PLANTS OF THE TRES MARIAS ISLANDS. 79 



Collected on Maria Madre Island, May, 1897, by T. S. Maltby (No. 

 105) and E. W. Nelson (No. 4242) ; by J. N. Eose near Colorao, Sinaloa, 

 July, 1897 (No. 1675). 



Wissadula hirsutiflora (Pn-sl) Rose. 



The type of this species came from Acapulco. It is probably com- 

 mon on the west coast, although its distribution and specific limits are 

 not well known. May 3 to 25 (No. 4250). 

 Abutilon reveiitum Watsou. 



This species extends as far north as Arizona. May 3 to 25 (No. 4203). 

 Hibiscus tiliaceus L. 



A common tree in most tropical countries. Maria Magdalen a Island, 

 May 26 to 28 (No. 4328a). 

 Melochia tomentosa L. 



Common throughout tropical America. May 3 to 25 (No. 4205). 

 Guazuma ulmifolia Lam. 



Common throughout tropical America. Maria Magdaleua Island, 

 May 26 to 28 (No. 4325). 



Heteropterys floribunda H. B. K. 



Common in Mexico and Central America. 



Maria Magdalena Island, May 26 to 28 (No. 4323). 

 Guaiacum coulter! ? Gray. 



Seemingly common on the west coast of Mexico. Island specimens do 

 not correspond with the form found on the mainland and may represent 

 an undescribed species. May 3 to 25 (No. 4180). 



Zanthoxyluni insularis Rose, sp. nov. 



Tree 6 to 20 meters high, thornless; leaves oddly pinnate; leaflets 

 6 to 7 pairs, opposite, sessile, obovate to spatulate, obtuse or retuse, 

 2 to 3.5 cm. long, crenate, with large pellucid dots between the teeth 

 and small scattered dots over the surface, glabrous; flowers unknown; 

 fruit small, in a rather compact panicle; pedicels very short; stipe 

 short and thick. 



Collected by E. W. Nelson on Maria Madre Island. May 3 to 25, 1897 

 (No. 4278). 



Zanthoxylum nelsoni Rose, sp. MOV. 



Tree 7.5 to 20 meters high, thornless( t) ; leaves oddly pinnate; leaf- 

 lets about 6 pairs, distant, opposite, shortly petioled, 5 to 11 cm. long, 

 rounded at base, long-acuminate, creuate, glabrous on both sides, 

 thickly set with pellucid dots; inflorescence in small compact panicles; 

 perianth complete; petals 4 (?); fruit large in dense head-like clusters, 

 not stipitate. 



A very peculiar species, unlike any Mexican one known to me. Col- 

 lected by E. W. Nelson on Maria Madre Island. May 3 to 25 ; 1897 

 (No. 4279). 



