Rutaceae. 



Leaflets thick coriaceous, opaque, obtuse or rounded, the lateral ones subsessile, 

 truncate at the base, rhomboidal, the lower half much produced, almost auriculate, the 

 rib puberulous or more often glabrate, the median leaflet rarely, articulate; i)anicles simple 

 or compound. 



The writer's number 8071, collected in Mahana Valley, Lanai, is the typical 

 var. y, while number 8217 has the leaves not quite so coriaceous and has densely 

 flowered panicles. 



Var. rigidum Rock var. nov. 

 (Plate 80.) 



A small tree 5 m high, with few very stiff stout branches, leaves three foliolate, on 

 petiole.s of 5 to 6 cm, leaflets ovoid to ovoid-oblong, bluntly acute, truncate at the base, 

 the lateral ones subsessile or on petiolules of 4 mm, the median leaflet on an articulate 

 petiolule of 3 cm, 12 to 15 cm long, 8 to 12 cm wide, (having the largest leaves of any 

 Hawaiian Xanthoxylum) thick coriaceous, opaque, with prominent stramineous midrib 

 and veins; panicles densely flowered, 9 to 12 cm long, on flat, compressed peduncles of 

 3.5 to 4 cm, ultimate pedicels 6 mm, follicle as in the species. 



Collected on the Island of Maui on the northwestern slopes of Haleakala in 



"Waihou gulch, back of Makawao, elevation 3000 feet, March, 1912, in company 



with Pseudomorus Brunoniana and Sideroxylon Ceresolii. Type is number 



10200 in the Herbarium of the College of Hawaii. It is a small tree 15 feet 



high and is peculiar to Mt. Haleakala, where it grows in the drier regions on the 



steep slopes of Waihou gulch. 



From the Kaala Mt., Oahu, Hillebrand describes a variety 8 with 3 to 5-foliolate 



leaves. The writer is not acquainted with this variety. 



Var. anceps Rock. var. nov. 



Leaves trifoliolate on petioles of 8 to 12 cm, pubescent with whitish hair, leaflets lanceo- 

 late to ovate-lanceolate, the lateral ones sessile, almost rhomboidal in outline, very un- 

 «venpided, acuminate at the apex, the terminal leaflet on a petiole of 22 to 30 mm, which 

 is not articulate, 10 to 15 cm long, 3.5 to 9 cm wide pubescent or glabrous above, pubes- 

 cent underneath, especially along the prominent midrib; panicles large 15 to 20 cm, open, 

 many flowered, pubescent throughout, with a common, broad and flat (compressed) 

 peduncle of 6 to 9 cm, ultimate pedicels 5 mm; male flowers: sepals minute dentiform, 

 pubescent, petals cream-colored, 5 mm long ovoid, acute, stamens slightly shorter, anthers 

 orbicular, ovary pronounced, though rudimentary; follicle only 8 mm, minutely pitted. 



A medium-sized tree 20 feet in height, pubescent throughout. It is peculiar 

 to the Island of Hawaii, where it grows near the Volcano of Kilauea at an ele- 

 vation of 4000 feet in the Kipuka Puaulu, which is so rich in species. A number 

 of other species of Xanthoxylum are found in this small area (56 acres), which 

 is surrounded by ancient aa lava flows which are in turn covered by a forest of 

 Acacia Koa. 



Specimens of this variety were collected flowering and fruiting by the writer 

 in July, 1911. The type is number 10201 in the College of Hawaii Herbarium. 

 'The name anceps refers to the broad and compressed peduncle. 



In the same locality another form was collected with 3 to 5 leaflets which are 

 glabrous and coriaceous. In fruit only, the leaves resemble more var. rigidum 

 (no. 10202). 



205 



