BOTANY. 85 



frogs. The colors and spots on the perianth sometimes give the appearance 

 of the skins, of quadrupeds, as the leopard and tiger. These resemblances are 

 often indicated in the generic and specific names. The labellum, in some in- 

 stances, displays peculiar irritability. 



Tribe 1. Cypripediecc. Pollen pulpy granular. Fertile anthers two, Avith 

 a dilated petal-like body (the third stamen) between them. E.xample : Cypri- 

 pedium, or Ladies' slipper, of which various American species exist. 



Tribe 2. Neottiens. Pollen powdery, in numerous minute and angled 

 loosely cohering grains (forming two or four masses). Anther more or less 

 parallel, with the stigma or column erect. This tribe includes the following 

 sub-tribes: Cranichideo', Lister ideoi, Spiranthideoe, PhysuridecB, Diiiridecc, 

 and Tlielyjnitrideoi. Examples : Cranichis, Acroea ; Listera, Neottia ; Sper- 

 anthes ; Goodj^era ; Diuris ; Epiblema. 



Tribe 3. Arethnsfc. Pollen, as in the last. Anther terminal, forming a 

 lid over the stigma. Sepals and petals mostly erect or converging. Sub- 

 tribes : Limnodoridece, AcianthidecB, Caleyidecc^ Pogonidea, Gastrodidece, 

 and Vanillidefe. Examples : Chlorea, Microtis ; Acianthus, Corybas ; 

 Caleya ; Pogonia, Arethusa, Calopogon ; Gastrodia ; Vanilla. The fleshy 

 pods of Vanilla planifolia and V. claviculata furnish the vanilla of the 

 confectioner. 



Tribe 4. Ophrydeie. Pollen cohering in very numerous grains, which are 

 collected on a cobweb-like tissue into tAvo large masses, and affixed to the 

 glands of the stigma. Flower ringent : lips with a spur at the base beneath. 

 Sub-tribes : Serapiadem. Satyriadece, Gymnadenideo', Holothrichidece, 

 DisidecB, Corycidece. Examples : Orchis, Ophrys, Pachitcs, Gymnadenia, 

 Plathanthera, llolothrix ; Disa, Forficaria ; Corycium, Arnottia. 



Tribe 5. Vandece. Pollen cohering in definite (two or four) waxy masses, 

 furnished with an elastic prolongation (caudicle). Sub-tribes : Sarcanthidecc, 

 Cryptochilidea', BrassidecB. ParhyphylUdece, Maxillaridece, CatasetiderB, 

 Notylideoe, lonopsidecE, and Calanthidece. 



Tribe 6. EpidendrecB. Pollen coherent, in definite waxy masses, 

 furnished Avith a caudicle : anther terminal, opercular. Epiphytic or 

 terrestrial plants. Sub-tribes : CcelogynidecB, Isochilidea, Loilindece, and 

 Bletidece. 



Tribe 7. Malaxide<B. Pollen cohering in definite (four) Avaxy masses, 

 without any connecting tissue or caudicle. Sub-tribes : PlearothallidefB, 

 Liparidea. Dendrobidere. and Corallorhizidecc. Examples : Microstylis, 

 Lipai'is, Corallorhiza, Aplectrum. 



Pi 58, 59. ßg-. 8, Vanilla aromatica, or Vanilla. 



Order 35. Hydrocharidace^, the Frog-bit Family. FloAvers spathaceous, 

 unisexual, rarely ^ . Perianth Avith a six-partite limb', the three outer 

 segments herbaceous and equivalent to the calyx, the three inner pctaloid 

 and equivalent to the corolla. Stamens definite or indefinite, epigynous. 

 Ovary adherent, one- or many-celled ; ovules 00, anatropal, frequently 

 attached to parietal placentas ; stigmas three to six. Fruit dry -or 

 succulent, indehiscent, uni- or pluri-locular. Seeds numerous, exalbuminous ; 

 embryo straight, i-adicle remote from the hilum. Floating or aquatic plants, 



85 



