CALOPOGOX pur.riir.r.r.rs. — crass-pixk. 103 



tirely absorbed by the stem that only a small reddish-brown spot 

 is left to show where the leaf mi^ht have been. In the flower, 

 however, the ternary cliaracter is better developed. By the 

 ground-plan given on the plate (Fig. 2), it will be seen that the 

 lowermost division (lowermost, as it appears on our plan), and the 

 two upper ones, standing at obtuse angles with it, form the lower 

 series or verticil, or, as it would be called in other orders, the 

 caly.x. The lower leaf (lower, as before noted), if the three were 

 drawn out on a stem as real, green leaves, would be the upper 

 or third in the cycle, and we see that it has begun to change its 

 form. The next drawing-in of the spiral twist, which has re- 

 sulted in another cycle or verticil of three leaves brought down 

 to one plane, has ended by bringing the upper normal leaf, and 

 the most changeable as we have already seen, just opposite to 

 where the twisting of the lower verticil ended. Now, in other 

 Orchids, such as Blctia TankervillcB, for instance, which the 

 writer has carefully observed, another twist takes place in the 

 ovarium, just as the petals are about to open, and after all the 

 twistins:, so far described, has been done, and the result is that 

 the lip (which in our flower is the uppermost leaf of the second 

 verticil) assumes the position of the lowermost part of the flower. 

 In Calopogoii — and this is the remarkable feature of the geniH 

 — the extra twist has not occurred, and the result of this limited 

 torsion is that the lip forms the upper instead of the lower part 

 of the flower. We have arranged the plan (Fig. 2) expressly to 

 show this interesting result. 



The genus Calopogoii is closely allied to Pogoiiia and to Arc- 

 thusa, and it is a noteworthy fact that our species is generally 

 found growing in the neighborhood of Pogonia ophioglossoidcs. 

 The two are evidently to a great degree companion plants, and 

 it might be profitable to any one interested in evolutionary 

 studies to investigate their ancestry. 



It is almost impossible nowadays to speak of an Orchid with- 

 out touching upon the subject of fertilization, and we cannot 

 refrain from saying a few words in regard to this subject here. 



