190 Chase Notes on Genera of Paniceae. I. 



Kunth (Paspalum Perrolteti Hook f.) and its close allies have sparingly 

 branched racemes more or less naked at the base forming a panicle not 

 greatly unlike that of Panicum proliferum and yet are true Syntherismas as 

 shown by the spikelets and especially by the cartilaginous-papillose lemma 

 with flat, hyaline margins. Hooker f. (1896 Fl. Br. Ind. 7 : 10) places 

 these and other species of Section Digitaria in Paspalum, saying " As above 

 defined, Paspalum includes the Digitaria section of Panicum, which appears 

 to me to be artificially placed in the latter genus, because of the occasional 

 presence of a very minute scale-like glume at the base of what is the 3rd 

 gl. of Panicum (that opposite the flg.). This minute glume which is present 

 or absent even in the same species, is nerveless and never embraces that 

 above it, as the lowest glume always does* in Panicum proper." The first 

 glume is not only present or absent in the same species in Syntherisma, but 

 sometimes in the same specimens, as in those of P. Perrotteti in the National 

 Herbarium. Nash (Bui. Torr. Bot. Club 25 : 289) while contending that 

 Syntherisma is as worthy of generic rank as are Paspalum, 

 Anthaenantia , Eriochloa, Isachne, Ichnanthus, and TricJio- 

 laena fails to point out why it is so, and adds : " Our own 

 view is that Syntherisma is more nearly related to Paspalum 

 than to Panicum, and if its union with either genus were 

 desirable it would certainly be with the former and not 

 with the latter." If the cartilaginous-papillose lemma with 

 flat hyaline margins be taken for the chief generic char 

 acter, Syntherisma is at once clearly distinguished from 

 both Panicum and Paspalum, with no intermediate species. 

 Description. Spikelets solitary or in 2's or 3's, subsessile 

 or short-pediceled, alternate in 2 rows on one side of a 

 3-angled winged or wingless rachis, the slender racemes 

 usually more or less spreading, usually digitate or in ap 

 proximate fascicles at the summit of the culm, rarely dis 

 tributed along the axis ; spikelets lanceolate or elliptic ; first glume minute 

 or wanting, the second glume equalling the sterile lemma or shorter, fruit 

 lanceolate or elliptic, the flat, hyaline margins white or pale; grain sub- 

 elliptic, in section plano-convex or slightly concavo-convex. 



The affinities of Syntherisma, are with Valola on the one hand and An 

 thaenantia on the other. To the former it is allied through V. Pittieri and 

 the species mentioned above as " Panicum tenerrimum " from Texas. Syn 

 therisma approaches Anthaenantia through Panicum ($ Digitaria) adustum 

 Nees and Anthaenantia Hackeli Arech. allied species, and Panicum badium 

 Scribn. & Merr., which are placed in Syntherisma rather than in Ardhae- 

 nanlia on the following characters : Spikelets in pairs in 2 rows along one 

 side of a triangular rachis ; a minute first glume present (though this has 

 little weight) ; second glume not equalling the sterile lemma (which is 

 empty or contains only a nerveless rudiment of a palea), neither of them 

 broad with deeply folded internerves as in Anthaenantia; lemma not 

 boat-shaped, the hyaline margins broad. In addition to the species con- 



* Hooker was probably not acquainted with the Dichotomous Panicums in which 

 he first glume is often nerveless and seldom embraces the second. 



