DISTRIBUTION OF SEXES. 



299 



The twelfth group comprises those species which bear pseudo-hermaphrodite 

 female flowers on one plant and pseudo-hermaphrodite male flowers on another. 

 This is observed in species of Buckthorn of the section Curvispina (Rhamnua 

 cathartica, saxatilis, tinctoria), in various Caryophyllacese (e.g. Lychnis diurna 

 and vespertina), in Asparagus (Asparagus officinalis), the Rose-root (Rhodiola 

 rosea), the Mountain Currant (Ribes alpinum), and the Fuller's Thistle (Cirrium). 



Fig. 287. Type ft a dioecious plant: Crack Willow (Saliz fragrtt). 

 i Twig with pistillate catkins. Twig with staminate catkinl. Natural sire. 



The Mountain Cudweed (Gnaphalium dioicwm) and the closely allied species of 

 the same genus, Qnaphalium alpinwn, and carpaticum, al 



thirteenth group contains numerous species all bearing true pistillate 

 flowers on one plant and true staminate flowers on another; they we, 

 dioecious by LinLu, Examples are: Ephedra, Cycads, Juniper, Yew, and Gmkgo 

 (Juniper Js, Taxus, Ginkgo), numerous Sedges (e.g. ^^ 

 VallLria (see fig. 155, vol. i. p. 667), Hemp and Hop V* 

 the Paper Mulberry (Broussonetia papyri/era, see fig. 229, p. 137), Dogs 



