Xysmalobium.'\ lxxxv. ASCLEPiADEiE (brown). 200 



in the bud. Corona-lobes 5, arising from the staminal-column and 

 opposite the anthers, variously shaped, very fleshy, sometimes as thick 

 as broad or laterally compressed, with or without keels or teeth on 

 their inner face, sometimes dorsally flattened, but then comparatively 

 thick and entirely without keels or with only ] rather stout longi- 

 tudinal median keel on their inner face, solid, never cucullate or com- 

 plicate, nor produced into a terminal horn, sometimes with U 

 minute teeth or rudimentary lobes alternating with them at their base. 

 Anthers terminated by a membranous appendage. Pollen masses 

 pendulous, solitary in each anther-cell, attached to the pollen-carriers 

 in pairs by elongated caudicles. Style usually shorter* than the anther- 

 tips, rarely exserted beyond them. Follicles variable in shape, smooth 

 or softly echinate. Seeds crowned with a tuft of hairs. — Perennial 

 herbs with milky juice and tuberous rootstock or roots. Stems 

 erect, rarely diffuse, usually simple and often solitary, but .sometimes 

 much branched at the base. Leaves opposite. Umbels sessile or 

 pedunculate, solitary and terminal, or most of them lateral between the 

 bases of the petioles, and one or two terminal. 

 Species many, extending into South Africa. 



Xysmalobium as liithorto defined is very ambiguous in character, and by the 

 definitions j^iven cannot be distinguished from Asclepiast and Schizoqlossum. 

 Originally it was separated from Asclepias by K. IJrown to include those species 

 which have 5 minute lobules or teeth alternating!: with the 5 coronal -lobes, without 

 giving importance to other characters. K. Urown only refers two species to it, viz., 

 Asclepias undidata, Limi., and A. grandijloray Linn, f., two plants, wliich accord- 

 ing to modern views, cannot well be placed in the same genus. The minnte alter- 

 nating lobules, altliough of specific value, are not of generic importance, since they 

 are present in Xysmalohium clecipiens, N. E. Br., and absent in the closely allied 

 X. Holuhii, Scott-Elliot. In Asclepias also there are some species with, others 

 without them. Bentham & Hooker distinguish Xt/smalobiittn by the following 

 character, "coronal-scales flat, unappendaged," but this character neither applies to 

 all the species of Xysmalohium, nor distinguishes it from Sc/u'zogloisum. This 

 absence of a definite distinguishing character has led to much confusion during 

 recent years; even the same species is referred to another genus by the same or a 

 different author. Vndouhtcdly Xysmalobium, Asclepias, and Sclnzoglossum are but 

 artificial divisions of one natural genus, since they cannot be separated by characters 

 that do not bi*eak down at some point, yet as there are 3 types of coronal structure 

 in the group, it seems iindesiritble to follow Baillon, who in his " H-istoire dcs 

 Plantes," x. 226, unites them, or Schlechter, who in the "Journal of Botany," 1H96, 

 451 (without assigning reasons), unites Xysmalobium with Asclepias. rvtiuns Schizo- 

 glossum and refers some species, which I cannot separate from Xysmalobium, to 

 other genera. Therefore in dealing: with the Tropical African species of this proup 

 I have sorted them as follows : 



All species in which the coronal-lobes arc cucullate or more or less com- 

 plicate or cleft on the inner face, are laterally compressed or at least measure as 

 much from front to back as they do in breadth, with or without a horn or other 

 process in the cavity, and are never dorsally flattened, I refer to Asclepias. 



All species in which the coronal-lobes are dorsally flattened, or if concave 

 or with incurved edges, then always broader than they measure from front to back, 

 usually with 2 slight or wing-like parallel keels and with or without 1 or more hom« 

 or other appendages on the inner face, and are never laterally compressed, cucullate 

 or complicate, or with n single median keel, I refer to ScnizooLOSSi'M. 



