Mat 1, 1S70.1 



HARDWICKE'S SCIEN CE-GOSSIP. 



Ill 



HAIRS OF SUN-DEW. 



IN the volume of Science-Gossip for last year, 

 I was interested in some notices of Sun-dew 

 (Brosera rotundifolia, L.), and, as the writers did 

 not express some interesting - facts which came 

 under my notice during the past year, I venture 

 to address a few lines to your readers, even from 

 this side of the Atlantic. This charming little 

 plant appeals so strongly to our sense of the beau- 

 tiful, that I have been enticed to examine the 

 habit of its leaves, and also the structure of the 



Fig. 121. Glands of Drosera rotundifolia. 



1. Oval gland of Drosera rotundifolia, x 130. 



2. Cylindrical gland (front view) of D. r., x 130. 



3. Ditto (side view) of D. rotundifolia, x 130. 



glands which are found on them. I think even 

 botanists are not aware that two distinct kinds of 

 glands are to be found on the leaves of the Sun-dew ; 

 at least, I have never seen the fact alluded to in the 

 books. The rather rude drawing I have made of these 

 glands under the camera-lucida may help to give 

 an idea of their form and beauty. Tig. 1, x 130, is 



designed to represent the oval gland found chiefly 

 on the upper surface of the leaf, and also on its cir- 

 cumference. Large spiral cells fill up the centre of 

 each, and on these spiral cells rest others of colum- 

 nar form ; while all over its entire surface the sticky 

 excretion abounds during the active life of the plant. 

 The new glands, to which I would direct the atten- 

 tion of microscopists interested inbotanical pursuits, 

 are represented by figs. 2 and 3, and are to be 

 found on long filaments surrounding the circumfer- 

 ence of the leaf. They unfold sooner than those of 

 oval shape, and are sooner to fade. These, too, have 

 large spiral cells in the centre, but in fig. 3, which 

 gives a side view, we observe the columnar cells 

 occupy only the concave or inner side, and only on 

 this surface is the sticky excretion to be found. 

 Eig. 3 represents a front view of these cylindrical 

 glands, after the preparation has been rendered 

 transparent enough to enable its entire structure to 

 be seen at one view. The drawings are represented 

 magnified 130 diameters, so that a comparative view 

 might be given of their relative size, ^ew objects 

 in plant anatomy are more beautiful than these singu- 

 lar organs, when properly prepared, and it would 

 give me pleasure to send a few slides of them to the 

 editor of Science-Gossip, who is doing such good 

 work in circulating among us the exchangeable facts 

 of popular science. That the leaves or hairs of the 

 Sun-dew are endowed with contractile irritability I 

 have doubts. In many instances I have placed them 

 under a lens, and with a needle's point touched every 

 part, but never succeeded in obtaining any evidence 

 of the fact. And often in their native bogs I have 

 found pollen-grains of the pine nestling unclasped 

 between the sticky gland. A dead ant or other 

 small insect placed carefully on the leaf in every 

 instance failed to elicit any entomological propen- 

 sity whatever. But a living insect, exposed in the 

 same position, soon drew around it many filaments 

 and glands, which appeared to adhere because of 

 their sticky covering, rather than from any contrac- 

 tility they might possess. It would seem to be, 

 therefore, the struggles of living insects endeavour- 

 ing to escape that cause many glands to surround 

 them, rather than any special contractility in the 

 leaves or hairs. I have often obtained new plants 

 of the Sun-dew by depositing the matured leaves on 

 wet sand, and, after a short time, have found adven- 

 titious buds developed, which soon grew up into 

 perfect plants. On the fruiting spikes, during and 

 after inflorescence, I have found whorls of 

 similar leaf-buds developed, which also have been 

 followed by charming circles of new leaves ; thus 

 giving our attractive subject the appearance of 

 one plant rising on the decaying ruins of another — 

 beauty from decay, and life from what we call 

 death.— Dr. J. G. Hunt, President of the Natural 

 History Club, §~c, Philadelphia, Pennsylvania; 

 U.S. 



