bill (Erodium cicutarium), White 

 Clover ( Trifolium repens), Common Clover ( Trifolium 

 pratense), Small-flowered Melilot (Mchlotns pand- 

 florus), Lucerne (Medicago sativa), Toothed Medick 

 (Medicago denticulata), Common Vetch ( Vicia sativa), 

 Common Fennel (Fceniculum vulgare), Scotch Thistle 

 (Onopordon Acanthium), Variegated Thistle (Cardials 

 Marianus), Goatsbeard (Tragopogon porrifolius). 

 Chicory (dehor ium Intybus), Common Groundsel 

 (Senecio vulgaris), Golden Corn-flower (Chrysan- 

 themum segetum), Sow-thistle (Sonchus asper), 

 Rough-leaved Sow-thistle (Sonchus oleraceus), Corn- 

 field Sow-thistle (Sonchus arvensis), Red-flowered 

 Pimpernel (A nagallis arvensis), CornGromwell(Z?V/^^- 

 spermum arvense), Blackberried Nightshade (Solanum 

 nigrum), Common Henbane (Hyoscyamus 'niger), 

 Ribgrass (Plantago lanceolata), Knotgrass (Polygonum 

 aviculare), Sheep's Sorrel (Rumex Acetosella), Com- 

 mon and Small Nettle (Urtica urens and Urtica 

 dioica), Black Oat (Avena sativa), Darnel Grass 

 (Lolium temulenlum), Wild Oat-grass (Avena fatua), 

 Early flowering Hairgrass (Aira preecox), Sweet- 

 scented Spring-grass (Anthoxanthum odoraium), 

 Cocksfoot Panic (Panicum Crus-galli), Creeping 

 Dog's-tooth Grass (Cynodium Dactylon), Annual 

 Meadow-grass (Poa annua), Rye-grass (Lolium 

 perenne), Rough Cocksfoot (Dactylis glomeratus), 

 Floating Foxtail-grass (Alopecurus geniculatus), Wall 

 Barley (Hordeum murianum), Small and Great- 

 spiked Quaking-grass (Briza minor and Briza 

 maxima), Barren Blooming-grass {Bromus sterilis), 

 Downy Rye (Bromus commutatus), Soft Brown Grass 

 (Bromus mollis), Hard Fescue-grass (Festuca durius- 



