ARTIFICIAL POLLINATION OF 



ORCHIDS. 



Fig. 2. I'OLLINIA 

 OF LiCASTE 



Skinneri. 



which, in these plants, presents a strange form. The 

 pollinia and the stigma are always found upon the same 

 column, here as elsewhere, in perfect flowers. In stan- 

 hopea the column is directed downwards, the pollinia 

 have a structure similar to that of lycaste, and the 

 stigma is very straight. , 



Disa grandijlora is 

 another orchid hav- 

 ing a peculiar struc- 

 ture. The column 

 has two viscous discs 

 situated on the side 

 and attached to two 

 long masses of polli- 

 nia, which are plainly separated. 

 The stigma is situated at the base 

 of the column, and appears in the 

 form of a small cushion, a form 

 which is rare. The pollinia being 

 so very large in this flower, it is not 

 necessary that they should adhere 

 entirely to the stigma. 



The catasetums are the most cu- 

 rious orchids. In them the sexes are separated. The 

 male flowers bear two antennas (Fig. 4), which, at the 

 least contact, communicate a vibration to the pollinia ; 

 these are then thrown straight out with considerable 

 force. Therefore it is necessary to direct the instrument 

 used in pollinating straight towards the center of the 

 flower to receive the pollinia. The female flowers of 

 catasetum are so different that they have been consid- 

 ered as distinct species. The female flowers of C. Biiii- 

 gL-rottii, for example, recall, more 

 or less, the flowers of a cypripe- 

 dium. 



The mormodes have no anten- 

 na;, but they also possess the 

 power of throwing out the polli- 

 nia when the pedicel is touched. 

 The latter is found on the ante- 

 rior surface of the column. The 

 flowers of this genus are herma- 

 phroditic. The pollinia of cyc- 

 noches are similar to those of 

 mormodes. The sexes are sepa- 

 rate, as in catasetum. — A. Buyss- 

 eiis, in A\-7'//t- de /' Horliiitltui ii 

 Beige. 



Pollination of the Cypripe- 

 DiuM. — The question of the hy- 



brization of orchids, and particularly that of the cypri- 

 pedium, seems to be the order of the day. Many horti- 

 that they found the stigma on the hip of the flower, culturists and gardeners believe that the artificial cross- 



HE STRUCTURE of the flowers 

 of orchids is so varied that the 

 parts are often hard to recog- 

 nize by one who lias not closely 

 examined them. In most or- 

 chids the stigma has the same 

 ' structure ; it consists of a cav- 

 ity containing a viscid material. 

 But the pollinia, or pollen masses, differ very much. 

 The pollen mass is usually composed of three parts, 

 which can be seen in Fig. i ; p show s the pollen mass 

 itself, ped. its stalk or pedicel, and dv. a viscous 

 disc by means of which the organ sticks to any ob- 

 ject which touches it. 



Oncidium, miltonia, brassia, odontoglossum and tri- 

 chopilia have pollinia of similar structure. In these 

 genera, the sticky disc is turned towards the exterior of 

 the column, and the pollen mass is, therefore, easily re- 

 moved. 



Other orchids have the disk turned towards the inte- 

 rior of the flower (Fig. 2), especially lycaste, zygopeta- 

 lum, scuticaria, vanda, ansellia, anguloa, cymbidium, 

 maxillaria and acineta. Those who work with these 

 flowers should use a hooked instrument, in order to reach 

 the viscous disk more easily. This hook is shown at /, 

 in Fig. 2. The pollen mass is seen at /, and the viscous 

 disc at dv ; si shows the stigma. 



A third series of orchids has pollinia without any vis- 

 cous disk ; the viscid matter, causing the pollinia to be- 

 come attached to the instrument, is then furnished by 

 an organ situated directly below the pollinia and called 

 the rostellum (Fig 3, r). This usually appears in the 

 form of a lip, often split in the middle, as in epidend- 

 rum, and projecting beyond the 

 stigma. In Fig. 3 the pollen mass 

 is shown at/, and the stigma at 

 St. In this class we find the catt- 

 leya, laslia, coelogyne, pleione, 

 masdevallia, epidendrum, calan- 

 the, dendrobium, thunia, phajus, 

 chysis, bletia, cyrtopodium and 

 sobralia. In these flowers the 

 operator must lower the lip of 

 the flower and pass the instru- 

 ment against the column, using 

 sufficient pressure to carry from 

 the rostellum as much of the vis- 

 cid matter as possible. The pol- 

 linia are then easily drawn out. 



The peculiar structure of stanhopea has often puz- 

 zled those who looked for the sexual organs and thought 



6. 



Fig. I. Pollinia 

 OF Orchid. 



Fig. 3. Pollinia of 

 Cattleya. 



