SCIENCE-GOSSIP. 



io 5 



CONTRIBUTIONS TO THE LIFE-HISTORIES OF PLANTS. 



By Thomas Meehan. 

 (Concluded from page 8oJ 



Flowers and Flowering of Lamium purpureum. 



ONE might suppose that a plant so widely spread 

 over the world, and one that intrudes itself 

 so persistently on everyone's attention, as Lamium 

 urium, could not possibly have anything written 

 about it that would be new to botanists. But I am 

 inclined to believe that plants have not a uniform 

 behaviour in even- place, and possibly the be- 

 haviour of species here may be different from that 

 in the Old World. These considerations make it 

 the more important that the points I have noted in 

 the plants growing on my grounds should be placed 

 on record. 



The species is very abundant as a weed on my 

 grounds near Philadelphia. It is the form with 

 the smaller, flowers and without the ring of hair 

 below the throat that is described in the typical 

 form of Europe. It was originally introduced into 

 my grounds from Germany. It is probably the 

 form which Willdenow regards as a good species 

 and describes as Lamium incisum. The hair that 

 is found in the throat of L. purpurcum is absent, 

 there is but a single short tooth instead of two on 

 the lower lip, and the pollen is orange instead of 

 bright scarlet. 



Dr. Bromfield notes " anthers with several tufts 

 of stiff hairs or bristles on the face of each cell, and 

 according to Mr. Leighton accompanied by six 

 :.;ht small, white, oval, tuberculate bodies at 

 their base, but of which I can find no trace in my 

 specimens, and presume they are, therefore, not 

 constantly present." These tubercles are only on 

 one side of the anther and are easily overlooked. 

 There are always six of these, so far as I have 

 examined them ; they are, however, easily over- 

 looked as they are on one side only, as already 

 .1. They are very beautiful as seen under a 

 lens, but I have been unable so far to trace their 



ty on 



the A the tubs near thi 



ha-. ad may also throw some 



light on the structure of the flower. 



peculiarit) ifter the 



. i the receptacle, 



i the carpel, at the 



«arr. .In 



.ifi'-r 



ll« fade*, the corolla usually yard 



any articulation by 

 which the style »c; m the carpel* ai in 



thi 



This early fading of the flower and casting off of 

 the pistil indicates that the flower may have been 

 fertilized before the opening of the lobes of the 

 corolla. An examination shows that this is really 

 the case. When the flower is fully expanded the 

 stamens are straight, bearing the anthers under the 

 arched under lip. The anthers will usually be 

 found destitute of pollen, while the longer lobe of 

 the divided style will be found with an abundance 

 of orange- coloured pollen at the apex. It will 

 further be noted that from the relative position of 

 the forks of the style and the anthers, the pollen 

 could not readily reach this portion of the style 

 while in the fully expanded condition of the flower. 



If we take a matured flower-bud, just ready for 

 expansion, and carefully cut away the upper lip, 

 we find no stamens there at that stage. They, as 

 well as the style, are bent downward, grasped and 

 held in place by the incurved lower lip. Examining 

 these unopened flowers in the early morning we 

 find the anther cells have already opened and the 

 sharp stigmatic point of the lobe of the style in 

 most cases is inserted in one of the anther openings 

 and covered with pollen. Between eight and nine 

 o'clock in the morning the unopened buds unfold. 

 Slowly the incurved stamens and style straighten 

 themselves and rise to their final positions under 

 the arched upper lip. During this process the 

 stigmatic lobes are brought into contact with the 

 disrupted pollen sacs, and receive an additional 

 supply of fertilizing material, as if nature was 

 taking a double care in this instance that the flower 

 should be self-fertilized. The corolla at this stage 

 seems firmly attached to the receptacle, but very 

 soon afterward it falls at the slightest touch, 

 indicating that fertilization has been perfectly 

 accomplished. An examination of the flowers at 

 this stage will also show that the seeds are wholly 

 mature, and we have to conclude from this 

 examination alone that the fertilization was 

 accomplished in the unopened flower. 



i! Nbg tD Studies. 



mical pleasures need not end with the first 



! , and branches furnish an endless 



variation, and arc capable of affording characters 



eliabli and in many cases more 



reliable than, thi ia n I a by leaves, Bi iwei i oi 



fruit. I 01 r 1 1 - . 1 1 ii pb lolo [ii al study, 



a knowledge ol the charactei presented by buds 

 and bl 



A few days ago i came very thrifty 



• i old Along iln- 



