SCIENCE-GOSSIP. 



39 



difficulty of eflecting cross-fertilization. The anthers 

 form a cone over the stigma, and the pollen sacs 

 burst almost simultaneously with the unplaiting of 

 the corolla. When the flower is a few hours old 

 the stigma protrudes slightly through the anther- 

 cap, and is visible under a lens through the very 

 small orifice of the corolla-tube. Even admitting 

 that the flower has not fertilized at this early stage, 

 and that the tongue of a butterfly might introduce 

 foreign pollen to it under certain circumstances, it 

 would rarely, in any case, occur. It is well known 

 that all insects soon discover the easiest method of 

 doing their work. In this case there are five open- 

 ings between the tube of the corolla and the bases 

 of the filaments, offering a wholly unobstructed 

 course to the creature's tongue. It would have to 

 use considerable force to insert its tongue under 

 the anthers pressing down on the stigma. It is 

 inconceivable that the flower can receive any aid 

 to cross-fertilization in this way. But we may 

 grant that a cross-fertilization will result in a plant 

 better fitted for the struggle for life than one self- 

 fertilized, and that a small percentage might become 

 cross-fertilized. The question of numbers again 

 forces itself upon us. How many of the seeds of 

 any plant get a chance to develop to a plant again 

 bearing seeds ? How many of the 65,280 seeds of 

 this plant will probably mature — will come to be 

 seed-bearing plants next year ? Only a small per- 

 centage, in any case, ever do. In this case surely 

 very few will, and of these how many would those 

 resulting from a " chance cross" give ? 



Facts of this character are common, but this 

 case presents them in such a remarkable degree as 

 to make it a special one. Heliophytum indicum, 

 a self- fertilizer and wonderfully productive, has 

 maintained a remarkable homogeneity amidst rare 

 variation in the environmental conditions. 



Rhythmic Energy in Plants. 



If we accept the thought frequently thrown out 

 in these contributions, that form results from the 

 various degrees of rhythmic energy in the plant 

 itself, just as it would in the formation of the frost 

 1 'in a v.indow-pane, we can see that environ- 

 ment cannot be regarded as a leading agent, but 

 must take a minor place. 



During the past season I was able to add a new 

 illustration to the list in Pentstemon barbatus. In a 

 large bed with several hundred flower-stems, I 

 collected some twenty erect flowers. In the 

 normal condition th<: three lower segments 

 constitute a lip, and arc so tightly recurved that 

 they press against the tube; the upper > 



ind form an upper lip Hut in the exceptional 



--. noted, thii is all changed. The lobes of 



the corolla arc equal, mewed, and prcned against 



the tube. But the most remarkable change occurs 



lo the 6fth or barren stamen In the 



form this is so differently constructed from the 

 other four that thoughtful observation has to be 

 given before deciding that it is a stamen at all. In 

 these erect, regular flowers there is not the slightest 

 difference between any of the stamens. The fifth 

 is the exact counterpart of the other four. Each 

 one of the five stamens are alternate with the five 

 regular lobes, as they should be in any well- 

 ordered regular flower. Assuredly if a plant 

 always had flowers like these, and only these 

 flowers, it would not be a Pentstemon, but be made 

 to constitute a wholly different genus, if it were 

 not, indeed, referred to another natural order, for a 

 two-lipped and more or less irregular corolla is 

 regarded as a characteristic in Scrophulariacae. 



We may say that nothing but a different degree 

 of growth-energy, accelerating or retarding the 

 spiral development, so that that which should have 

 been left curved was advanced to (or left in) a 

 straight condition, had anything to do with the 

 remarkable change. 



Then we may ask if such remarkably distinct 

 forms can be produced on the same plant and in 

 an exceptional way, what is to prevent the plant 

 from regularly exercising the same force, and thus 

 making the irregular flower the exception ? That 

 this can be done is shown in the case of the upright 

 and nodding lilies already cited, though we have 

 no evidence that a regular and irregular lily ever 

 grew on the same plant as here produced by a 

 Pentstemon. Examples might be found if looked for. 



That these vagaries, once brought into existence, 

 have hereditary powers is too well known to 

 horticulturists to need more than a passing notice. 

 That they are not oftener the parents of a line of 

 new species is probably owing to the fact that of 

 the millions of seeds produced by a single plant, an 

 extremely small percentage ever get the opportunity 

 to grow and again develop to a seed-bearing con- 

 dition. There would be little chance among so 

 many for these exceptional flowers of Pentstemon to 

 perpetuate themselves. 



Though it would seem that in this case environ- 

 ment, as it is generally understood, could have had 

 little to do in developing an irregular to a regular 

 flower, one may plead for life-energy as the chief 

 factor in the production of form and still leav« con- 

 siderable work for environment to do. One cannot 

 well retain as erect a position when holding an 

 umbrella against a driving storm, as if he were 

 simply shading himself on a calm summer day; 

 and there must be some opposing elements or 

 adverse circumstances capable of depressing life- 

 energy as a mechanical force, and with this varia- 

 tion in degree we may reasonably look for a change 

 in form Hut granting all this it must be evident 

 that life-energy, dependent on varying phases of 



nutrition, i-. On- main power In '!■■' Iding form. 



' continued.) 



c 3 



